This is only a preview of the June 2015 issue of Silicon Chip. You can view 33 of the 96 pages in the full issue, including the advertisments. For full access, purchase the issue for $10.00 or subscribe for access to the latest issues. Articles in this series:
Items relevant to "Bad Vibes Infrasound Snooper":
Items relevant to "Audio Signal Injector & Tracer":
Items relevant to "The Multi-Role Champion Preamplifier":
Articles in this series:
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JUNE 2015
ISSN 1030-2662
06
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Signal
Tracer
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BAD VIBES
siliconchip.com.au
INFRASOUND
SNOOPER
June 2015 1
KIT OF
THE MONTH
“Champion” Stereo/Dual
Channel Preamplifier Kit
NEW
SILICON CHIP JUN ‘15 KC-5531
Use it as a general purpose stereo preamp or as a dual channel preamp. High input
impedance for ceramic phono cartridge or piezoelectric pickup in musical instrument.
Can be configured as single channel with fixed or variable gain, and works with Electret
microphones. Powered from 6-9VDC (eg. 9V battery) or 12-20VDC.
$
Kit supplied with PCB and on-board electronic components for 12-20VDC operation (Electret mic not included,
use AM-4010). For 6-9VDC operation an LP2950-05 5V low dropout regulator is required (use ZV-1645).
• PCB: 57 x 41mm
1695
Available mid-late June 2015
POWER KITS
$
TEST EQUIPMENT KITS
1995
$
Improved Low Voltage Adaptor Kit
2495
Digital Multimeter Kit
SILICON CHIP MAY ’08 KC-5463
KG-9250
Learn everything there is to know about component recognition
and basic electronics with this comprehensive kit. From test
leads to solder, everything you need for the construction of this
meter is included. 9V battery included.
This handy regulator will step down the voltage to run portable
devices. It will supply either 3V, 5V, 6V, 9V, 12V or 15V and deliver up
to 4A at the selected output voltage.
Kit supplied with screen printed PCB and all specified components.
• PCB: 108 x 37mm
Kit includes DMM case, LCD, solder, battery, test leads, PCB,
comprehensive 18 page learning manual and electronic components.
• Meter size: 123 x 67 x 25mm
$
2995
Transistor Tester Kit
ELECTRONICS AUSTRALIA SEP ’83 KA-1119
Have you ever unsoldered a suspect transistor only to find that it
checks OK? Avoid these troubleshooting hassles with this kit - test
drives WITHOUT the need to unsolder them from the circuit!
Kit supplied with a jiffy box, battery and electronic components.
• PCB: 70 x 57mm
$
3395
$
Battery Saver Kit
SILICON CHIP SEP ’13 KC-5523
Ideal for lithium and SLA rechargeable batteries, this smart kit
cuts off the power between the battery and load when the battery
becomes flat to prevent the battery from over-discharging and
becoming damaged. Suitable applications include cordless
power tools, emergency lights, small to medium UPS (up to
approx 300VA) and a wide variety of other devices. Cut-off
voltage adjustable from 5.25 to 25.5V.
Kit supplied with double sided, solder-masked and screen-printed PCB with
SMDs pre-soldered, voltage setting diodes and resistors, and components.
3395
USB Port Voltage Checker Kit
$
5995
SILICON CHIP JUL ‘13 KC-5522
USB Power Monitor Kit
Kit supplied with double sided, solder masked and screen-printed PCB with
connectors for USB 2.0 & USB 3.0.
Kit supplied with PCB with SMD components pre-soldered and LCD screen.
An easy way to test a USB port to see if it is dead, faulty or incorrectly
wired to help prevent damaging a valuable USB device you plan to
connect. Voltage is indicated using three LEDs.
• PCB: 44 x 17mm
KC-5516
Plug this kit inline with a USB device to display the current that is
drawn at any given time. Displays current, voltage or power and will
read as low as a few microamps and up to over an amp.
• PCB: 65 x 36mm
AUTOMOTIVE KITS
• PCB: 34 x 18.5mm
$
55
Soft Start Kit
FOR POWER TOOLS
SILICON CHIP JUL ’12 KC-5511
Stops that dangerous kick-back when you first power
up an electric saw or other mains-powered hand tool to
prevent damage to the job or yourself. Place it in line with
the power tool’s mains power cord and when you squeeze
the power tool’s trigger it will slowly spin up and be at full
power after about a second. 240VAC, 10A max load.
Kit supplied with PCB, silk screened case, 2m power cord and
specified electronic components.
• PCB: 81 x 59mm
$
2295
Courtesy Interior Light Delay Kit
$
3495
Threshold Voltage Switch Kit
SILICON CHIP JUN ‘04 KC-5392
SILICON CHIP JUL ‘14 KC-5528
This kit provides a time delay in your vehicle’s interior light, for you to
buckle up your seat belt and get organised before the light dims and
fades out. It has a ‘soft’ fade-out after a set time has elapsed, and has
universal wiring. 12-24VDC.
A versatile device to switch a relay when its input voltage crosses
a threshold. Use it to prevent a lead-acid battery from being overcharged, or to trigger an extra fuel pump under high boost or anti-lag
waste-gate shutoff.
Kit supplied with PCB and all electronics components.
Kit supplied short-form with double sided, solder-masked and screen-printed
PCB, onboard relay and electronic components.
• PCB: 78 x 46mm
To order phone 1800 022 888 or visit our new website www.jaycar.com.au
• PCB: 107 x 61mm
Catalogue Sale 24 May - 23 June, 2015
Contents
Vol.28, No.6; June 2015
SILICON
CHIP
www.siliconchip.com.au
Features
14 At Last . . . We Drive The Tesla Electric Car
The Tesla is the only all-electric vehicle that really competes with highperformance luxury cars. We had one for a whole day! – by Ross Tester
23 Real “Hands-On”: Owning A Nissan Leaf Electric Car
What’s it like to own an electric car? SILICON CHIP staff member Ross Tester bit
the bullet and bought a Nissan LEAF. Here are his impressions . . .
Bad Vibes Infrasonic
Snooper – Page 36.
25 Tesla’s 7/10kWh Powerwall Battery: A Game Changer?
Dreaming of going off-grid? Tesla’s new 7/10kWh Powerwall lithium-ion back-up
battery is likely to be a game-changer – by Ross Tester
28 The Bionic Eye: Artificial Vision Is Becoming A Reality, Pt.1
New research is leading to promising advances in artificial vision. Pt.1 this
month describes the problems and the challenges – by Dr David Maddison
78 SPIKE: Improved Software For The Signal Hound
Audio Signal
Injector &
Tracer – Page
60.
Enhanced software for the USB-SA44B mini spectrum analyser – by Jim Rowe
Pro jects To Build
36 Bad Vibes Infrasound Snooper
Got a problem with low-frequency vibrations? This Infrasound Snooper
lets you listen directly to low-frequency sounds that would otherwise
be inaudible – by Nicholas Vinen
60 Audio Signal Injector & Tracer
Low-cost unit comprises a 1kHz oscillator & an in-built amplifier so that you can
trace signals through an analog circuit to locate faults – by John Clarke
68 AM RF Demodulator Probe For Signal Tracers
AM RF
Demodulator
Probe For
Signal Tracers
– Page 68.
It uses just a handful of parts and will detect the amplitude-modulated RF
signals that should be present in an AM radio circuit – by John Clarke
74 The Multi-Role Champion Preamplifier
Use it as a general-purpose stereo preamp or as a dual-channel preamp, with a
mic for one channel and guitar or other audio source in the other. It gives good
performance & will work over a wide range of supply voltages – by Leo Simpson
81 WeatherDuino Pro2 Wireless Weather Station, Pt.4
Final article completes the Weather Station by building a handy little Wireless
Display Unit (WDU) – by A. Caneira & Trevor Robinson
Special Columns
53 Serviceman’s Log
Diversifying – it’s not that easy – by Dave Thompson
71 Circuit Notebook
(1) Wireless Door Chime Repeater; (2) High-side Mosfet Switch With
Optocoupler Control; (3) Low Ohms Meter Has LCD
The Multi-Role Champion
Preamplifier – Page 74.
Weather Station
Wireless Display
Unit – Page 81
84 Vintage Radio
The Philips model 198 transistor radio – by Ian Batty
Departments
2 Publisher’s Letter
4 Mailbag
siliconchip.com.au
89 Product Showcase
90 Ask Silicon Chip
95 Market Centre
96 Advertising Index
AJune
pril 2015 1
SILICON
CHIP
www.siliconchip.com.au
Publisher & Editor-in-Chief
Leo Simpson, B.Bus., FAICD
Production Manager
Greg Swain, B.Sc. (Hons.)
Technical Editor
John Clarke, B.E.(Elec.)
Technical Staff
Ross Tester
Jim Rowe, B.A., B.Sc
Nicholas Vinen
Photography
Ross Tester
Reader Services
Ann Morris
Advertising Enquiries
Glyn Smith
Phone (02) 9939 3295
Mobile 0431 792 293
glyn<at>siliconchip.com.au
Regular Contributors
Brendan Akhurst
David Maddison B.App.Sc. (Hons 1),
PhD, Grad.Dip.Entr.Innov.
Kevin Poulter
Dave Thompson
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ISSN 1030-2662
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2 Silicon Chip
Publisher’s Letter
Anti-islanding in grid-tied inverters
is a big drawback
In the past, I have touched on the frustration of homeowners with solar panel installations who have no
electricity during blackouts. They have this wonderful
shiny panel installation which is prevented from generating power during black-outs by the “anti-islanding”
feature of grid-tied inverters! This disadvantage was
greatly magnified for many people in the aftermath of
the severe weather in Sydney at the end of April.
Many thousands of people were without power for more than a week. Just
imagine that: no power at all for a whole week – nothing for light, cooking,
heating, computers, TV and other entertainment or cordless phones – you
could not even charge your mobile phone! And this was in Sydney suburbs,
not somewhere out in the sticks!
No-one was to blame for this situation as the storms downed many thousands
of trees and the electricity linesmen were flat out reconnecting whole districts.
Even as I write, the clean-up of felled trees is still going on and is likely to
continue for another month or so.
Now we all know why this “anti-islanding” feature is incorporated into
grid-tied inverters. It is there to protect linesmen who may be working on the
system when there is a power outage. On the face of it, this is a good idea. But is
it really necessary to also prevent the home-owner from having any electricity
at all when there is a blackout? There are other ways of protecting linesmen.
The most obvious method would be to use the anti-islanding feature of the
inverter to switch a contactor, so that the home-owner’s system was disconnected from the grid but still leave the inverter itself to generate power. Sure,
the home-owner would not get any benefit from feeding power into the grid but
at least he (or she) would still have power while the Sun was shining. While
there would still be no power available at night, most home-owners would
be happy to work around this, knowing that food in their refrigerators was
not going to spoil and many other power-using tasks such as clothes washing
could be done during the day.
No doubt some people would argue that relying on a contactor to isolate the
home-owner’s system could be a recipe for a fatality. But surely a contactor
could be arranged to “fail-safe” so that if it did not work, the system would be
isolated anyway. I am sure that it would possible to arrange for redundancy in
the monitoring and switching to make sure it was always safe and reliable. Of
course, it would be necessary for the grid-tied inverter to still be able to monitor
for the presence of power on the grid, so that the system would automatically
switch back when grid power was restored.
If you concede that this idea has merit, then it is only a small step to allow
solar systems which are grid-connected (no longer “grid-tied”) to have battery
storage so that home-owners can generate their own power during blackouts
at night. The release of the Tesla PowerWall lithium battery system (see article
on page 25 in this issue) makes this a practical scheme.
The solar panels would charge the PowerWall during hours of sunlight and
feed the excess power into the grid. Then if there is blackout, the system automatically isolates itself from the grid and the home-owner can enjoy electricity
as normal. The PowerWall would also have the benefit of smoothing the peaks
in electricity demand from the grid, as it could supply at least some power
after the Sun goes down.
Of course, the Tesla PowerWall might also persuade some electricity customers to disconnect themselves entirely from the grid and thereby avoid paying
daily service charges.
Leo Simpson
siliconchip.com.au
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June 2015 3
MAILBAG
Letters and emails should contain complete name, address and daytime phone number. Letters
to the Editor are submitted on the condition that Silicon Chip Publications Pty Ltd may edit and
has the right to reproduce in electronic form and communicate these letters. This also applies to
submissions to “Ask SILICON CHIP” and “Circuit Notebook”.
Disagreement with topics of
Publisher’s Letters
I would like to again take issue with
your April 2015 editorial (Publisher’s
Letter). As before, I find the subject
covered here has little to do with the
magazine’s content as suggested by the
front page. It is as if the author of this
item is simply using the magazine as a
platform to air his personal opinions.
This seems somewhat inappropriate.
Regarding the subject in the Publisher’s Letter, when I studied technical
subjects at TAFE back in the 1960s we
were often told we could assume the
planet was infinitely large and could
take whatever you threw at it. But
this is wrong. Modern technology has
already used much of the planet’s supply of rare earth metals to a point that
they are now “rare”. Air-conditioning
has not always been beneficial; it was
the source of a new illness, namely,
Legionnaires’ Disease.
I have spent many years working in
technical areas, including broadcasting, and have become very concerned
about the introduction and use of
technologies simply because you can
and not because they fill an existing
need. Mobile phones, for example,
Climate change comments
should not be dismissed
It is with amusement that I again
see the rise of intellectual arrogance
in the Mailbag section (comments
on the climate change debate, page
12, February 2015). To postulate that
only specialists within the field of
physics (or actually any field) can
understand the details of climate
change (or insert relevant topic:
NBN, solar vehicles etc) and come
to a “correct” conclusion is gross
arrogance. I wonder what the other
sciences think of the off-hand dismissal of their expertise and inputs.
If the general readership, which
obviously includes the Doctor,
know what the Gaia hypothesis
4 Silicon Chip
generate their own uses often based
on the expectations of others. I don’t
own one and yet am quite able to survive; why can’t others? In the end the
Earth’s resources are finite and wearing “rose-coloured glasses”, no matter
how strong, will not change that.
Graeme Clinch,
Willoughby, NSW.
Comment: rare earths are still not actually rare. It is true that mining rare
earths may be more expensive in the
future but we are not going to run out.
Legionnaires Disease occurs in poorly
maintained air-conditioning systems
with evaporative cooling towers. It
is not a new illness, created by airconditioning. It is simply yet another
variant of bacterial pneumonia.
Rose-tinted glasses
are ubiquitous
Unusually, I found myself agreeing with the Publisher’s comments
on the maintenance implications of
roof-top solar in the May 2015 issue.
I paused at the statement that DC is
more dangerous than AC, since this
is a contentious issue.
However, it was his advice that solar
advocates remove their rose-tinted
is, then I would say this is a good
place to commence discussion. To
paraphrase, I don’t have to agree
with what you say but I will defend
your right to say it. Discussion is the
first step towards understanding.
As noted in that letter, “real experts
are rarely complacent or absolutely
certain of their conclusions”.
How dare you identify anyone
outside your area of expertise as
not being a so-called “real expert”.
History is littered with examples of
where this constrained thinking has
led to grievous errors in learning
and development, even in physics!
Secondly, if we are to wait for the
statically “absolutely certain answer” we may be too late. The more
glasses that completely bewildered
me. I know of no one who more
proudly wears rose-tinted glasses than
the Publisher. The previous month’s
editorial in the April issue was a classic example. His views on nuclear energy and the benign effects of climate
change are just two examples.
Nothing would suit me better than
the Publisher’s optimistic views of the
future playing out but surely prudence
demands that we all remove our rosetinted glasses and start preparing for a
more renewable future.
Mark Baker,
Perth, WA.
Solar PV installation
experience
The Publisher’s Letter in the May
2015 issue highlighted some issues
which may be of concern for those
who have installed solar photovoltaic
panels on their roof. The accompanying article in the same issue, detailing
the experience of Dr Alan Wilson
(“Home Solar Panel (PV) Electricity
hypotheses that are aired, then the
more informed are the discussions
and the greater will be the know
ledge of what is occurring.
Experts and those with an indepth understanding are required to
balance the arguments and provide
know
ledge and guidance in what
will ultimately be a community/political decision. I n the final analysis,
“the real experts” will only offer their
“opinions” to the decision makers
who, having other goals and agendas
influencing their decisions, will set
our environmental directions.
To stifle discussion is a crime that
future generations will pay for.
Greg Budden,
Woomera, SA.
siliconchip.com.au
Comments about true-RMS voltage measurement
– is it worth it?”) also raised some points which deserve
consideration. Despite these concerns I am of the opinion
that it is still worth doing today but various state governments are hatching plans to create disincentives to limit
the take-up of solar PV installations.
I installed a solar PV off-grid system on my home in May
2009, when such systems were considerably more expensive than they are today. Prior to installing my system, I
ensured that the roof area where it was to be installed was
in prime condition. I have corrugated Colorbond roofing
which had been in place for nearly 20 years but was still
in very good condition. I made sure that all screws were
replaced when fitting the solar panel mounting rails and
that the roofing sheets were not likely to corrode in the
foreseeable future. My home is located about 1.5km from
the Indian Ocean so salt-laden air is not a real issue. However, I can see that those located right on the ocean may
experience corrosion problems in the future.
My household consists of only my wife and myself
(both retired) and we are careful to minimise power usage, although going to the trouble of switching off at the
GPO all devices which run on standby power is going a bit
too far I feel. The house is powered solely by electricity,
augmented by a solar hot water system. The HWS electric
booster is on a timer circuit so that it only comes into
operation during the colder months and only operates for
about three hours during the daytime to moderately heat
the water for showering. Why waste electricity to make
the water really hot when you are going to mix it with
cold water and cool it down again?
My average power consumption prior to installing
my system in 2009 was around 11kWh per day and my
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Thanks for the good article on the Appliance Earth
Leakage Tester in the May 2015 issue but I have just
one comment about “True RMS”. I think you should
point out to the readers that the RMS you referred to in
the article is AC RMS and does not take into account
any DC level that may be present. This is a trap for
the unwary as True RMS readings take into account
any DC level that may be present.
Remember the RMS value is equated to a DC level
that would produce the same heating value in a resistor
(power). So if you have a signal of 100V DC + 20VAC
RMS you actually have 120V RMS!
Most DMMs that I am aware of do not measure this
DC level; not even a good Fluke DMM – which I use.
You have to switch to DC, note that reading, then add
it to the AC RMS reading to obtain the total voltage.
Mike Abrams,
Capalaba, Qld.
Comment: measuring AC voltage when an accompanying DC voltage is present can cause problems for many
multimeters. In those cases, it’s necessary to measure
the AC via a suitably-rated blocking capacitor. Some
older analog multimeters incorporated ranges with a
blocking capacitor and some DMMs have an AC+DC
mode.
June 2015 5
Mailbag: continued
Helping to put you in Control
FRAM Breakout
The KTB-299 is a Ferromagnetic RAM breakout board. FRAM
is a non-volatile memory & it
doesn’t wear out when read or
written to. 64K memory space,
accessible via I²C bus. 3.3 VDC
powered.
SKU: KTB-299
Price: $24.95 ea + GST
2-Button Pendant With ER Stop
Industrial graded, IP66, 2-button control station pendant
comes with ER stop pushbutton. It has contact rating up to
6A <at>250VAC. 4, 6 & 8 button
models, with or without ER stop
button, are also available.
SKU: HNE-1022
Price: $74.95 ea + GST
125mm Siren
IP55 rated, small rugged siren
with 5 selectable sounds. It
comes with a built-in adjustable volume controller from 95
dB to 105 dB. 24 VDC powered.
SKU: QLL-3002
Price: $139.95 + GST
Tri-colour LED Signal Light
One small signal light that can
transmit up to 3 colours: red,
amber and green. High visibility is esured from a distance
by housing the LED in a special
reflector. Selectable steady or
flashing mode. 24 VDC powered.
SKU: QLL-1101
Price:$142.50 +GST
Omega VLF tower
has been demolished
The former Omega VLF Tower
near Woodside, in the Gippsland
region of Victoria was felled on the
22nd April, 2015. The tower and the
Omega Navigation System was the
subject of my SILICON CHIP article
in September 2014 and I mentioned
the proposed demolition in Mailbag
of March 2015 in which I suggested
that concerned readers contact the
relevant minister to oppose it.
This is a sad moment because:
(1) this was the last tower left in the
world that was used for the historically significant Omega Navigation
System and not currently used for
another purpose; (2) it was the tallest structure in the Southern Hemisphere and (3) it was a significant
local tourist attraction and landmark
which was also used for navigation
by commercial fishermen.
Ostensibly, the reason given for
demolishing the tower was that
someone jumped off it, killing themselves. This seems to represent a new
meme in government thinking. Does
that mean that any other structure
that someone illegally climbs and
jumps off will also be destroyed?
The implications of that are quite
striking – no bridge, building or
tower will be safe from the government wrecking ball. Whatever happened to the concept of individual
responsibility?
It’s too bad that no one in government seems to have understood the
significance of the structure; nor
cared. Everyone I know who has an
interest in technology is appalled
at the unnecessary and wanton
destruction of the last tower standing that represented the navigation
system that preceded GPS (former
Station D in La Moure, North Dakota
remains but was re-purposed).
No attempt appears to have been
made to find alternative uses for
the tower nor does it appear that
the opinions of the public were
sought on the matter. A video of this
destruction can be seen at https://
youtu.be/4YhZp4n1xys
I am glad I got to write the SILICON
CHIP article and make a YouTube video (https://youtu.be/S_T7hd0oXUE)
before this vandalism occurred.
Dr David Maddison,
Toorak, Vic.
Servo Trigger
The servo trigger is a small
robotics board that simplifies the control of hobby
RC servo motors. 5 VDC
powered with 3 control settings, configurable input polarity & response
mode.
SKU: SFC-018
Price: $28.97 ea + GST
Switching Power Supply
Universal AC input, powerfactor correcting, single
output enclosed switching
power supply with short circuit, overload and over voltage protection.
320 W, 24 VDC <at>13A output.
SKU: PSM-026
Price: $114 ea + GST
Wind Speed Sensor
The anemometer measures
wind speed between 0.5 to
50 m/s, which is scaled to
a 0 to 5 VDC output. It features reverse polarity and
over voltage protections. 12
to 30 VDC powered.
SKU: FSS-002
Price: $170 ea + GST
For OEM/Wholesale prices
Contact Ocean Controls
Ph: (03) 9782 5882
oceancontrols.com.au
Prices are subjected to change without notice.
6 Silicon Chip
decision to install solar PV was made
in mid 2008 when it was mooted
that electricity costs would rapidly
increase within the next seven years.
In 2008, WA was in election mode
and Mr Barnett was proposing a solar
rebate for exporting surplus electricity
to the grid of around $0.60/kWh if he
was elected. I quickly discarded this
as blatant electioneering and it had no
influence on how I voted. However,
if this rebate did eventuate, it would
have given some recompense against
the high cost of installing a system at
current prices, which in those days
amounted to around $15,700 for a
quality 1kW Sharp/Fronius package.
As it came to pass, Mr Barnett was
duly elected and as I had surmised, he
reneged on the idea of a solar rebate.
The only rebate paid for exported
electricity was to be at the same rate
as customers paid for any electricity
consumed from the grid. The federal
government offered a rebate of $8000
in those days and together with selling
my RECs for around $1000, it ended up
costing me about $6700 out of pocket
to install my system. Today, you can
install a 3kW system for about half
this cost.
As the price of solar PV products was
dropping rapidly, the federal rebate of
$8000 was cut since it was greater than
the cost of purchase and would have
just been a huge gift to home-owners.
I had always considered that a 1kW
system was a too small for my needs
and in February 2010 I purchased the
items necessary to increase my system
to 1.5kW. This would entail extra roof
mounting hardware, three additional
panels and the necessary extension
cables to reach the end of the panel
string. Even though I was able to get
these items at a discounted price from
a wholesaler, it still cost around $2900
all up.
siliconchip.com.au
siliconchip.com.au
June 2015 7
Mailbag: continued
Sprague 500 receiver
used to hunt interference
I was just looking through the
SILICON CHIP website and found the
story on the Sprague 500 receiver in
the September 2005 issue at www.
siliconchip.com.au/Issue/2005/September/The+Sprague+500+multiband+receiver
I used this receiver frequently
from 1967 through 1974 when I was
stationed with AF Security Service
in Berlin, Sinop (Turkey) and Shu
Linkou (Taiwan). At all three places
we had one at our front gate. If an
entering vehicle broke the squelch
they’d be barred from the facility
until they got their ignition system
fixed.
I frequently went off-site to hunt
for RFI. Frankly, the Sprague 500
was a pretty good unit if you knew
Because I performed the installation
myself, I saved on that item but when
all expenses were taken into account,
my 1.5kW system ended up costing me
a staggering $9600. As it eventuated,
the WA government in 2011 decided
to institute a nett feed-in tariff scheme
which would mean existing owners
would receive roughly 47 cents for
each unit of solar electricity pumped
into the grid. Not only this but the fee
would apply for a period of 10 years.
I quickly signed up for this offer.
In 2013, Mr Barnett was starting to
have second thoughts about his generous buyback scheme and sought to
cancel the 10-year contracts and only
how to operate it. We had a vehicle
with an ignition suppression feature
so we could be mobile. I found a lot
of power-line interference, along
with an occasional AM or FM station off frequency. In Taiwan, the
ILS at Taipei airport often radiated
past its limits.
Thanks for the memories.
Mike Dick, SMSgt, USAF, Ret.
Knob Noster, MO.
pay 27 cents for any excess put back
into the grid. This sparked an immediate backlash – not the least of which
came from voters who had helped put
him in power at the last election.
After some discussion and lobbying, Mr Barnett eventually decided
to leave existing 10-year contract
conditions alone for those who had
installed prior to 19 May 2011 and to
effectively reduce the buyback fee to
27 cents per unit for those installing
solar after this date.
Not satisfied that the revised energy buyback fees were sufficient to
reduce the tariff being paid to solar
PV owners, Mr Barnett was proposing
to introduce at the budget this week
a contrived “poles and wires rental
charge”, similar to that proposed in
2013 by the Queensland Competition
Authority where it was suggested that
a fee of $210 per annum would apply
for those who use the public utility
infrastructure to export their electricity back into the grid. I see now that
this idea has proved too difficult to
implement immediately so it has been
put on the back-burner for a while. No
doubt it will come up at some time in
the future.
I find that my 1.5kW system contributes about 50% of my daily requirements year round so that with
the feed-in tariff of 47 cents per kW I
haven’t had to pay for electricity for
the past few years and have actually
ended up with a credit on my account.
As far as my Fronius inverter is concerned, I have found it to be extremely
efficient and reliable – up until about
six months ago, just after the 5-year
warranty period had expired. Since
Fronius were now offering a 10-year
warranty on current products, I imposed upon them to repair my inverter
under warranty and they agreed.
I had done some research and found
that the main board in inverters of the
same vintage as mine were prone to a
flash-over failure after about five years
service, due to dust combined with
atmospheric moisture ingress. It took
about two weeks for a new board to
arrive from Sydney and the serviceman to come around to install it. The
new board was now coated (both
sides) with a semi-flexible epoxy to a
thickness of about 6mm. This measure
was obviously to counter any similar
failure mode.
tel: 08 8240 2244
Standard and modified
diecast aluminium, metal
and plastic enclosures
www.hammondmfg.com
8 Silicon Chip
siliconchip.com.au
During the time it took for the repair
I decided to see what was available on
eBay in the way of a spare inverter to
keep on hand should a similar failure
occur in the future. I was surprised
when I found that a solar company
only a few kilometres away was auctioning unused Fronius inverters of
the same vintage as mine (they had
acquired stock from a company which
had gone into receivership).
I was successful in bidding on a
slightly larger system (IG20) for around
$430. This was about one-third what
my original inverter had cost so I
thought it was a good deal. When it
arrived I removed the main board and
masked off all connectors and components not requiring it, and gave it
several coatings of acrylic conformal
coating. The original IG15 which was
repaired under warranty is now the
spare.
Ross Herbert,
Carine, WA.
Output transformer failures may
be due to paper composition
I have read with much interest the
various comments regarding valve
radio output transformer failures and
I would like to put my view. Like John
Hunter (Mailbag, March, 2015), I questioned Graham Parslow’s reasoning
that excessive anode current was the
usual cause of output transformer failure (Vintage Radio, November, 2014).
Over the years, I have replaced many
open-circuit output transformers. I
usually “patch” a bench-test trans
former and speaker across the output
transformer to assess the overall operating condition of the radio before
proceeding to fit a replacement transformer. In most cases, the resulting
audio has been pretty good. If the
coupling capacitor to the output valve
was leaky enough to cause excessive
anode current, the sound is usually
pretty distorted.
My opinion on the causes of most
failures parallels John’s comments,
with the addition of the following
thought: it is my belief that a significant
problem behind output transformer
failures lies in the chemical composition of the paper used; either between
the layers of turns or between the winding and the paper bobbin. I don’t know
the chemistry behind making paper but
I believe that sulphur is (was?) used.
An extension of this thought is fed by
noting that people can buy “acid free”
paper for archiving important documents. I also can’t help wondering if
the wax might not have been as inert
as the transformer designers believed
it to be.
A further comment: the Rola potted
transformers that John refers to seem
to have been prone to failure too, although maybe not as often as “open”
transformers. I repair and restore valve
radios myself and the Radio Corporation of New Zealand (RCNZ) which
made Columbus and Courtenay (and
other house brand) radios used “Isocore” wax impregnated transformers
in cans. In their later model radios,
Radio (1936) Ltd which made Ultimate (and also other house brands)
used output transformers that were
mounted on fibre washers to insulate
them from the chassis and connected
them to the B+ rail via a 470kΩ resistor.
In both of these brands of radio, I note
that output transformer failure seems
to be about as “bad” as any other set
I work on.
I would also like to comment on IF
transformer and RF coil failure. These
all seem to either go high in resistance
or open-circuit on their primaries, all
having been connected to the B+ rails.
This definitely seems to follow John’s
reasoning on electrolysis but I still
can’t help wondering if the chemical
composition of the paper is still the
primary culprit. Many years ago, I
remember reading that a thought held
by the engineers at the time was this:
it was often women who wound the
transformers and coils and they speculated that maybe their perspiration got
more acidic as they approached “that
time of the month”. There could also
be some credence to their thoughts.
It’s interesting to note that power
transformers don’t suffer from the
same rate of failures as do transformers (or coils) that are connected to a
DC voltage.
Further to John Hunter’s comments
about his belief in fuses. When I repair
or restore a valve radio, I always install
a 250V 1A 32mm long “fast blow” glass
fuse in the Active lead of the power
cord inside the radio. I had the unfortunate experience many years ago when
I had nearly completed an overhaul
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June 2015 9
21173_virtualbench_Ad_57x244.indd 1
3/27/15 9:05 AM
Mailbag: continued
Solar panel roof installations
& nuclear power
In the May 2015 issue, the Publisher’s Letter raised some very
interesting points on the subject
of solar panels. Even though at our
home we have an ideal location
for solar panels, we have resisted
installation on the basis of cost per
10 years. Given that I am now into
my 70s, there is unlikely to be any
financial gain from going into such
arrangement with our service provider. We did the sums and decided
we would be better off to stay out
of it (despite continuing calls from
Mumbai around dinner time).
However, last year we were travelling through France and Italy and we
noted the prevalence of solar panels,
particularly in Italy. With regard to
your comments about roofing, and
we didn’t have that incentive to get
closer to the issue, but a lot of roofs
in Italy are covered in solar panels
and I am trying hard to recall but I
think they were either the actual roof
or very close to the roof so that any
failure of the roof would be obviated.
One area which I noted as being
an obvious location were car parks,
where the shade for the cars was
provided by solar panels – acres of
them. The idea seemed to be to make
carport style parking and use the
solar panels as the shade roof; what
to a set that I had running well in my
workshop as I went in to the house for
my morning coffee. I went back out to
the workshop about half an hour later
to find the radio nearly on fire! The
power transformer was extremely hot.
A subsequent postmortem showed
10 Silicon Chip
a good idea! Unfortunately, most
of this was seen while travelling at
300km/h on their highly effective
rail system. Not only are the Italians
good at opera but now at solar panel
arrangements.
Strangely enough I didn’t see such
in Singapore but the Marina Gardens
have a very high-tech waste disposal
masquerading as garden styling,
another area of “green” technology
that seems to work.
I find the publisher’s support for
nuclear energy refreshing. As I grow
older, I am more and more convinced
that we in Australia should move to
nuclear power. We have the advantage of having much open space in
which nuclear power stations could
be built.
We should also be building solar
power stations like the La Florida
one at Alvarado in Spain. Using
liquefied salt as a medium it produces 432MW. We have the climate
in which we should build several
such plants across the country, thus
providing some flexibility when
cloud happens to reduce output
from one of the plants.
However, I must say that I find an
inconsistency in the publisher’s use
of scientific opinion to show that
nuclear is safe, and rightly so, but yet
he “cherry-picks” the small minority
of climate change opposers. There
will always be legitimate scientists
who challenge the orthodoxy (that is
how science works) but it is undeniably the case that the vast majority of
climate scientists now firmly agree
that climate change is man-made.
We must act now to reduce our
carbon emissions and going nuclear
and building the large solar plants is
the way to achieve that end.
Ken Anderson,
Sale, Vic.
that the phenolic rectifier socket had
shorted (carbonised) across the HT
pins (it would have had close to 750V
across its adjacent pins, being a type
80 rectifier, if my memory is correct).
I can only assume that the socket
had absorbed some moisture hydro-
scopically while the radio was in
disuse and the stress of having about
750V applied was just too much for
the poor socket to handle. I usually
have a 200W lamp connected in series with the AC line to a radio while
they’re soak-testing but I was a bit too
cocky that day and I paid the ultimate
price – $500 to have the transformer
custom rewound!
Peter Walsham,
Pukekohe, New Zealand.
Leo Simpson comments: I worked at
Ducon Condenser Co in the mid-1960s
and it was standard practice on the
production line for polystyrene (Styroseal) capacitors (which had very high
insulation resistance) for women who
were menstruating to be taken off the
winding machines and put on other
duties – otherwise the wound capacitor elements were likely to have a high
rate of rejection.
Airborne radar
story correction
Your very interesting article on
weather radar in the April 2015 issue
refers to a company called ECKO.
However, it should have been EKCO,
as in Eric Kirkham Cole Ltd.
John Leathley,
Perth WA.
Acer netbook
charger problems
Around 2010 I purchased a shiny
new Acer netbook for my wife. It
served her well for around 12 months
but was soon made redundant by an
iPad. The Acer sat in a cupboard for a
little while before being passed on to
my sister who had a need for it.
During this year’s annual visit to my
sister I noticed it seemed to be out of
service again. On enquiry, my sister
talked about her new iPad and fullsized laptop and said she didn’t need
the netbook any longer. I decided to
bring it home at which point she also
explained it no longer worked on the
battery, only the charger.
Once home, there was no real need
for a device with a dead battery and
it didn’t seem worthwhile to purchase
a new battery given all the other new
devices that I’ve acquired since the
departure of the netbook. Back in the
cupboard it went.
One day, when internet searching
siliconchip.com.au
siliconchip.com.au
June 2015 11
Mailbag: continued
Valve servicing
I fix quite a lot of valve-based
equipment. There are the usual dried
up or leaky capacitors, resistors
that have changed value or change
as they warm up, dead valves and
dodgy modifications.
One fault is common to all devices
that mount the valve sockets directly
on a circuit board: one or more joints
will have cracked where the socket
pins meet the board. I am supposing
this is due to differential expansion
and contraction as the socket heats
up and cools down. This is also
probably why point-to-point wired
amplifiers are popular with musicians as they seldom have this fault.
I have devised a fix for the circuit
board problem, which while a bit
labour-intensive, does cure it for
good. After carefully documenting
the existing connections, I remove
the socket and cut a circular hole in
for something else, I came across a
mention in a forum of a firmware
update for battery failures in Acer
netbooks. A quick check on the Acer
website confirmed there was a new
firmware update which was immediately downloaded and installed. After
a reboot or two the system now identified the battery and began charging.
I guess not all fixes are for a physical
failure; it was only the long period of
non use that had allowed the battery
voltage to drop below a threshold the
original firmware could not recharge
the battery from.
Anthony Vine,
Tanilba Bay, NSW.
Potentiometer
testing tip
I’ve been a bit of a train buff since
I was young and the performance of
the train I’m on is of special interest to
me. To find out how fast the train I’m
on is travelling, I usually take note of
the time between the kilometre posts,
although at higher speeds, it is sometimes hard to spot the posts.
People have suggested to me that
perhaps a GPS would do the job but
I’m a bit unsure if it would be reliable
12 Silicon Chip
the PCB, large enough for the valve
socket pins to pass through but small
enough to leave some “meat” around
the hole to allow the socket to mount
via its lugs, spacers, 3mm bolts and
a pair of small holes for the bolts to
pass through.
I then carefully solder the valve
socket pins to the appropriate tracks
on the board, using small pieces
of flexible hookup wire; different
colours help with pin identification
later on. Of course, this is made so
much easier if the PCB is designed
from scratch with the holes and
some nice big square pads at the
edge of the holes.
A PCB offers huge advantages over
point-to-point wiring for the passive
components but falls down for the
power valves in particular. This solution offers the best of both worlds.
Derek Evans,
Daintree, Qld.
on a train. The windscreen in a car is
swept back so a GPS attached to the
windscreen would have good access
to satellites fairly much overhead
but on a train with windows that are
vertical, it would mean that only
satellites closer to the horizon could
be used.
In addition, many train windows are
tinted and I understand that the tinting
on the V’locity trains here in Victoria
and the XPT in New South Wales is a
metallic film-type tinting which may
have an attenuating effect on the signals. So do you think it would work
or would it be a bit unreliable? I suppose I should try to borrow one and
go for a quick train trip and try it out
but I’m not sure that any of my closer
acquaintances have one.
On a different matter, this little tip
may be of use for your readers. I’m one
of those electronics constructors who
use salvaged components wherever
possible. It can be a bit frustrating to
find that a potentiometer which appeared to be OK when checked with
a multimeter turns out to be noisy. So
now before re-using a pot, I always
do this simple test. I connect a bench
DC supply across the outer terminals
(the actual voltage is not particularly
important; 5V or thereabouts is OK)
and connect my oscilloscope between
the wiper and one end.
I then select AC-coupling and a
fairly high sensitivity in the millivolt
region and slowly rotate the shaft.
Any “noisiness” which a multimeter
would miss is very obvious on the
trace. If it is minor, a squirt of contact
cleaner usually fixes it but if there are
noticeable drop-outs then it’s into the
bin for the pot!
Ray Chapman,
Pakenham, Vic.
Comment: we expect that a GPS SatNav could work but it would depend
on reception conditions on the train
and the GPS module’s sensitivity. It
should certainly work on a train with
wooden carriages. The only way to
know is to try it.
Thanks for your tip on testing suspect noisy pots.
Vintage scopes
for a good home
I would like to place the following
note in SILICON CHIP, if possible, as it
just doesn’t sit right with me to have
to throw this old equipment away
without at least offering it to someone.
I have been employed at a powergenerating company since the midseventies. Recently, I stumbled across
these three oscilloscopes that were
once used to service communications
equipment of that era (see photo). I
have not switched them on because
I believe they should be thoroughly
checked first.
These units are now destined for
the scrap-heap so if anyone would
like them for free, they can either pick
them up or be willing to pay the freight
costs and I will send them.
Please contact me at the following
email address: big.penguin<at>bigpond.
com
T. Ives,
SC
Penguin, Tas.
siliconchip.com.au
And we raved about the Nissan LEAF! Now we drive a REAL electric car!
by ROSS TESTER
There are now several electric-only vehicles being sold in Australia
but the only one which is real competition for high-performance
luxury cars is the Tesla. That’s because the Tesla is a luxury, highperformance car in its own right. High-performance, though, is
almost damning it with faint praise!
T
he first thing you notice about driving a Tesla is its
acceleration. It quite literally pushes you back into
the (very comfortable leather!) seat and you think
WOOOOHAAAA!
It’s been compared very favourably with that of a Porsche
or Ferrari but having never quite got to own (or even driven!)
one of those lofty marques I cannot comment.
However, I can say (because Tesla told me!) that over
200m, the new two-motor all-wheel-drive Tesla P85D (not
yet available here) will blow a very much more expensive
Ferrari FF or the popular Porsche Panamera Turbo into
the weeds! (The Ferrari FF starts at about $US300,000;
the Porsche Panamera ranges from about $US78,000 to
>$US200,000).
The P85D will post a 0-160km/h time of just eight seconds and has been clocked at 3.2 seconds for 0-100km/h.
I can, however, comment on the very next thing you
notice: the speedo reading. In the blink of an eye (or two)
you can easily be going FAR above the speed limit. (I was;
fortunately there were no speed radars around . . .).
Top speed of the S85 is a rather impressive 225km/h.
And no, I didn’t try to prove it.
14 Silicon Chip
Incidentally, that model number (70, 85, etc) refers to
battery size - 85 is for the 85kWh model.
It’s a true PEV
Having come from a PEV environment (that’s Plug-In
Electric Vehicle for the great unwashed, as distinct from
PHEV, or Plug-in Hybrid Electric Vehicle. See the following
column “Owning an Electric Car”) I was well-used to the
almost total lack of sound when driving.
OK, there is some road (tyre) noise; at speed there is a
tiny amount of wind noise (more a whisper!) but most of
the time there is no noticeable noise. The Tesla is little different in this regard. The much larger (18-inch or even the
optional 21-inch) tyres are obviously partly responsible for
slightly more road noise but it’s certainly not objectionable.
Where conventionally-powered cars have to go to some
lengths to achieve a relatively noise-free ride, the Tesla
(and we have to say other electrics) do it almost by default.
What sets the Tesla apart from other pure electrics is
the amount of power available and almost contrarily, the
amount of range. (Usually, electric vehicle high power/
performance is at the expense of range. Not so much here).
siliconchip.com.au
Tesla’s new twin-motor
S85D model (available shortly in
Australia), showing the “normal” front
and added rear motors (in red). More importantly,
it shows the battery “pack” – the underfloor area
which houses the 7000 16850 lithium-ion cells wired
in series/parallel to achieve a 400V, 85kWh powerhouse.
The S85 model has a similar configuration but of course
has only the one front-mounted motor. As we found in our
test drives, that still packs an enormous punch!
In the Model S85 we had for (unfortunately an all-toobrief) review, it was VERY obvious that this vehicle was so
far ahead of any other pure electric that there really was no
comparison. Impressive? Not just yes but Hell YES!
Then again, at the price I guess it would have to be. The
basic model sells for more than twice the price of the next
most popular electric vehicle in Australia, the Nissan LEAF.
Yes, we are completely discounting hybrids such as the
Toyota Prius, Holden Volt etc, because these are not electric
vehicles. They are petrol-powered vehicles with limited
battery capability (in the case of the Prius) or with a battery
charged by a petrol motor (in the case of the Volt).
Where are they from?
Tesla vehicles are fully imported from the USA. They’re
built in a plant in Fremont, California, which is a story in
itself.
The Fremont plant was previously used to build GM
and Toyota vehicles in a joint venture called NUMMI.
Covering an area the size of 88 football fields, a section was
purchased by Tesla (reportedly for the proverbial “song”)
after NUMMI ceased production in 2010.
The Tesla plant today bears little resemblance to the
original, with significantly more automation and floors &
walls painted gleaming white to reflect the total build quality demanded by Tesla and its CEO, Elon Musk.
The company
Various news items in 2012 and 2013 had Tesla Motors
in significant financial trouble, with many financial gurus
(and, it must be said, other grinning car manufacturers)
forecasting its imminent demise. Indeed, it was reported at
the time that Elon Musk was on the verge of selling Tesla
Motors to Google (and later confirmed by him).
However, vehicle sales picked up so this sale never
progressed. Tesla kept on producing cars – and reported a
A night-time view of the Tesla S85
controls featuring that magnificent
A4-sized touch screen display.
Virtually every vehicle function can
be controlled from this screen or it
can be used to display the view “out
the back” or as seen here, the GPS
navigation system.
siliconchip.com.au
June 2015 15
Back-seat passenger’s view of the
S85 console. Impressive, isn’t it?
positive cashflow for the first time in the last quarter of 2013.
Tesla’s share price (Nasdaq TSLA), which opened at
$US19.90 in August 2010 was more than ten times this
(~$US226) at the end of April 2015.
In the first quarter of 2015, they delivered more than
10,000 new vehicles but production capacity does not
satisfy demand. The result is that for most models there is
a long “wait list” (in Australia, you are looking at October/
November delivery for vehicles ordered now).
Tesla’s sales model does not include dealers – you buy
direct from Tesla (from their company-owned showrooms).
This has got Tesla into some difficulty in the USA, where
the powerful auto unions have been able to convince
legislators in several states to disallow Tesla’s setting up
showrooms in those states.
The car
You have to say this is one good-looking car. In fact, I
noticed a lot of people admiring it during the day I was
driving it around. The shape and styling has often been
compared to several up-market competitors.
It’s not a small car by any means; at 4976mm long,
1963mm wide and 1435mm high, its not dissimilar to
a large, family sized luxury sedan (think BMW 7-series,
for example). But at 2.1 tonnes, it’s probably about 500kg
heavier than most of its competition – thanks largely to the
700kg, 400V battery pack.
Inside, there’s plenty of room for a family of five (in
very comfortable leather seats, with tons of legroom, even
in the back).
And because there is no pesky transmission tunnel, as
you would find in all front-engine, rear-wheel-drive cars,
the middle back seat is not cramped up.
Luggage space is not skimped on, either, with 894 litres
spread between the boot and bonnet, that’s quite a lot more
16 Silicon Chip
than any car not specifically designed to carry loads (even
then, it beats several mini vans!). Fold the rear seats forward
(and flat) and capacity increases to 1800 litres.
Just in case you missed that “boot and bonnet”, the tiny
engine size means a lot more extra space than you might
expect. And the lack of a bulky petrol tank helps a lot. Both
front and rear luggage areas are fully carpeted.
The instrument “panel”
The first thing you’ll note when you sit in the driver’s seat
is the huge LCD touch screen in the centre of the dash. It’s
hard to explain just how striking – and clear – this screen is!
At 430mm diagonal, (a bit deeper than the size of an A4
sheet of paper) it is mounted vertically into the dash. It
can be set to have two horizontal half-screens or a single
vertical full-screen.
It’s not just an information display – it’s also the mechanism by which the vast majority of vehicle settings, operating information and preferences are displayed and/
or altered.
It’s also the navigation screen – magnificently clear and
detailed (much more than typical vehicle GPS screens)
and it can be made full screen if you wish to either cover a
greater area or obtain even more detail. And it also displays
the images from the rear-facing camera, again, in far more
detail than any vehicle camera we’ve ever seen. Once again,
you can have half screen or full screen.
Entertainment system
We haven’t mentioned the Tesla’s extensive audio/entertainment capabilities – which are superb. You get the
choice of several modes of radio (including internet radio
and a couple I didn’t even recognise!) plus wide-ranging
audio sources – again, either your CDs, DVDs, MP3s, cloudbased storage, internet music sources and much more. The
siliconchip.com.au
Here’s another view, this time 3/4, of the Tesla
Model S showing the beautfully clean lines
and styling, which attracts a LOT of attention!
It’s been compared very favourably with some
much more expensive marques. This could
make the Tesla an attractive target for thieves.
But unless they have the unique key, good luck
with that! Even then, with Tesla’s smartphone
app, you can see where your Tesla is at any
time to within just a couple of metres. The car
features an incredible amount of electronics
and “creature comforts”.
premium audio system is reported to have been developed
“from the ground up” by Tesla but other reports suggest
Alpine might figure in their somewhere.
“Starting” the Tesla
As you approach the Tesla (assuming, of course, that you
have the key) the main thing you notice is that the previously flush door handles move out, ready to open the doors.
There is nothing, as such, to “start”. Entering the car and
sitting in the driver’s seat lets the system know you are
ready to “rock and roll”. Just about everything is automatic.
Placing your foot on the brake and moving the “gearstick”
(which is merely a stalk on the right-hand side of the steering column) to F or R sets the car ready to drive. Take your
foot off the brake and it will gently start rolling – as long as
you have previously set it to “creep”. A word of warning:
don’t plant your foot on the accelerator or you’ll probably
leave your breakfast back where you started!
Incidentally, proving that software developers have a
sense of humour, Tesla engineers have labelled the twoposition acceleration mode settings “sport” and “insane”!
“Starting” also initiates all the other processes that go
on in the car. If you’ve entered a personal profile, it adjusts
everything (seat position, air con, driving preferences, etc)
to that. If not, the previously used setup is resumed.
Now you can also set up profiles, navigation and so on for
this trip. Obviously, this should be done while stationary,
- setting up while mobile is definitely not recommended.
Most setup is done on that beautiful, big touch screen right
in the middle of the dashboard. Even “stuff” that has external controls is mostly accessible via that screen as well.
Exiting the car
This takes a little bit of getting used to, because you don’t
turn a key off or even push a button – there is nothing to
shut down. The car simply “goes to sleep” when you put
it in “P” (for Park), lock the door and walk away.
It’s a bit disconcerting to look in through the window
and find the dashboard still activated, the touch screen still
displaying pictures or vehicle data . . . and so on.
But walk away from the car (obviously taking the “key”
with you) and very quickly it all shuts down by itself.
The motor
In the S70 and S85, a single 310kW, 600Nm three-phase
AC induction motor drives a single speed 9.73:1 gearbox
which drives the rear wheels. The gearbox only has forward
and reverse (and neutral/park) options selected by a stalk
on the right-side of the steering column.
The motor occupies quite a bit less space than an internal
combustion engine – sure, there are ancillaries such as the
AC inverter, air conditioning unit and so on but the result
is the “engine bay” is rather roomy, so much so that it is
given over to luggage space.
The S85D model, when available here, will have two
electric motors (totalling 515kW and 931Nm) and drive
all four wheels.
The battery pack
It may surprise you to find that the lithium ion battery
pack consists of many thousands of small cells – in fact,
“18650”-sized 3.7V cells (or 18mm diameter x 65mm long,
the same as found in many small rechargeable consumer
products, toys, etc) are connected in series/parallel to
achieve a high capacity (85kWh), high voltage (400V)
battery.
This is housed under the floor of the vehicle and is in fact
a stressed member of the chassis, helping provide rigidity
to the rear of the car. This also brings the centre of gravity
to the lowest point possible, considerably helping with the
car’s roadholding.
Tesla’s batteries, supplied by Panasonic from Japan, have
an energy density of 121Wh/kg, which are the most energydense packs in the industry. Compare this to the Nissan
LEAF’s energy density of 79Wh/kg and its not hard to see
why the Tesla range is so significantly higher.
Where are the Australian government electric vehicle incentives?
In most countries overseas, governments encourage electric car purchase through attractive (sometimes VERY attractive) incentives.
These range from discounts or rebates of taxes, “green” incentives, use of transit or special lanes, reserved parking (often with free
charging facilities) and so on. For example, the US federal government offers a $7500 federal tax credit for personal PEV purchasers.
And some states top that up with another rebate ($2500 in California, for example).
The UK has several incentives, ranging from a £5000 government grant, to no road tax, showroom tax or luxury vehicle tax and even
an exemption from London’s congestion charge. For companies, they offer a 100% first-year write-down allowance.
Here in Australia, there is little government incentive to buy an electric car. The government’s luxury car tax is less for a fuel-efficient
vehicle (woopie doo – that applies to all fuel-efficient vehicles), while in the ACT electric vehicles attract no stamp duty.
But that’s about it. In NSW, the incentives and/or reductions amount to a very round number.
siliconchip.com.au
June 2015 17
Here are two views of the Tesla most owners will never see: at left, looking inside the “engine bay” showing just how
little room the engine actually takes. The rest are things like air conditioners, gearboxes, and so on. When completed, the
whole of the additional space is given over to luggage space. The view at right is from the other side of the engine, over the
battery compartment, from what would be cabin space.
As mentioned earlier, there is a choice of 70kWh or
85kWh batteries. Until recently, Tesla offered a cheaper
60kWh battery pack. While slightly smaller than the current model’s packs, this 360V, 459kg battery gives a good
idea of the way so many cells are packed into the space.
In the 360V battery, 69 steel-cased cells are wired in
parallel to form a “brick”; 99 bricks are connected in series
to form “sheets” and 11 sheets form the whole battery pack
– a total of 6831 cells. The battery is liquid-cooled and cell
temperatures are constantly monitored by internal sensors.
Lithium ion cells cannot be charged when they’re below
0°C, so if the temperature approaches zero the cells are
heated at the same time as they are being charged. At the
opposite end of the temperature scale, above a set threshold, cold air from the vehicle’s air conditioner is directed
through the pack to allow charging in very hot climates.
Because lithium ion cells contain neither heavy metals
nor toxic materials, at the end of their life the battery packs
could theoretically be disposed of in landfill. However,
The rear-view camera vision
quality is superb – as good
as any we’ve seen. Here the
screen is shared with GPS
navigation – either can be
made full screen.
18 Silicon Chip
Just a tiny part of the Tesla’s
comprehensive entertainment
system – all touch-controlled,
of course. It remembers your
favourites so you don’t have
to go hunting for them.
Tesla goes one better: it has a recycling program which
reuses or recycles over 60% of the battery already and aims
to increase that to 90% in the future.
New battery “gigafactory”
Tesla is currently building a $5 billion dollar battery
research and lithium-ion manufacturing facility on a 980
acre site outside Reno, Nevada. This alone is worth a story
(and many have been written!) about the way Elon Musk
and his team managed to build this mega-factory with $1.4
billion in tax breaks, free land and other incentives from
the state of Nevada.
Looking to the future, the company has options on another 9000 adjacent acres, which includes 7000 acres for
a 140MW wind-farm.
It will be a net-zero-energy factory, powered by renewable
energy – solar, wind and even geothermal.
Production will be ramped up from 2017, with 50GWh
in annual production by 2020.
It’s telling me that I have
311km of range left in the
battery – but you wouldn’t
discharge to flat in order
to give your battery the
maximum lifespan.
Just about everything can be
controlled from the touch
screen, even such niceties as
mirror tilt (in reverse) and
mirror fold (when you stop
and get out of the vehicle).
siliconchip.com.au
Inside Tesla’s manufacturing facility at Fremont, Cal, USA.
The plant, now gleaming white inside, once manufactured
GM and Toyota vehicles . . . and went broke! Tesla was
reported to have bought the plant for next to nothing!
Here’s Tesla’s huge new $5 billion battery production
and research centre now under construction near Reno,
Nevada, USA. The whole of the roof will be clad in solar
panels and the building energy self-sufficient.
Strangely enough, some reports suggest that Panasonic
will still make the li-ion cells in this factory. But according
to other reports in recent months, Tesla will also be manufacturing a range of large home and industrial batteries to
either store solar power generated during the day or even
store low-cost off-peak power for use during much more
expensive peak times. (See the report “Tesla’s PowerWall”
later in this issue.)
It remains to be seen how successful this side of the
enterprise will be – but if Elon Musk has anything to do
with it . . .
Sydney or Sydney/Brisbane.
Tesla currently has Superchargers at its St Leonards
showroom and also at the Star City casino (both in Sydney).
We understand that Superchargers at the Tesla showroom
in Chadstone (Melbourne) are imminent, if not already
available. Tesla has recently announced a Supercharger
for Goulburn, to add reassurance to the Sydney/Canberra
journey.
Tesla vehicles may also be recharged (albeit usually at
a slower charge rate) at the many public charging stations
now emerging around major cities. There are currently more
than 200 public and private charging stations in Australia.
A 230VAC single phase EVSE (Electric Vehicle Supply
Equipment) “smart cable” is also included in the price of
a Tesla – this must of course be installed in the owner’s
premises at their cost.
In December 2014, Tesla (USA) announced that they
were embarking on a battery pack swap program with
invited Tesla owners. While still a pilot program (and not
available in Australia) Tesla is confident that if and when
implemented, the battery pack could be swapped for a
Charging, range anxiety etc
With a quoted range of up to 500km per charge, most
Tesla owners don’t suffer anything like the “range anxiety” owners of other electric cars experience. This can
only improve in the future, with Tesla Australia planning
to locate their “Supercharger” charging stations at suitable
distances along the routes between eastern capitals – from
Sydney to Melbourne by the end of 2015 and Sydney to
Brisbane by the end of 2016.
The Supercharger provides up to 135kW, giving 85kWh
models almost 300km range in about 30 minutes. So basically it’s stop for a coffee, stretch your legs and charge the
Tesla at the same time.
500km is more than enough range to travel, for example,
from Sydney or Melbourne to the snowfields (where the car
could be charged from ordinary power). It would also allow
a single (or at worst two) stop trip between Melbourne/
When the right side
of the speedo shows
green, the Tesla is
putting power back
into the battery (via
regenerative braking).
Above this is an
orange zone, showing
the power (in kW)
being used at the
time. The left side is a
conventional speedo;
a digital equivalent is
displayed in the centre.
siliconchip.com.au
Is lithium-ion still the way to go?
Tesla is putting an enormous amount of faith in the lithium-ion
rechargeable battery it currently uses to power its vehicles.
But many critics are already saying that just as lead-acid batteries have had their day, the lithium-ion cell is also on the way
out, promoting instead the aluminium-air batteries currently being
developed by several organisations around the world.
An aluminium-air battery generates electricity from the chemical
reaction of oxygen (from the air) and aluminium, using water as
an electrolyte. Their theoretical capacity is some 40 times greater
than a similar-sized lithium-ion cell.
Until now, however, this approach has been stymied by the
reaction consuming the aluminium anode, which must be physically replaced rather than recharged.
Last January, Japanese company Fuji Pigment announced that
it had managed to suppress corrosion and reaction by-products,
creating an aluminium-air battery that can be recharged by simply
adding water.
Ahh, isn’t that the holy grail: when “fill er up” means grabbing
the garden hose?
June 2015 19
Luggage space can only be described as cavernous – and
there’s up to 1800l with the rear seats folded forward.
fully charged pack in less than one minute (less time that
it takes to fill a fuel tank!) and would indeed cost less than
a tank full of fuel.
This program is being evaluated to test technology and
assess demand – ie, whether they are prepared to pay a
small amount for a lightning-fast “charge” by swapping
batteries, or would they prefer to fast charge at one or more
“Supercharger” rechargers, at a rate of 640km range per hour
of charge (or a full battery in less than an hour).
The third option, obviously, is to charge at home or at
a standard rate charger. The advantage of the latter is that
many of these are free to use!
While on the subject of range, Tesla assured me that the
range displayed on the dashboard has proved to be extremely
accurate, much more than that of (ahem!) the Nissan LEAF.
Whether this is true or not is open to conjecture because any
number of on-line forums state the opposite – they claim
the “300 mile” range quoted by Tesla is much more likely
to be in the low 200s, and sometimes worse.
Once again, it all depends on the way you drive, the
temperature outside the car, the terrain, the state of charge
(and the state of battery) . . . all those things which affect
all other electric cars.
Cost to charge
How much does it cost to charge a Tesla – and therefore,
how much does it cost to run?
That is a rather difficult question to answer because there
are so many variables – the amount of charge left in the battery, for example, the cost of the mains power being used
and even your electricity usage (high power users usually
pay a premium).
We’ve already mentioned that Tesla’s SuperChargers,
many street-side and carpark chargers don’t actually charge
you for power, so if you can use one of those at least most
of the time you’re streets ahead! Note, though, that many
do have a cost – but they’re not charging sheep stations (no
pun intended).
If you have to pay for power (eg at home), we’ve been
assured that EVSE equipment can legally be connected to
“off peak” circuits. In most capitals this costs less than 10c
per kilowatt-hour. Or, if you have a smart meter, charging
during the lowest rate period (usually 10pm-7am) will also
20 Silicon Chip
Almost hidden in the front bumper is the Tesla’s forwardfacing radar unit which is part of the anti-collision system.
Get too close to the vehicle in front and the Tesla will slow
you down, or even bring you to a complete stop if necessary.
get you similar rates.
So if, for example, you’re charging at the rate of 10A
(2.3kW) it’s going to cost you about 20c/hour to charge. If
your (pay-for) charging station can deliver the (often very!)
much higher charge rates the Tesla can handle, multiply up!
For example, when I returned the review Tesla it was
plugged into the St Leonards Supercharger and displayed
a peak charging current of some 400A (92kW!) for half an
hour or so, dropping quickly as the battery charged. At offpeak rates a full charge might cost a few dollars. Remember,
though, that gives up to another 500km range.
Battery safety
Overseas (notably the US), there have been a few highlypublicised Tesla fires. However, given the number of Teslas
now on the road, that number is very small – and analysis by
Tesla and accident investigation authorities has not shown
any cause for major concern. In fact, one report said that if
it was anything but a Tesla, the outcome for the occupants
would arguably have been much worse.
When a petrol-powered vehicle has a serious accident,
there can be a lot of fuel released and it can (and often does)
catch fire, sometimes explosively.
A battery vehicle involved in a serious accident is much
less likely to suffer in this way because so much attention
The gear selector is actually a stalk on the right side of the
steering column. That took a bit of getting used to – every
time I went to turn left I put it into neutral . . .
siliconchip.com.au
The green and blue beams in front of the car come from
the on-board radar systems, while the yellow shading
shows how the Tesla senses vehicles all around through its
camera systems. The company has already demonstrated
experimental autonomous (so-called “driverless”) cars
using this and even more advanced technology.
Yes, it was a demostration for the media but last year Elon
Musk showed how quickly a Tesla could have its batteries
changed – in fact, two Teslas had batteries swapped in
the time it took to fill an equivalent petrol vehicle with
fuel. Tesla are working on a pilot program to see if battery
swapping would be popular enough to be viable.
has been paid to shielding the battery pack against external damage, through the use of protective enclosures and
jacketed cables. Even access to the high-voltage components
requires special tools.
In the event of significant impact or rollover (including
air bag deployment), the high-voltage supply is automatically disconnected inside the pack. Universal (international)
marking codes are used to enable first responders to disconnect power safely.
Two others at the sides look for the white lane markers –
they’re the ones which warn you if you’re drifting – while
another, forward facing, is for anti-collision avoidance in
conjunction with a bumper fitted radar. It first warns you,
then takes action, if you are too close to the car ahead at the
speed you are doing (it will even bring the car to a complete
stop if necessary). The thresholds are all settable.
One query I had was if any of the cameras recorded, a
la a “dash cam”. Unfortunately, the answer is no, although
I wouldn’t imagine it could be that hard to implement at
factory level. Still, amongst all the incredible technology
already in the Tesla, it’s a small quibble.
Built-in safety
Tesla sports an independent 5-star safety rating, not just in
all their models but in every subcategory (the highest score
ever recorded). There are so many safety features inbuilt
(or available as options) that it is difficult to list them all.
But one which caused us some brief angst, believe it or
not, was the car’s out-of-lane warning – only because we
didn’t know what the vibration was all about (it’s almost
like a really bad tyre balance problem)! Tesla told us that
was a particularly common “complaint” amongst new Tesla
owners, like “what’s wrong with my car!!!”. They’re happy
to say “nothing” but then it becomes a diplomatic problem
to suggest “it’s your driving!”.
There are four cameras built into the Tesla, one, rearfacing, is for the brilliantly clear rear-view video screen.
Where’s my car?
When I first saw the LEAF, Nissan told me it had an
inbuilt 3G phone system which called the company every
night with operational data. I asked if this could be used
to interrogate the car to check its location (eg, if it’s stolen).
Nissan told me that Australian privacy laws meant this
could not be done (they’d tried, very hard).
Obviously Tesla had no such problem. They too have
a built-in 3G data system but theirs can also tell you (eg,
via a smartphone app) exactly where the car is. Tesla’s
service manager showed me where the five cars on hand
were – within a couple of metres (including the one I was
standing alongside).
So if (somehow!!) your Tesla is stolen or hijacked, you can
see exactly where it is. It’s the same technology that allows
Tesla to wirelessly update the software and firmware which
runs the car, or allows the owner to wirelessly set charging
parameters, climate control and so on.
Autopilot
The “charging port” is located just in front of the left rear
tailight assembly. Quite extensive charging information is
displayed on both the dashboard and LCD screen.
siliconchip.com.au
Reports recently have suggested Tesla is well on the way
to producing a driverless car. This could be a natural spinoff from the Tesla’s “Autopilot” option, where the vehicle
automatically follows the road, steering around curves
and varying its speed to match traffic flow. It also allows
automatic lane changing – tap the indicator and the Tesla
changes lanes when it is safe to do so!
It will also notify you when it finds a parking spot – then
automatically parks in it, controlling steering, acceleration
and braking to back smoothly in.
June 2015 21
TESLA MODEL S – SPECIFICATIONS
Body
Length:
Wheelbase:
Width:
Track Front:
Clearance:
Head room:
Leg room:
Turning circle:
Curb weight :
Drive
Battery:
Motor:
Drive inverter:
Charging
Inside each Tesla showroom you’ll find their “Design
Studio” which lets you choose colours and trims, wheel
types and so on. The car will be made to your specifications
in America and delivered to Australia.
Another nicety: sync your calendar/diary to the car (via
your smartphone) and it will check current traffic conditions to make sure you leave in enough time to make your
appointment. Before that, though, it turns on the climate
control to your chosen (preset) levels. It can even automatically open the garage door and pull out of the garage by
itself, to meet you at the curb!
Yes, many of these things are options but they do give
some indication of the sophistication (for want of a better
word) built in to this remarkable machine.
Machine? I reckon it’s almost human!
4980mm
2960mm
2190mm (With mirrors folded 196mm)
1660mm, Rear 1700mm
140mm (With air suspension 120 - 160mm)
Front 990mm, Rear 900mm
Front 1080mm, Rear 900mm
11.3m
2112kg
70kWh or 85kWh, lithium-ion battery,
microprocessor controlled
Three phase, four pole AC induction motor
with copper rotor
Variable frequency drive and
regenerative braking system
10kW-capable on-board charger with the following
input compatibility: 85-265V, 45-65Hz, 1-40A
(optional 20kW-capable dual chargers increases input
compatibility to 80A)
Peak charger efficiency: 92%
10kW capable Universal Mobile Connector with
120V, 240V and J1772 adapters
3 seconds.
And then there’s the all-wheel-drive two-motor S70D
announced only a few days ago (it’s not yet available in the
states so will be some time coming to Australia).
Musk has stated that he aims to have a “Tesla for the
masses” before too long. With a cheaper battery (which is
not too far away) he aims to have a $US35,000 Tesla available by about 2017.
And we’ve already mentioned Tesla’s incursion into
Where to from here?
other battery applications – and their continual research
We’ve only been able to cover some of the rather amazing into extracting every last milliamp from the cells. They’re
inclusions in the Tesla S85. There’s plenty more informa- reported to be well advanced in nano technology, increastion on Tesla’s website(s) and numerous third party forums ing the internal surface area of cells – and therefore making
and websites if you wish to know more. But if you are at them perform even better.
all interested in having your own Tesla, we suggest getting
Elon Musk stated that the new Reno facility, which will
onto their Australian website and organising a test drive. cost about $5,000,000,000 (yes, B for Billion!), should be
You won’t be disappointed!
online and producing batteries by the end of 2016.
We’ve already mentioned
He’s also said he wants
the all-wheel-drive, twin mothat plant to be able to make
How much, where from?
tor S85D model already rehalf a million battery packs
The Tesla S85 that we had for review sells for $AU129,000 each year – and that’s equal
leased in the USA and not too
far off here (but join the queue on the road.
to the whole world’s current
The new S85D will, when available sell for $169,000 on the road. production!
if you want one!). From the
There is a slightly lower cost S70 available which also lacks
outside, apart from a couple of
Impossible? Maybe . . . but
badges it’s the same as the S85 some of the “niceties” (but is an outstanding vehicle nevertheless) “Do the Impossible” is one of
SC
model . . . until you “lift the and it sells for $99,000 on the road. An S70D (all wheel drive, two Tesla’s slogans.
lid”. Its performance, subject motors) has also recently been announced in the USA.
You can’t walk in, pay your money and drive out with a Tesla.
of numerous tests overseas,
is simply outstanding. Add- There’s quite a waiting list (several months), to some degree Our thanks to Heath Walker and
ing the second motor sacri- caused by the inability of Tesla USA to meet international demand. Huw Williams of Tesla Australia
To get on the waiting list, (or even to organise your own test for their assistance in making
fices a bit of range (<10%) for
greater speed and even more drive) you need to get in touch with Tesla Motors Australia, 10 the S-85 available for review.
neck-snapping acceleration, Herbert Street, St Leonards NSW 2065. Tel (02) 8424 9500, website Photo credits: Tesla, Kevin
with 0-100km/h in just over www.teslamotors.com/en_AU
Poulter and Ross Tester
22 Silicon Chip
siliconchip.com.au
Real “Hands On”: Owning an Electric Car
R
range. The official figures are
eaders may recall that we
just a tad optimistic!
have previously reviewed
Nissan claim “up to 170km
two 100% electric cars:
range” on a full charge. There
the Mitsubishi iMiEV (February
are the usual disclaimers about
2011), followed by the Nissan LEAF
how and where you drive,
(August 2012).
temperature, etc – just as you
We also tried to get hold of
might expect in a petrol or
a Holden Volt when they were
diesel-powered car.
released but are still waiting (two
There’s even a cute “range
years later) for the General’s PR
gauge” on the dashboard which
people to get back to us!
tells you how much battery
It’s probably just as well that we
charge (in kilometres) that
didn’t get to review the Volt because
you have left (sort of like a fuel
unlike the iMiEV and the LEAF, it’s
gauge in reverse).
not a true electric car – yes, it runs
Have a look at some of the
off batteries but has a small petrol
online forums and you’ll find
motor to charge those batteries. “Hah hah hah. . . you’ll need a l-o-n-g extension lead!”
Therefore, it requires fuel, not too dissimilar to other “hybrid” some pretty disrespectful names for this. Some of the more genteel
electrics such as the Prius, some models of BMW, Lexus and refer to it as a “guessometer”. Good name, that!
As my commute to work is <10km, 95% of the time range doesn’t
Toyota Camry (among others).
We were particularly impressed by the LEAF. I recall saying matter to me but the very best I’ve been able to achieve on a 100%
charge, even when my range shows 160-170km – driving very
that if I had a spare fifty grand, I’d buy one. I didn’t – so I didn’t!
Circumstances change, not the least being a $12,000 price drop conservatively, in “ECO” mode, air-con off, etc etc – is about 135km.
Steep and/or long hills knock the range around dramatically – and
so last June (and prompted by a failing 16-year-old SUV) I bit the
if you know the northern beaches of Sydney, you’ll know that it is
bullet . . . and bought a LEAF.
I did this with my eyes wide open – I’d read everything I could ALL hills. I live not far above sea level – to get anywhere means
find and knew that it was strictly a commuter car with limited an uphill to start off with. Heading north-west from my place is a
range. My partner has a Hyundai ix35 – if we wanted to go away long (7.5km) uphill, ranging from moderate to quite steep. That
any distance we would take that. So yes, you pretty-much need 7.5km costs me up to 40km range on the guessometer!
Sure, you get some back with downhill regeneration – but I
to be a two-car family OR be prepared to drive your LEAF to the
would be extremely surprised to find anyone in Sydney who gets
airport and (if you need one) hire a car at your destination.
But there were a few things I was to discover about the LEAF anything like 170km range on a charge. And remember, you have
to be able to charge at the opposite end to come home again. So
only after regularly driving one for nine months or so.
First of all, I have to say that I am very, very happy with the LEAF. unless you’re staying long enough (overnight?) AND can plug in
It’s by far the smoothest car I have ever owned (or until the Tesla to charge, the distance you can travel away is effectively halved!
As an example, in February and March I made a few trips from
test review even driven) and it is by far the quietest.
I’m also extremely happy with its performance. Normally, I’m a Narrabeen to Umina, a distance of 85km. That trip encounters
pretty sedate driver but if I really want to get away first at the lights, some not inconsiderable hills (both directions start with a long
I can virtually always do so – even against some “performance” uphill) and I must admit to some range anxiety.
With a 100% charge to start, I had between 15 and 25km range
cars. The LEAF has incredible down-low torque and acceleration.
left – and that’s limiting my speed to 100km/h on the M1 motorway.
I’m also rather happy with my “fuel” consumption.
Normally, I limit the charge (automatically) to 80% of capacity, as I had previously noted the battery drain difference between 100km/h
suggested by Nissan to maximise battery life, and require a charge and 110km/h (a lot more than 10%!) so was not willing to risk it.
There’s an on-dash active range map which suggests I could
(usually) only about twice a week. While the supplied “charger” is
fitted with a 15A mains plug (and therefore requires a 15A dedi- reach Newcastle on one charge. Oh yeah? I’d like to see that!
Lastly, I’m often asked about battery longevity – that is, how
cated outlet) I’ve measured the charge at 9.75A (<at>230VAC), with
no real difference between a full battery or a half-charged battery. long the on-board 360V Li-ion battery will last before it must be
My first electricity bill with the LEAF was almost exactly $100 replaced. Nissan guarantee 80% capacity after 10 years and some
more per quarter than the corresponding quarter the year before. reports I’ve seen suggest they expect 15 years+.
The problem is, of course, that we’re only a third of the way
When petrol was between $1.00 and $1.30 per litre last year, I
would have put $100 in every 2-3 weeks! So it’s not too much through that 15 years (since introduction), so no-one really knows.
of a stretch to say that my “fuel” bill has dropped by ~75%! Of But apart from a few horror stories (manufacturing faults?), battery
course, petrol prices dropped significantly in late 2014/early 2015 longevity is largely proving to be at least as good as projected.
All of this, though, makes Tesla CEO Elon Musk’s latest statebut as I write this, they’re creeping back up again. . . I’m laughing!
ments about long life (>15 years) and long range batteries (300
But what about the negatives?
and even 500+ miles) sound rather exciting, especially if (as has
Apart from the legion of “hah hah – you’ll need a l-o-n-g exten- been hinted) the technology that Tesla has been developing will be
sion lead” jokes, the only “biggie”, as far as I am concerned, is made available to other manufacturers. Like Nissan?
SC
siliconchip.com.au
June 2015 23
24 Silicon Chip
siliconchip.com.au
TESLA’S POWERWALL:
A Game Changer?
Purely by co-incidence, as we were reviewing and writing about the Tesla
Model S, internet whispers started appearing about a secret new product
being worked on by Tesla. Then came the official word: CEO Elon Musk
would be hosting a major press launch on April 30 to reveal the big secret.
By Ross Tester
B
y the time Elon Musk took to
the stage, the whispers had become a roar – Tesla was about
to release battery backup systems for
home and industry. It was a natural
progression from their work on the
lithium-ion battery packs they’d developed for their electric vehicles but the
detail was all that was left to reveal.
As well as the “live” press launch,
it was also beamed to the world as a
webinar, so wherever you were, you
could see the same message. And the
message was pretty “cool”, at least as
far as Tesla were concerned.
For far too long, we’ve been saddled
with lead-acid batteries as the main
storage for, particularly, solar (PV)
power systems. Lithium-ion batteries
were simply too expensive.
Of course, most installations (at least
here in Australia) don’t have any storage; they’ve been grid-based systems
which fed any excess power back into
the electric power distribution grid.
Those who got in early have been
blessed with very high value feed-in
Tesla CEO Elon Musk launching the PowerWall
and PowerPack (for utilities), April 30 2015.
siliconchip.com.au
June 2015 25
One of Tesla’s 10kWh PowerWalls.
Inside is 350-450V of lithium-ion cells
and a DC/DC converter. It’s about
1300mm high, 860mm across, 180mm
deep and weighs 100kg.
rewards – as much as 66c per kWh.
Those heady days have long gone but
even today, you can put a solar power
system in and reduce your electricity
charges.
But Tesla’s system is rather different
to that. It is intended for either standalone (ie, not grid-connected) systems
or hybrid systems, where there is battery backup as well as grid tie-in.
Musk reasoned that everything
about electricity production, usage
and charges were out of step – the
highest usage was in the morning,
after most people had gone to work,
and in the evening/night, after most
people had come home. Either way,
solar generation is minimal in the early
morning and zero in the night, when
you needed it most. You pay top dollar
for power at these times too.
What if the generation and storage
of electricity could be “time shifted”
- generate the power during the day
when the sun was shining and use it
26 Silicon Chip
during the peak periods mentioned
above. All you would need would be
a storage system capable of doing so!
OK, that’s a bit of an over-simplification but you get the idea!
immediately on announcement. (However the latest news [May 10] is that
production through to the middle of
2016 is sold out – over 38,000 reservations had been received in that time)!
Lead-acid battery
disadvantages
What’s in it?
One of the major reasons for not
using lead-acid batteries for storing
electricity is the cost. Deep-cycle storage batteries are not cheap.
Moreover, they need a lot of maintenance; they emit dangerous hydrogen gas when being charged; they
sometimes leak (and their electrolyte,
acid, is nasty stuff); they’re pretty temperamental about amount and depth of
discharge; they don’t like being overcharged . . . and to top it all off, their
life span can be pretty short (3-5 years
is about average, 10 years exceptional;
indeed, most deep cycle batteries only
have a 2 year guarantee).
Finally, when they have reached
the end of their life, disposal is not as
easy. They can’t be used in landfill,
they can’t be destroyed and even many
recycling centres that used to take
plenty of lead-acid car batteries are
becoming a bit reluctant to take them.
Small wonder that most people with
solar panels on their roofs stayed wellenough away from lead-acid batteries.
Lithium-ion battery
advantages
While there are some parameters
that need monitoring, for the most
part lithium-ion batteries don’t suffer
the disadvantages of lead-acids. They
don’t need much maintenance at all,
they’re much happier about charging
and discharging (mainly because each
cell is monitored and if necessary,
equalised with other cells), they have
a long lifespan (10 years would be
minimum, possibly a lot more) and
they don’t contain volatile materials
so can even be disposed of in landfill.
Or, as we reported in the earlier Tesla
S85 story, they are looking at recycling
as much as 90% of each cell in the
future.
Tesla’s PowerWall
Two (related) products were announced on April 30, the PowerWall
and the Tesla PowerPack. The latter is
intended for large-scale applications.
The first will start shipping shortly
(within a couple of months) – in fact,
Tesla Energy started taking orders
The basic PowerWall comes in
10kWh “weekly cycle” and 7kWh,
“daily cycle” models. Each contains
enough lithium-ion cells to achieve a
350-450V supply. The PowerWall is
designed to attach to a wall, inside or
outside. Overall size of a single PowerWall unit is 1300mm high, 860mm
wide and 180mm deep and weight is
100kg.
Note that there is no DC-to-AC inverter built in but it does have a DC-DC
converter, which means it should be
compatible with solar panels (which
generate DC).
Up to nine PowerWalls can be interconnected to satisfy virtually all
domestic demand.
And the cost?
The daily cyle (7kWh) PowerWall
will sell in the US for $3000; the
10kWh weekly cycle for $3500.
Let’s look at the more expensive one:
in Australia, at current exchange rates
and with GST that will probably sell
for around $5000.
For that, you get a ten year guarantee
and minimal maintenance.
Try buying, say, a 350V deep cycle
lead-acid battery pack with anything
like a 10kWh rating. Because you
can only safely cycle down to, say,
40% you’ll need around 16kWh to
be safe. At the moment, you’re looking at between $20,000 and $25,000.
Invariably, that only gets you a 2-3
year guarantee and it also gets you
all the trials and tribulations that go
with large lead-acid battery installations, not the least of which is a total
replacement after perhaps five years.
Of course, prices are dropping . . .
and Tesla’s PowerWall will have a lot
to do with that!
Other power sources
One of the main reasons that Tesla’s
PowerWall is likely to be a gamechanger is that for the first time, it
makes economic time-shifting power
demands.
Solar panels are not the only means
of charging batteries –wind and smallscale hydro are often mentioned.
But the one which is often forgotten
siliconchip.com.au
PEAK
SOLAR
MORNING DEMAND
EVENING DEMAND
The average home uses more electricity in the morning and
evening than during the day when solar energy is highest.
Tesla’s Powerwall is designed to smooth out these curves.
is the power grid itself. During peak
periods, power charges are high. At
“shoulder” times they’re lower and
during off-peak times they can be
quite low.
Why not use cheap off-peak power
to charge the batteries and either use it
instead of expensive peak power. Or if
you can get a reasonable feed-in tariff,
sell it back to the power companies
during peak times?
We can already hear the screams:
“you can’t get enough feed in tariff any
more to make it worthwhile.”
siliconchip.com.au
Thinking big: Tesla also have plans for power generators
and distributors to use very much larger battery banks to
smooth out their own peak and trough cycles.
Oh yeah? Go for a walk with Dr
Google – you might be surprised to
find that there are now companies in
Australia (not the power companies!)
who will buy stored power from you
at much higher prices than the power
companies offer. They on-sell it to
match peak demand and therefore
peak $$$ – and reward you with the
proceeds (less their commission).
If you think we’re talking cents per
kWh, think again. It can be $/kWh!
It is for all these reasons that we
believe Tesla, and their $5000 lithium-
ion battery, will be a game changer.
Whether you’re using it to go
completely off grid (now very much
cheaper than it was), or putting in a hybrid system; whether you are looking
at solar power or simply time-shifting
cheap off-peak power into peak times,
it’s a whole new ball game.
And the best part? The game has
only just begun!
For more information, visit www.teslaenergy.com – or Google “Tesla Powerwall” and “Tesla Powerpack”
sc
June 2015 27
Artificial vision is becoming a reality
The
BIONIC EYE
Vision is our most important sense, accounting for about 80% of
information received by our brains. The loss of vision can therefore
have a dramatic effect on a person, especially if they lose it through
accident or disease. Now there is promising research on how to
restore a basic sense of vision.
A
Finally, a method of human vision for the blind involving
s with the well-established cochlear implant (“bionic ear”, of which Australia is a world leader) no hardware but just skill is also presented.
which can restore a sense of hearing, there is now
active research on how to restore a basic sense of vision, How the eye works
In nature, ten different types of eye layout can be found.
using an implantable visual prosthesis or “bionic eye”.
So as not to give false expectations, artificial vision does The eye layout found in humans and vertebrate animals,
cephalopods (squid and octopuses) and some spiders most
not provide a visual experience like natural vision.
Bionic vision is a popular theme in science fiction, two resembles a traditional camera.
In this type of eye, called a camera-type eye, light enters
notable examples being Colonel Steve Austin in “The Six
Million Dollar Man” and Lieutenant Commander Geordi through the cornea which acts as a window and also refracts
light like a meniscus lens, contributing two thirds of the
La Forge in “Star Trek: The Next Generation” (see box).
Like many other themes from science fiction, bionic optical power of the eye.
It then passes through the iris which alters its diameter
vision is also becoming a reality – even if the science is
to adjust the amount of light entering the eye, then through
in its infancy.
Apart from implants to restore a sense of vision there the adjustable lens which adjusts its focal length to focus
are also non-implanted prosthetic devices that work on the objects from different distances and then projects an image
principle of sensory substitution whereby the sense of sight onto the light sensitive retina at the back of the eye.
The eye lens also has a graded
is converted into an alternative
optical index (like modern optical
sense such as touch or sound
Part 1 - By Dr David Maddison fibres) for maximum efficiency
and these will also be discussed.
28 Silicon Chip
siliconchip.com.au
and also contributes one third of the optical power of the
eye.
The retina
Being the light-sensitive part of the eye, the retina is also
the part which is often diseased or damaged, leading to a
severe vision deficit or blindness.
The retina is comprised of a number of layers containing
neurons which communicate with each other via synapses.
A neuron is an electrically active cell that can receive inputs, process them and produce an output. An output signal
from a neuron is transmitted to other cells across a synapse
(see SILICON CHIP, “Interfacing to the Brain”, January 2015).
Some neurons are specialised as photoreceptor cells
which are sensitive to light. The two main types of these
specialised neurons are rods and cones. Rods are sensitive
in low light and provide monochrome vision while cone
cells are sensitive to colour and work in bright light. There
are about 100,000,000 rods and 5,000,000 cone cells.
Visual signals from the rods and cones are processed by
other neurons in the retina to reduce the amount of visual
data that has to be sent back to the brain.
One of the ten layers of the retina is the ganglion cell layer.
The rods and cones are connected to this layer via another
type of neuron. The ganglion cells are a type of neuron that
has a very long axon that extends from the eye back into
the brain to form the optic nerve, optic chiasm and optic
tract (see diagram and text below). It is the ganglion cells
that carry information from the retina into the brain. There
are about 1,500,000 ganglion cells.
The axon is the part of the cell body that connects to other
neurons and from which information leaves (See the above
article from SILICON CHIP, January 2015, for discussion of
Ganglion
Cells
Structure of a
human eye.
neurons and axons.)
It is the rods and the cones, the photoreceptor cells which
are most often damaged by disease while the underlying
layers which carry visual information back to the brain
such as the ganglion cell layer are usually left intact. These
remaining layers can be used to introduce visual information to the brain via a prosthetic retinal implant in one
type of bionic eye.
Note from above there are around 105,000,000 rod and
cone cells generating information and only 1,500,000 ganglion cells to convey that information back to the brain.
This lack of a one to one correspondence is suggestive of the
amount of data processing that has occurred in the eye itself.
To complicate matters further, the surface of the retina
is not uniform in its properties or photoreceptor density.
Bipolar Cells (red) Horizontal
Cell
Amacrine Cells (blue)
Photoreceptors
Simplified cross section of a human retina. Counter-intuitively, light enters on the left of the diagram which is the inner
part of the eye. This is the ganglion cell layer which is the connecting circuitry that takes information back to the brain.
The light then travels toward the photoreceptors (rods and cones) which are at the outer part of the eye where light is
converted to signals which are transmitted to the ganglion cells through several layers. This is the opposite arrangement
to an imaging chip in a camera whereby the light sensitive elements are at the light receiving side and the connecting
circuitry is beneath that. In the various layers, points of light from the rods and cones are processed to identify features
such as movement, simple shapes, edges and bright points surrounded by dark points before the information is sent back
to the brain for further processing. Image credit: “Retina layers1”. Licensed under CC BY-SA 3.0 via Wikipedia – http://
en.wikipedia.org/wiki/File:Retina_layers1.gif#/media/File:Retina_layers1.gif
siliconchip.com.au
June 2015 29
Image from the retina, showing higher resolution image
from fovea, the small part of the retina responsible for the
sharpest vision. The brain fills in for the rest of the retina
which produces a less sharp image but is not noticed under
normal circumstances. Frame grab from https://youtu.be/
4I5Q3UXkGd0
The fovea is a small part of the retina, about 1.5mm in
diameter, that is responsible for sharp vision, with a very
high concentration of cone cells. The fovea is connected to
about half of the nerve fibres in the optic nerve while the
rest of the retina connects to the other half.
The fovea represents only about 1% of the retinal surface but uses 50% of the visual cortex, showing its great
importance in sight. Its visual field is small, equivalent
to about two thumbnails at arm’s length so to get a sharp
image of an object the eye has to scan back and forth to
build up an image.
The fovea also only has cone cells so is not sensitive at
night.
The blind spot
You’ll probably remember those biology lessons at school
where a card is moved in and out from one eye and at some
point an “X” on the card disappears. That is caused by the
blind spot, an area where the optic nerve passes through the
retina and no photoreceptors exist. (See www.education.
com/science-fair/article/eye-retinal-blind-spot/).
Normally the brain makes up for the lack of receptors in
that area so its effect is not noticed.
The shape and size of the eye are also important considerations for bionic prostheses. The eye is not spherical
but it is roughly the shape of two hemispherical sections
joined together.
Also, despite people coming in all shapes and sizes, the
size of the eye between different individuals is remarkably
uniform and is around 24mm front to back varying by only
up to 2mm. This means perhaps only one size of visual
prosthetic device that goes in the eye (or replaces it) will
ever need to be manufactured.
It has been estimated that the data bandwidth of the human eye is 8.75Mbits/s. The neurons could fire much faster
giving a much higher speed but there is a trade-off of speed
and energy and data processing efficiency.
A question often asked and which is important for
comparing natural vision to a bionic eye is what is the
resolution of the human eye. It is not simple to answer
that question because unlike a still camera, the eye does
not record a static image.
The eye records a video stream of sorts but the neural
hardware of the eye and brain extract and see only that information that is relevant, somewhat like highly compressed
30 Silicon Chip
video data where only changes in a picture are transmitted.
The question is further complicated by the fact that the
eye and body move and the brain assembles these images
from different viewpoints into a type of composite image
that has more information than the number of photosensitive cells in the eye would suggest (like taking a number of
still images panning across a scene and assembling them
into a larger image).
Taking all of the above into account, one conservative
estimate made by Roger Clark (www.clarkvision.com/
articles/human-eye/) for the resolution of the human eye
is 576 megapixels to view a scene of 120° x 120° but the
real field of view is even larger than this.
Other estimates are that what we see is equivalent to
the high resolution area of the fovea having a 7-megapixel
resolution and the rest of the eye having a resolution of
one megapixels. These issues are discussed in the video
“What Is The Resolution Of The Eye?” https://youtu.
be/4I5Q3UXkGd0
Structure of the visual system
The visual system of an advanced organism such as a
mammal usually consists of the following principal components:
• the eye and its main component containing photo receptors, the retina;
• the optic nerve for relaying information from the retina
to the brain;
• the optic chiasm which causes signals from the optic
nerves to partially cross to allow the visual cortex to
receive a complete visual field from both eyes and then
combine them for stereoscopic vision;
• the lateral geniculate body which has multiple functions
and receives information from the retina via the optic
nerve and optic chiasm and also processes that data
before passing it on via the optic radiations to the visual
cortex where the sense of vision is generated.
Visual system of a human. Note how the visual fields
represented by the green and orange colours start in the
retina, partially cross at the optic chiasm and are finally
mapped onto the visual cortex.
siliconchip.com.au
Even though the eye has the same basic optical elements
as a camera as described above, it is far more than a camera
and a lot of processing of visual data is done inside the
retina itself with numerous different types of neurons involved as well as processing of visual data done elsewhere
in the brain.
Function of the bionic eye
A bionic eye works by stimulating some part of the visual
system in order to generate a sense of vision in cases where
the eye or other components of the visual system are absent,
diseased or defective. As the nervous system and brain use
electric currents to convey information, electrical stimulation is the obvious choice to stimulate the visual system.
Historical background
The use of an electrical current to stimulate vision was
first undertaken in 1755 by Frenchman Charles LeRoy who
passed electricity through the eye of a blind man and this
resulted in the him perceiving the sensation of light.
Following that was the discovery of electrical activity
in animal brains in 1875 but this involved exposing their
brains which was a procedure not amenable to human
experiments. The first EEG or electroencephalograph to
record these brainwaves was taken of a dog in 1914 by
Hans Berger who invented that machine.
At the end of WWI in 1918 the first observations were
made in Germany that electrical stimulation of the surface
of the visual cortex in patients undergoing neurosurgical
procedures under local anaesthesia resulted in the patient
seeing dots of light or “phosphenes”.
In 1924 Hans Berger recorded the first electrical activity
from a human brain with scalp electrodes, a remarkable
achievement at the time given the small voltages involved
and the recording instruments of the time.
Otfrid Foerster in 1929 investigated electrical stimulation
of the occipital lobe (where the visual cortex is located) and
reported that people could see a dot of light. The idea that
many sites could be simultaneously stimulated to provide
vision was postulated by W. Krieg in 1953.
Of course, the complex electronics required to drive
multiple electrode arrays in a portable package would not
be available from some decades not to mention suitable
implant materials.
The measurement of electrical activity in the brain and
its connection to visual processes was thus established
leading to the possibility of artificial vision for the blind
as well as a large array of other possibilities for interfacing
the human brain to machines; see Interfacing to the Brain,
SILICON CHIP, January 2015.
Eye diseases and conditions to be treated
Two common causes or visual impairment or blindness
are among conditions sought to be treated with bionic
vision:
• Age-related macular degeneration is a condition resulting in the loss of central vision leading to the loss
of abilities such as reading, facial recognition, reading
clocks and street signs. Peripheral vision is maintained
although the area of central vision loss gets larger with
time. The fovea, responsible for high resolution vision,
is part of the macula.
• Retinitis pigmentosa is a degenerative condition of the
siliconchip.com.au
The bionic eye in science fiction
The Six Million Dollar Man was a 1973 TV series
which featured a bionic man, Colonel Steve Austin, with
a bionic eye.
What was portrayed as a fantasy 42 years ago, appears
to be within the grasp of current or foreseeable technology.
Also, Star Trek: The Next Generation featured Lieutenant Commander Geordi La Forge with a bionic eye.
Catalog description of The Six
Million Dollar
Man’s bionic
eye.
Screen grabs
from https://
vimeo.com/
77027616
CAD diagram,
very good for
1973 vintage,
showing The Six
Million Dollar
Man’s bionic eye
and interface
circuitry to the
visual cortex.
The bionic
eye of The
Six Million
Dollar Man.
Lieutenant Commander
Geordi La Forge from
Star Trek: The Next
Generation with his
VISOR device (Visual
Instrument and Sensory
Organ Replacement)
that can see most of
the electromagnetic
spectrum. It is
interfaced to his brain
via the optic nerves.
The technology for this
type of device seems
a little further into
the future than that of
The Six Million Dollar
Man’s device.
June 2015 31
Representation of a parked car at different resolutions. In order of increasing resolution these images are 16 (4x4), 64 (8x8),
144 (12x12), 256 (16x16), 1024 (32x32), 4096 (64x64) and 16384 (128x128) pixels. Note that these images indicate the amount
of information that might be conveyed at a particular resolution, not what a person would necessarily see. These images are
also grey scale. Retinal and cortical prostheses currently display phosphenes (pixels) that are either off or on with no shades
or colours. Also, in a current retinal or cortical implant, individual pixels will have space between them. The sensory
substitution device, The vOICe does have 16 shades of “loudness”. (Courtesy Dr Peter Meijer, The vOICe.)
eye due to the loss of photoreceptor cells and an increasing loss of peripheral vision resulting in tunnel vision and
eventual blindness.
In both the above cases, the photoreceptor cells have
died but the neural pathway to the brain remains intact so
in principle, this pathway can be activated with a retinal
implant that stimulates the remaining pathway.
Vision loss due to missing eyes or optic nerve damage
can be treated by stimulation of areas such as the lateral
geniculate body or the visual cortex within the brain.
Ways of interfacing a bionic eye to the brain
Consideration of the anatomy of the human visual system
as described above suggests four ways a bionic eye can
interface to the brain.
An account needs to be made of the fact that the retina
itself processes information and so does the lateral geniculate body and the visual cortex. The further along the visual
pathway one goes before an interface is made it would seem
that the more complicated it would be to make an effective prosthesis as the device might have to generate more
“processed” visual data and less “raw” data.
On the other hand, neuroplasticity, the ability of the
brain to rewire itself might assist in developing a workable
interface to any implanted prosthetic device.
1) As stated above, when disease affects the retina, it
mainly destroys the photoreceptor cells leaving the ganglion cell layer, which transmits data to the brain, intact.
Interfacing a device with this layer would therefore seem
to be an effective way to interface a prosthetic device.
Exceptions are if the retinal disease is so severe that even
ganglion cells are destroyed or there is damage to the optic
nerve. There are several locations within the retina where an
implant can be located. Epiretinal implants are located on
the inner surface of retina, subretinal implants are located
behind the retina and suprachoroidal implants are located
above the choroid and behind the retina.
2) Beyond the ganglion layer of the retina, there is a possibility of interfacing with the optic nerve although this
involves challenges due to accessibility issues and also
interfacing to a thin nerve with around about 1,000,000
nerve fibres.
One such example is the Microsystem-based Visual
Prosthesis (MIVP) which consists of a spiral cuff electrode
wrapped around the optic nerve. Unlike retinal or cortical
implants which produce monochrome phosphenes, coloured phosphenes have been reported in this stimulation
method. Test subjects have also been able to locate and
discriminate between objects.
3) Interfacing to structures such as the lateral geniculate
body deep within the brain is possibly risky and complicated although this is a site being researched for interfacing
a bionic eye.
At the lateral geniculate body the visual data has not yet
been so extensively processed that it has become too complicated to interpret and map. At this point a visual scene
is mapped onto the brain tissue in a relatively simple way
and bears a correspondence to the scene being observed.
It has been estimated that the maximum resolution of an
electrode array implanted at the location would be 40x40
per side.
4) The final interfacing possibility is the primary visual
cortex of the brain (V1) which is close to the surface of the
brain and relatively accessible. This area is specialised for
processing information about stationary and moving objects
and pattern recognition.
The visual image of the retina is mapped onto V1 and a
large portion of that retinal map corresponds to the fovea.
Stimulation of this region of the brain enables a person to
generate points of light (phosphenes) which can be used
to generate a form of vision as has already been shown in
experiments.
A problem with using V1 as an interface is that the
mapping of the retina is not linear so that, say, a square
electrode area would not correspond to the same shape in
the visual field.
The first experiments in artificial vision
The three possible locations of
retinal implants. (Courtesy Bionic Vision Australia.)
32 Silicon Chip
In the early 1960s Giles Brindley and W.S. Lewin in the
UK started researching artificial vision and this resulted
siliconchip.com.au
in 1968 of the implant of 80 electrodes into the visual cortex of a blind person. The experiment was a success and
the subject was able to identify letters and patterns in the
phosphenes that were generated by electrical stimulation
of the 80 electrodes and the research was published in a
classic scientific paper in 1969.
This lead to a major international conference at the University of Chicago which was to establish future directions
for this work.
Giles Brindley’s work inspired numerous similar research
projects in the 1970s with the main objective of assisting
the blind to read with the low resolution image provided
by 80 or so electrodes. Many experiments were done stimulating the visual cortices of volunteers who were having
neurosurgery for other reasons as well as volunteers having
electrode implants.
It soon became less important to assist the blind to read
due to the development of talking books recorded on cassette tape and the emphasis became that of assisting the
blind to navigate in their environment.
This required a portable electronic package to do the
visual processing required to create a usable image on the
implanted electrodes but at the time creating a small portable processing unit was not possible with the electronics
available; this technology would not be available until
the 1990s.
Jeremiah Teehan is credited by the Guinness Book of
Jeremiah Teehan, the man who had the world’s first artificial vision system. Unfortunately, the implant deteriorated
and had to be removed. The cortical implant is shown in
image (a) and an x-ray of the implant in (b) the glasses/
camera combination is shown in (c) and the processing unit
in (d). (From “Organic Bionics”, Wiley-VCH, 2012).
siliconchip.com.au
Records as the first person to have an artificial eye. The device was developed by the late William Dobelle and others.
The record is dated 17th January 2000 and he had 68
platinum electrodes implanted on the surface of the visual
cortex of his brain, although only 20 worked effectively and
gave a narrow field of view, and he wore glasses containing
a camera and an ultrasonic rangefinder as well as a 4.5kg
visual processor unit on a shoulder strap.
He had vision the equivalent of a severely short-sighted
person with 20/400 vision and saw the outline of objects and
letters. Unfortunately the implant deteriorated and had to
be removed. The support electronics could be substantially
miniaturised today.
Another of William Dobelle’s patients, Jens Naumann,
wrote an account of his experience with artificial vision
called “Search for Paradise: A Patient’s Account of the Artificial Vision Experiment”. Also, see the video “Jens Naumann: Artificial Vision” https://youtu.be/JWMYW-SkURI
His implant also deteriorated and he is again blind.
Also see pictures of his implant at www.jensnaumann.
green-first.com/gallery.shtml
Early experiments with bionic vision as described above
involved electrode arrays on the visual cortex but one
alternative approach was to stimulate the retina itself. The
first clinical trial of a 16 electrode retinal implant was
made in 2002 by Second Sight Medical Products: www.2sight.com
What was once only a dream of restoring vision in the
blind has now progressed to a reality today with people
actually using visual prostheses that give them some visual
perception of the world.
Desired resolution
It should be noted that the objective of bionic eye research
is not to provide the equivalent of natural vision as this is
way beyond any technology currently available, but as with
the cochlear implant, it is designed to give a workable, usable replacement for a lost or missing sense which may have
much less fidelity than the natural equivalent but can still
be of tremendous help to the person using the technology.
An important question to answer is: what resolution of
image is usable for a blind person to navigate about the
world, say to walk to shops or catch public transport and
read signs and food labels? This question applies equally
to either a bionic eye or a sensory substitution device.
It has been demonstrated in studies that a resolution
of 32x32 pixels or 1024 pixels is more than enough to
get meaningful and usable images. At lower resolutions a
4x4 array will provide motion detection capability, an approximately 100 electrode array will provide a navigational
capability and an approximately 1,000 electrode array will
provide facial and letter recognition.
A video showing different resolutions of retinal implant
can be seen at https://youtu.be/4gaBAIzAn-M [Project Xense
Retinal Implant Simulation]. Note the separation between
SC
individual pixels.
NEXT MONTH:
In the final part of this mini series, we will look at
some of the amazing advances being made here in
Australia in the quest for the perfect Bionic Eye.
June 2015 33
SILICON
CHIP
.com.au/shop
ONLINESHOP
Looking for a specialised component to build that latest and greatest SILICON CHIP project? Maybe it’s the PCB you’re after.
Or a pre-programmed micro. Or some other hard-to-get “bit”. The chances are they are available direct from the SILICON CHIP ONLINESHOP.
As a service to readers, SILICON CHIP has established the ONLINESHOP. No, we’re not going into opposition with your normal suppliers –
this is a direct response to requests from readers who have found difficulty in obtaining specialised parts such as PCBs & micros.
• PCBs are normally IN STOCK and ready for despatch when that month’s magazine goes on sale (you don’t have to wait for them to be made!).
• Even if stock runs out (eg, for high demand), in most cases there will be no longer than a two-week wait.
• One low p&p charge: $10 per order, regardless of how many boards or micros you order! (Australia only; overseas clients – email us for a postage quote).
• Our PCBs are beautifully made, very high quality fibreglass boards with pre-tinned tracks, silk screen overlays and where applicable, solder masks.
• Best of all, those boards with fancy cut-outs or edges are already cut out to the SILICON CHIP specifications – no messy blade work required!
HERE’S HOW TO ORDER:
4 Via the INTERNET (24 hours, 7 days)
Log on to our secure website: siliconchip.com.au, click on “SHOP” and follow the links
4 Via EMAIL (24 hours, 7 days)
email silicon<at>siliconchip.com.au – Clearly tell us what you want and include your contact and credit card details
4 Via MAIL (24 hours, 7 days)
PO Box 139, Collaroy NSW 2097. Clearly tell us what you want and include your contact and credit card details
4 Via PHONE (9am-5pm, Mon-Fri)
Call (02) 9939 3295 (INT 612 9939 3295) – have your order ready, including contact and credit card details!
SILICON CHIP subscription via any of these methods as well!
Price for any of these micros is just $15.00 each + $10 p&p per order#
PRE-PROGRAMMED MICROS
YES! You can also order or renew your
As a service to readers, SILICON CHIP ONLINESHOP stocks microcontrollers and microprocessors used in new projects (from 2012 on) and some
selected older projects – pre-programmed and ready to fly!
Some micros from copyrighted and/or contributed projects may not be available.
PIC12F675-I/P
PIC16F1507-I/P
PIC16F88-E/P
PIC16F88-I/P
PIC16LF88-I/P
PIC16LF88-I/SO
PIC16F877A-I/P
PIC18F2550-I/SP
PIC18F45K80
PIC18F4550-I/P
PIC18F14K50
UHF Remote Switch (Jan09), Ultrasonic Cleaner (Aug10),
Ultrasonic Anti-fouling (Sep10), Cricket/Frog (Jun12) Do Not Disturb (May13)
IR-to-UHF Converter (Jul13), UHF-to-IR Converter (Jul13)
PC Birdies *2 chips – $15 pair* (Aug13)
Wideband Oxygen Sensor (Jun-Jul12)
Hi Energy Ignition (Nov/Dec12), Speedo Corrector (Sept13),
Auto Headlight Controller (Oct13) 10A 230V Motor Speed Controller (Feb14)
Projector Speed (Apr11), Vox (Jun11), Ultrasonic Water Tank Level (Sep11),
Quizzical (Oct11) Ultra LD Preamp (Nov11), 10-Channel Remote Control
Receiver (Jun13), Revised 10-Channel Remote Control Receiver (Jul13),
Nicad/NiMH Burp Charger (Mar14) Remote Mains Timer (Nov14)
Garbage Reminder (Jan13), Bellbird (Dec13)
LED Ladybird (Apr13)
6-Digit GPS Clock (May-Jun09), Lab Digital Pot (Jul10)
Semtest (Feb-May12)
Batt Capacity Meter (Jun09), Intelligent Fan Controller (Jul10)
USB Power Monitor (Dec12)
GPS Car Computer (Jan10), GPS Boat Computer (Oct10)
USB MIDIMate (Oct11)
PIC18F27J53-I/SP
USB Data Logger (Dec10-Feb11)
PIC18LF14K22
Digital Spirit Level (Aug11), G-Force Meter (Nov11)
PIC32MX795F512H-80I/PT Maximite (Mar11), miniMaximite (Nov11), Colour Maximite (Sept/Oct12),
Touchscreen Audio Recorder (Jun/Jul 14)
PIC32MX170F256B-50I/SP Micromite Mk2 (Jan15) – also includes FREE 47F tantalum capacitor
PIC32MX170F256B-I/SP Low Frequency Distortion Analyser (Apr15) Bad Vibes (June 15)
PIC32MX170F256D-501P/T 44-pin Micromite Mk2 (Now with Mk2 Firmware at no extra cost)
PIC32MX250F128B-I/SP GPS Tracker (Nov13) Micromite ASCII Video Terminal (Jul14)
PIC32MX470F512H-I/PT Stereo Audio Delay/DSP (Nov13), Stereo Echo/Reverb (Feb 14),
Digital Effects Unit (Oct14)
dsPIC33FJ128GP802-I/SP Digital Audio Signal Generator (Mar-May10), Digital Lighting Controller
(Oct-Dec10), SportSync (May11), Digital Audio Delay (Dec11) Level (Sep11)
Quizzical (Oct11), Ultra-LD Preamp (Nov11), LED Musicolor (Nov12)
dsPIC33FJ64MC802-E/P Induction Motor Speed Controller (revised) (Aug13)
dsPIC33FJ128GP306-I/PT CLASSiC DAC (Feb-May 13)
ATTiny861
VVA Thermometer/Thermostat (Mar10), Rudder Position Indicator (Jul11)
ATTiny2313
Remote-Controlled Timer (Aug10)
ATMega48-20AU
Stereo DAC (Sep-Nov09), RGB LED Strip Driver [-20AU chip] (May14)
When ordering, be sure to nominate BOTH the micro required AND the project for which it must be programmed.
SPECIALISED COMPONENTS, SHORT-FORM KITS, ETC
NEW: BAD VIBES INFRASOUND SNOOPER - TDA1543 16-bit Stereo DAC IC (Jun 15) $2.50
BALANCED INPUT ATTENUATOR - all SMD components inc.12 NE5532D ICs, 8 SMD diodes, SMD
caps, polypropylene caps plus all 0.1% resistors (SMD & through-hole)
(May 15) $65.00
APPLIANCE INSULATION TESTER - 600V logic-level Mosfet. 5 x HV resistors: (Apr15) $10.00
ISOLATED HIGH VOLTAGE PROBE - Hard-to-get parts pack:
(Jan15) $40.00
all ICs, 1N5711 diodes, LED, high-voltage capacitors & resistors:
CDI – Hard-to-get parts pack: Transformer components (excluding wire),
all ICs, Mosfets, UF4007 diodes, 1F X2 capacitor:
(Dec 14) $40.00
CURRAWONG AMPLIFIER Hard-to-get parts pack:
(Dec 14) $50.00
LM1084IT-ADJ, KCS5603D, 3 x STX0560, 5 x blue 3mm LEDs, 5 x 39F 400V low profile capacitors
ONE-CHIP AMPLIFIER - All SMD parts
(Nov 14) $15.00
DIGITAL EFFECTS UNIT WM8371 DAC IC & SMD Capacitors [Same components
also suit Stereo Echo & Reverb, Feb14 & Dual Channel Audio Delay Nov 14]
AD8038ARZ Video Amplifier ICs (SMD)
(Oct14)
$25.00
For Active Differential Probe (Pack of 3)
(Sept 14) $12.50
44-PIN MICROMITE Complete kit inc PCB, micro etc
MAINS FAN SPEED CONTROLLER - AOT11N60L 600V Mosfet
RGB LED STRIP DRIVER - all SMD parts and BSO150N03 Mosfets,
(May14)
does not include micro (see above) nor parts listed as “optional”
HYBRID BENCH SUPPLY- all SMD parts, 3 x BCM856DS & L2/L3
(Aug14) $35.00
$5.00
(May14) $20.00
(May 14) $45.00
P&P – $10 Per order#
USB/RS232C ADAPTOR MCP2200 USB/Serial converter IC
NICAD/NIMH BURP CHARGER
(Apr14)
(Mar14)
$7.50
$7.50
10A 230V AC MOTOR SPEED CONTROLLER
(Feb14)
$45.00
GPS Tracker MCP16301 SMD regulator IC and 15H inductor
SMD parts for SiDRADIO
(Nov13) $5.00
(Oct13) $20.00
1 SPD15P10 P-channel logic Mosfet & 1 IPP230N06L3 N-channel logic Mosfet
40A IGBT, 30A Fast Recovery Diode, IR2125 Driver and NTC Thermistor
Same as LF-UF Upconverter parts but includes 5V relay and BF998 dual-gate Mosfet.
RF Probe All SMD parts
(Aug13) $5.00
LF-HF Up-converter Omron G5V-1 5V SPDT 5V relay
(Jun13)
$2.00
“LUMP IN COAX” MINI MIXER SMD parts kit:
(Jun13) $20.00
Includes: 2 x OPA4348AID, 1 x BQ2057CSN, 2 x DMP2215L, 1 x BAT54S, 1 x 0.22Ω shunt
LF-HF UP-CONVERTER SMD parts kit:
(Jun13) $15.00
Includes: FXO-HC536R-125 and SA602AD and all SMD passive components
CLASSiC DAC Semi kit – Includes three hard-to-get SMD ICs:
(Feb-May13) $45.00
CS8416-CZZ, CS4398-CZZ and PLL1708DBQ plus an accurate 27MHz crystal and ten 3mm blue LEDs
with diffused lenses
ISL9V5036P3 IGBT Used in high energy ignition and Jacob’s Ladder (Nov/Dec12, Feb13) $10.00
2.5GHz Frequency Counter
(Dec12/Jan13)
LED Kit: 3 x 4-digit blue LED displays
$15.00
MMC & Choke Kit: ERA-2SM+ Wideband MMC and ADCH-80+ Wideband Choke
$15.00
LOOKING FOR TECHNICAL BOOKS? YOU’LL FIND THE COMPLETE LISTING OF ALL BOOKS AVAILABLE IN THE SILICON CHIP ONLINE BOOKSTORE – ON THE “BOOKS & DVDs” PAGES AT SILICONCHIP.COM.AU/SHOP 06/15
*All items subect to availability. Prices valid for month of magazine issue only. All prices in Australian dollars and included GST where applicable. # P&P prices are within Australia. O’seas? Please email for a quote
PRINTED CIRCUIT BOARDS
PRINTED CIRCUIT BOARD TO SUIT PROJECT:
PUBLISHED:
COMPACT 12V 20W STEREO AMPLIFIER
MAY 2010
PORTABLE STEREO HEADPHONE AMP
APRIL 2011
CHEAP 100V SPEAKER/LINE CHECKER
APRIL 2011
PROJECTOR SPEED CONTROLLER
APRIL 2011
SPORTSYNC AUDIO DELAY
MAY 2011
100W DC-DC CONVERTER
MAY 2011
PHONE LINE POLARITY CHECKER
MAY 2011
20A 12/24V DC MOTOR SPEED CONTROLLER MK2
JUNE 2011
USB STEREO RECORD/PLAYBACK
JUNE 2011
VERSATIMER/SWITCH
JUNE 2011
USB BREAKOUT BOX
JUNE 2011
ULTRA-LD MK3 200W AMP MODULE
JULY 2011
PORTABLE LIGHTNING DETECTOR
JULY 2011
RUDDER INDICATOR FOR POWER BOATS (4 PCBs)
JULY 2011
VOX
JULY 2011
ELECTRONIC STETHOSCOPE
AUG 2011
DIGITAL SPIRIT LEVEL/INCLINOMETER
AUG 2011
ULTRASONIC WATER TANK METER
SEP 2011
ULTRA-LD MK2 AMPLIFIER UPGRADE
SEP 2011
ULTRA-LD MK3 AMPLIFIER POWER SUPPLY
SEP 2011
HIFI STEREO HEADPHONE AMPLIFIER
SEP 2011
GPS FREQUENCY REFERENCE (IMPROVED)
SEP 2011
HEARING LOOP RECEIVER/NECK COUPLER
SEP 2011
DIGITAL LIGHTING CONTROLLER LED SLAVE
OCT 2011
USB MIDIMATE
OCT 2011
QUIZZICAL QUIZ GAME
OCT 2011
ULTRA-LD MK3 PREAMP & REMOTE VOL CONTROL
NOV 2011
ULTRA-LD MK3 INPUT SWITCHING MODULE
NOV 2011
ULTRA-LD MK3 SWITCH MODULE
NOV 2011
ZENER DIODE TESTER
NOV 2011
MINIMAXIMITE
NOV 2011
ADJUSTABLE REGULATED POWER SUPPLY
DEC 2011
DIGITAL AUDIO DELAY
DEC 2011
DIGITAL AUDIO DELAY Front & Rear Panels
DEC 2011
AM RADIO
JAN 2012
STEREO AUDIO COMPRESSOR
JAN 2012
STEREO AUDIO COMPRESSOR FRONT & REAR PANELS
JAN 2012
3-INPUT AUDIO SELECTOR (SET OF 2 BOARDS)
JAN 2012
CRYSTAL DAC
FEB 2012
SWITCHING REGULATOR
FEB 2012
SEMTEST LOWER BOARD
MAR 2012
SEMTEST UPPER BOARD
MAR 2012
SEMTEST FRONT PANEL
MAR 2012
INTERPLANETARY VOICE
MAR 2012
12/24V 3-STAGE MPPT SOLAR CHARGER REV.A
MAR 2012
SOFT START SUPPRESSOR
APR 2012
RESISTANCE DECADE BOX
APR 2012
RESISTANCE DECADE BOX PANEL/LID
APR 2012
1.5kW INDUCTION MOTOR SPEED CONT. (New V2 PCB) APR (DEC) 2012
HIGH TEMPERATURE THERMOMETER MAIN PCB
MAY 2012
HIGH TEMPERATURE THERMOMETER Front & Rear Panels MAY 2012
MIX-IT! 4 CHANNEL MIXER
JUNE 2012
PIC/AVR PROGRAMMING ADAPTOR BOARD
JUNE 2012
CRAZY CRICKET/FREAKY FROG
JUNE 2012
CAPACITANCE DECADE BOX
JULY 2012
CAPACITANCE DECADE BOX PANEL/LID
JULY 2012
WIDEBAND OXYGEN CONTROLLER MK2
JULY 2012
WIDEBAND OXYGEN CONTROLLER MK2 DISPLAY BOARD JULY 2012
SOFT STARTER FOR POWER TOOLS
JULY 2012
DRIVEWAY SENTRY MK2
AUG 2012
MAINS TIMER
AUG 2012
CURRENT ADAPTOR FOR SCOPES AND DMMS
AUG 2012
USB VIRTUAL INSTRUMENT INTERFACE
SEPT 2012
USB VIRTUAL INSTRUMENT INT. FRONT PANEL
SEPT 2012
BARKING DOG BLASTER
SEPT 2012
COLOUR MAXIMITE
SEPT 2012
SOUND EFFECTS GENERATOR
SEPT 2012
NICK-OFF PROXIMITY ALARM
OCT 2012
DCC REVERSE LOOP CONTROLLER
OCT 2012
LED MUSICOLOUR
NOV 2012
LED MUSICOLOUR Front & Rear Panels
NOV 2012
CLASSIC-D CLASS D AMPLIFIER MODULE
NOV 2012
CLASSIC-D 2 CHANNEL SPEAKER PROTECTOR
NOV 2012
HIGH ENERGY ELECTRONIC IGNITION SYSTEM
DEC 2012
USB POWER MONITOR
DEC 2012
1.5kW INDUCTION MOTOR SPEED CONTROLLER (NEW V2 PCB) DEC 2012
THE CHAMPION PREAMP and 7W AUDIO AMP (one PCB) JAN 2013
GARBAGE/RECYCLING BIN REMINDER
JAN 2013
2.5GHz DIGITAL FREQUENCY METER – MAIN BOARD
JAN 2013
2.5GHz DIGITAL FREQUENCY METER – DISPLAY BOARD
JAN 2013
2.5GHz DIGITAL FREQUENCY METER – FRONT PANEL
JAN 2013
SEISMOGRAPH MK2
FEB 2013
MOBILE PHONE RING EXTENDER
FEB 2013
GPS 1PPS TIMEBASE
FEB 2013
LED TORCH DRIVER
MAR 2013
NOTE: The listings below are for the PCB only – not a full kit. If you want a kit, contact the kit suppliers advertising in this issue.
For more unusual projects where kits are not available, some have specialised components available – see the list opposite.
PCB CODE:
Price:
01104101
$7.50
01104111 $10.00
04104111 $10.00
13104111 $10.00
01105111 $30.00
11105111 $15.00
12105111 $10.00
11106111 $20.00
07106111 $20.00
19106111 $25.00
04106111 $10.00
01107111 $25.00
04107111 $20.00
20107111-4 $80 per set
01207111 $20.00
01108111 $10.00
04108111 $10.00
04109111 $20.00
01209111
$5.00
01109111 $25.00
01309111 $20.00
04103073 $30.00
01209101 $10.00
16110111 $30.00
23110111 $25.00
08110111 $25.00
01111111 $30.00
01111112 $20.00
01111113 $10.00
04111111 $20.00
07111111 $10.00
18112111
$5.00
01212111 $25.00
01212112/3 $20 per set
06101121 $10.00
01201121 $30.00
0120112P1/2 $20.00
01101121/2 $30 per set
01102121 $20.00
18102121
$5.00
04103121 $40.00
04103122 $40.00
04103123 $75.00
08102121 $10.00
14102112 $20.00
10104121 $10.00
04104121 $20.00
04104122 $20.00
10105122 $35.00
21105121 $30.00
21105122/3 $20 per set
01106121 $20.00
24105121 $30.00
08109121 $10.00
04106121 $20.00
04106122 $20.00
05106121 $20.00
05106122 $10.00
10107121 $10.00
03107121 $20.00
10108121 $10.00
04108121 $20.00
24109121 $30.00
24109122 $30.00
25108121 $20.00
07109121 $20.00
09109121 $10.00
03110121
$5.00
09110121 $10.00
16110121 $25.00
16110121 $20 per set
01108121 $30.00
01108122 $10.00
05110121 $10.00
04109121 $10.00
10105122 $35.00
01109121/2 $10.00
19111121 $10.00
04111121 $35.00
04111122 $15.00
04111123 $45.00
21102131 $20.00
12110121 $10.00
04103131 $10.00
16102131
$5.00
PRINTED CIRCUIT BOARD TO SUIT PROJECT:
PUBLISHED:
PCB CODE:
Price:
CLASSiC DAC MAIN PCB
APR 2013
01102131 $40.00
CLASSiC DAC FRONT & REAR PANEL PCBs
APR 2013
01102132/3 $30.00
GPS USB TIMEBASE
APR 2013
04104131 $15.00
LED LADYBIRD
APR 2013
08103131
$5.00
CLASSiC-D 12V to ±35V DC/DC CONVERTER
MAY 2013
11104131 $15.00
DO NOT DISTURB
MAY 2013 12104131 $10.00
LF/HF UP-CONVERTER
JUN 2013 07106131 $10.00
10-CHANNEL REMOTE CONTROL RECEIVER
JUN 2013 15106131 $15.00
IR-TO-455MHZ UHF TRANSCEIVER
JUN 2013 15106132 $7.50
“LUMP IN COAX” PORTABLE MIXER
JUN 2013
01106131 $15.00
L’IL PULSER MKII TRAIN CONTROLLER
JULY 2013
09107131 $15.00
L’IL PULSER MKII FRONT & REAR PANELS
JULY 2013
09107132/3 $20.00/set
REVISED 10 CHANNEL REMOTE CONTROL RECEIVER
JULY 2013
15106133 $15.00
INFRARED TO UHF CONVERTER
JULY 2013
15107131 $5.00
UHF TO INFRARED CONVERTER
JULY 2013
15107132 $10.00
IPOD CHARGER
AUG 2013
14108131
$5.00
PC BIRDIES
AUG 2013
08104131 $10.00
RF DETECTOR PROBE FOR DMMs
AUG 2013
04107131 $10.00
BATTERY LIFESAVER
SEPT 2013
11108131
$5.00
SPEEDO CORRECTOR
SEPT 2013
05109131 $10.00
SiDRADIO (INTEGRATED SDR) Main PCB
OCT 2013
06109131 $35.00
SiDRADIO (INTEGRATED SDR) Front & Rear Panels
OCT 2013
06109132/3 $25.00/pr
TINY TIM AMPLIFIER (same PCB as Headphone Amp [Sept11]) OCT 2013 01309111 $20.00
AUTO CAR HEADLIGHT CONTROLLER
OCT 2013
03111131 $10.00
GPS TRACKER
NOV 2013
05112131 $15.00
STEREO AUDIO DELAY/DSP
NOV 2013
01110131 $15.00
BELLBIRD
DEC 2013
08112131 $10.00
PORTAPAL-D MAIN BOARDS
DEC 2013 01111131-3 $35.00/set
(for CLASSiC-D Amp board and CLASSiC-D DC/DC Converter board refer above [Nov 2012/May 2013])
LED Party Strobe (also suits Hot Wire Cutter [Dec 2010])
JAN 2014
16101141
$7.50
Bass Extender Mk2
JAN 2014
01112131 $15.00
Li’l Pulser Mk2 Revised
JAN 2014
09107134 $15.00
10A 230VAC MOTOR SPEED CONTROLLER
FEB 2014 10102141 $12.50
NICAD/NIMH BURP CHARGER
MAR 2014
14103141 $15.00
RUBIDIUM FREQ. STANDARD BREAKOUT BOARD
APR 2014
04105141 $10.00
USB/RS232C ADAPTOR
APR 2014 07103141 $5.00
MAINS FAN SPEED CONTROLLER
MAY 2014 10104141 $10.00
RGB LED STRIP DRIVER
MAY 2014
16105141 $10.00
HYBRID BENCH SUPPLY
MAY 2014 18104141 $20.00
2-WAY PASSIVE LOUDSPEAKER CROSSOVER
JUN 2014 01205141 $20.00
TOUCHSCREEN AUDIO RECORDER
JUL 2014 01105141 $12.50
THRESHOLD VOLTAGE SWITCH
JUL 2014 99106141 $10.00
MICROMITE ASCII VIDEO TERMINAL
JUL 2014 24107141 $7.50
FREQUENCY COUNTER ADD-ON
JUL 2014 04105141a/b $15.00
VALVE SOUND SIMULATOR PCB
AUG 2014 01106141 $15.00
VALVE SOUND SIMULATOR FRONT PANEL (BLUE)
AUG 2014 01106142 $10.00
TEMPMASTER MK3
AUG 2014 21108141 $15.00
44-PIN MICROMITE
AUG 2014 24108141 $5.00
OPTO-THEREMIN MAIN BOARD
SEP 2014 23108141 $15.00
OPTO-THEREMIN PROXIMITY SENSOR BOARD
SEP 2014 23108142
$5.00
ACTIVE DIFFERENTIAL PROBE BOARDS
SEP 2014
04107141/2 $10/set
MINI-D AMPLIFIER
SEP 2014 01110141 $5.00
COURTESY LIGHT DELAY
OCT 2014 05109141 $7.50
DIRECT INJECTION (D-I) BOX
OCT 2014 23109141 $5.00
DIGITAL EFFECTS UNIT
OCT 2014 01110131 $15.00
DUAL PHANTOM POWER SUPPLY
NOV 2014
18112141 $10.00
REMOTE MAINS TIMER
NOV 2014
19112141 $10.00
REMOTE MAINS TIMER PANEL/LID (BLUE)
NOV 2014 19112142 $15.00
ONE-CHIP AMPLIFIER
NOV 2014 01109141 $5.00
TDR DONGLE
DEC 2014
04112141
$5.00
MULTISPARK CDI FOR PERFORMANCE VEHICLES
DEC 2014
05112141 $10.00
CURRAWONG STEREO VALVE AMPLIFIER MAIN BOARD
DEC 2014
01111141 $50.00
CURRAWONG REMOTE CONTROL BOARD
DEC 2014
01111144
$5.00
CURRAWONG FRONT & REAR PANELS
DEC 2014
01111142/3 $30/set
CURRAWONG CLEAR ACRYLIC COVER
JAN 2015
- $25.00
ISOLATED HIGH VOLTAGE PROBE
JAN 2015
04108141 $10.00
SPARK ENERGY METER MAIN BOARD
FEB/MAR 2015
05101151 $10.00
SPARK ENERGY ZENER BOARD
FEB/MAR 2015
05101152 $10.00
SPARK ENERGY METER CALIBRATOR BOARD
FEB/MAR 2015
05101153
$5.00
APPLIANCE INSULATION TESTER
APR 2015
04103151 $10.00
APPLIANCE INSULATION TESTER FRONT PANEL
APR 2015
04103152 $10.00
LOW-FREQUENCY DISTORTION ANALYSER
APR 2015
04104151
$5.00
APPLIANCE EARTH LEAKAGE TESTER PCBs (2)
MAY 2015 04203151/2 $15.00
APPLIANCE EARTH LEAKAGE TESTER LID/PANEL
MAY 2015
04203153 $15.00
BALANCED INPUT ATTENUATOR MAIN PCB
MAY 2015
04105151 $15.00
BALANCED INPUT ATTENUATOR FRONT & REAR PANELS
MAY 2015
04105152/3 $20.00
4-OUTPUT UNIVERSAL ADJUSTABLE REGULATOR
MAY 2015
18105151
$5.00
NEW THIS MONTH
SIGNAL INJECTOR & TRACER
PASSIVE RF PROBE
SIGNAL INJECTOR & TRACER SHIELD
BAD VIBES INFRASOUND SNOOPER
CHAMPION + PRE-CHAMPION
JUNE 2015
JUNE 2015
JUNE 2015
JUNE 2015
JUNE 2015
04106151
04106152
04106153
04104151
01109121/2
$7.50
$2.50
$5.00
$5.00
$7.50
By Nicholas Vinen
The
Bad Vibes
Infrasound Snooper
Back in March 2013 we published the Infrasound Detector for
low frequency measurements. Now you can “listen” to low
frequency vibrations with our Infrasound Snooper. It frequency
shifts and amplitude modulates a frequency range of about 1Hz
to 20Hz by about five or six octaves so that you can listen directly
to wind turbines or elephants, crocodiles and other animals that
communicate with infrasound.
O
UR INFRASOUND SNOOPER uses
Digital Signal Processing (DSP)
techniques in a PIC32MX170 microcontroller, an electret microphone,
a DAC chip, a TL074 quad op amp
and very little else, to drive a pair of
headphones.
High levels of infrasound can have
a negative impact on your health but
you might not even know when you
are being exposed to low frequency vibrations unless they excite harmonics
by rattling window panes and similar,
because they’re otherwise inaudible.
In January this year, a study by acous36 Silicon Chip
tics expert Steven Cooper of Bridgewater Acoustics attracted a great deal
of controversy over its findings which
support the notion that infrasound
from wind turbines can cause negative health impacts on people some
distance away.
At the SILICON CHIP offices, some of
our staff recently experienced ill effects, including headaches and nausea,
when a ground compacting machine
was operating on a nearby building
site. It evidently set up all sorts of
standing waves in our building, as it
moved around the construction site.
Some “nodes” in our building were
quite unpleasant places to be.
So if you are living or working near
potential sources of infrasound and are
suffering from some of the potential
symptoms, our Infrasound Snooper
can certainly help.
Our Infrasound Detector (SILICON
CHIP, March 2013) allows you to measure the amplitude and frequency of
infrasonic sound waves but the results
can be somewhat difficult to interpret
since you cannot hear the phenomenon. The Infrasound Snooper lets you
assess the amplitude and frequency of
siliconchip.com.au
Scope1: amplified infrasound output from IC2c (green) and
the modulated signal to the headphones (yellow) for a lowfrequency impulse of about 10Hz. The mode is AM+FM
with low-frequency boost and you can see the output freq
uency shifting for the positive/negative infrasound signal as
well as the delay from the low-frequency boosting filter.
Scope2: a similar impulse at a longer timebase than Scope1
(50ms/div rather than 20ms/div). The mode is AM+FM
without low-frequency boost and thus the output waveform
modulation corresponds very closely to the green input
signal excursions. As before, positive excursions produce
higher modulated frequencies than negative excursions.
the waves but importantly, you can
also hear the details – whether they
are short, repetitive bursts, continuous waves or somewhere in between.
Our Infrasound Snooper is housed in
a small plastic box and uses a doublesided PCB (code 04104151) measuring
104 x 60.5mm. An electret microphone
is mounted at one end of the case and a
rotary switch on the lid offers a number
of different listening modes.
Circuit description
Fig.1 shows the circuit details.
Infrasonic sound waves are sensed
with the electret microphone (MIC1)
or an external microphone plugged
into CON4. A 6.8kΩ pull-up resistor
from the 5V regulated rail provides the
electret’s operating current.
The electret signal is AC-coupled via
a 1µF capacitor to the non-inverting
input of op amp IC2b, one section of
a TL074 quad JFET-input op amp. In
conjunction with the 1MΩ resistor, this
capacitor forms a low pass filter with a
-3dB corner frequency at 0.2Hz. Thus
signals above 0.5Hz pass through with
little or no attenuation. The 5V rail is
used as a convenient DC bias point, to
bring the signal within IC2’s supply
rails, ie, roughly half-way between 0V
and VCC which is typically 8.7V.
IC2b operates as a simple buffer,
feeding the following third-order active low-pass filter based around op
amp stage IC2a which has a gain of two
siliconchip.com.au
Features & Specifications
• Converts infrasonic sound waves into audible waves via frequency shift modulation
• Minimal delay between detection of infrasound and audible response; essentially
real-time
• Output volume proportional to infrasonic wave amplitude
• Output pitch deviation indicates infrasonic wave polarity
• Optional digital filter to compensate for typical low-frequency microphone roll-off
• Quick response time allows listener to determine nature of infrasound (pulsed,
continuous, etc) as well as frequency and amplitude
• Operating input frequency range: approximately 1-20Hz
• Power supply: 9V battery, ~60mA current drain (9-15V DC plugpack can also be
used)
• Five modes: AM+FM with or without microphone response compensation, AM only
with or without microphone response compensation, FM only (fixed amplitude)
June 2015 37
CON1
D1 1N400 4
22Ω
6-12V
DC/AC
POWER
A
1 ON/OFF
2
3
S1b
K
4
D2 1N 5819
A
+
Vcc
K
6
100k
5
9V
BATTERY
Vcc
+5V
+5V
VR2
10k
22k
+3.3V
IC2: TL074
6.8k
1M
470Ω
100nF
470nF
1 µF
5
4
IC2b
6
7
2.2M
470nF
22k
22k
2
22k
INPUT
22pF
9
6.2k
3
IC2a
1
10
IC2c
47k
1 µF
8
6.8k
11
MODE
1 SELECT
2
3
2.2M
470nF
+
MIC1
CON4
4
S1a
ELECTRET
6
5
SWITCH S1 SETTINGS
1:
2:
3:
4:
5:
6:
OFF
AM+FM+BOOST
AM+FM
AM+BOOST
AM
FM
CON3
ICSP
10k
1
2
3
4
5
SC
20 1 5
INFRASOUND SNOOPER
Fig.1: the complete circuit diagram. The infrasound is picked up by an electret microphone & then buffered, filtered &
amplified by IC2b-IC2a before being fed to microcontroller IC1. IC1 digitises the signal & carries out the necessary signal
processing before feeding it to DAC IC3. IC3 then feeds gain stage IC2d which in turn drives the output socket (CON5).
(set by the pair of 22kΩ resistors at its
pin 2). The filter is a Butterworth type
which is pretty much flat from DC up
to 20Hz, with gain rapidly falling off
at higher frequencies.
This is important since we need to
apply a fair bit of gain to the infrasonic
signals to scale them to an appropriate
level for the microcontroller’s ADC
(~1V RMS). Op amp IC2c provides the
requisite gain which is variable using
VR2. So the gain ranges from a minimum of 6x (47kΩ ÷ (10kΩ + 470Ω) + 1)
to a maximum of around 100x (47kΩ
÷ (470Ω + W) + 1, where W is VR2’s
wiper resistance). Thus VR2 acts as the
unit’s sensitivity adjustment.
38 Silicon Chip
The signal must then have its DC
bias shifted to suit the PIC32MX
microcontroller’s ADC, which runs
from a 3.3V regulated rail. Thus it is
AC-coupled with a 1µF capacitor and
biased with a pair of 2.2MΩ resistors
forming a voltage divider between the
3.3V rail and ground. This sets the DC
level at pin 2 of IC1 at around 1.65V.
The 6.8kΩ resistor protects IC1 from
high voltages from IC2 during powerup, power-down and high signal
excursions.
IC1 digitises the signal and then
applies some DSP-based filtering to
correct for low-frequency roll-off due
to the two coupling stages and the
microphone’s response. To create an
audible signal, the infrasound signal
is rectified and then used to amplitude
modulate a sinewave at about 200Hz.
Some frequency modulation is normally also applied to this waveform,
based on the pre-rectification signal.
This allows the polarity of infrasonic
excursions to be distinguished, based
on the difference in resulting signal
frequency.
This modulated signal appears in
digital (I2S) format at pins 5, 7 & 25 of
IC1. The serial audio data is produced
at pin 5 (RB1) which is mapped to one
of the two internal SPI peripherals so
that the data stream is uninterrupted.
siliconchip.com.au
REG1 78L05
Vcc
+5V
OUT
IN
REG2
MCP1700-3.3/TO
GND
GND
IN
100 µF
100nF
16V
25V
78L05
GND
100 µF
220 µF
+3.3V
OUT
IN
OUT
16V
33k
MC P1700
IN
GND
OUT
+5V
+3.3V
LEDS
10Ω
470Ω
MMC
MMC
13
3
2
VDD
AVDD
RA1/AN1/VREF–
SOSCO/RA4
RA0 /AN 0 /VREF+
PGED1/AN2/RB 0
10
9
6
AN 10 /RB1 4
SOSCI/RB4
AN11/RB13
RA3/CLKO
AN12/RB12
RA2/CLKI
PGEC2/RB11
RB2/AN4
IC1
PIC32MX170PIC3
2 MX170F256B
PGED2/RB10
TD0/RB9
TCK/RB8
TDI/RB7
1
14
15
AN5/RB3
12
LOW
BATTERY/
OPERATE
PGEC1/AN3/RB1
VCAP
PGEC3/RB6
λ LED2
CLIP
K
D1, D2
A
4
K
26
25
24
100nF
23
MMC
22
21
18
1
17
16
2
7
3
MCLR
PGED3/RB5
K
A
A
λ LED1
K
28
AN9/RB15
11
A
100nF
100nF
1k
BitCLK
W Sel
DATA
5
Vdd
IC3
TDA1 5 43
GND
4
AoutR
VrefO
AoutL
8
7
6
12
13
5
IC2d
100 µF
16V
680Ω
4.7nF
20
14
VR3
1k
VSS
19
VSS
8
This data is clocked by a signal from
pin 25 (RB14/SCK1). The left/right
“word” clock is produced at pin 7
(RB3), also by the SPI peripheral, using
its audio framing feature.
These three signals pass to IC3, a
TDA1543 16-bit oversampling DAC.
We’ve used this chip for a number of
reasons: it’s available in an 8-pin DIL
package which is easy to solder; it runs
from a single 5V rail; it’s quite cheap;
it’s easy to interface to and its audio
performance is respectable.
Its outputs at pins 6 & 8 are current
sink stages and since we only need
a mono signal, they are simply connected together, filtered (to remove
siliconchip.com.au
OUTPUT
2
1
5
CON5
10 µF
AVSS
27
4
3
6.3V
TANT.
OR SMD
CERAMIC
the digital aliasing artefacts) and
converted to a voltage by remaining
op amp IC2d. The 680Ω resistor sets
the output voltage swing.
IC2d’s pin 12 non-inverting input
is connected to the 2.2V reference
voltage which sets the DC level of the
resulting signal. The Vref (pin 7) of IC3
has a dual purpose; the current drawn
from this pin is internally amplified
and added to the current sink by the
left & right output pins. However, in
this case, the circuit works best with
no extra current sink, hence there is
no load on the Vref pin.
The DC in the output of IC2d is
blocked by a 100µF electrolytic capaci-
tor and biased to ground by the track
of VR3, the volume potentiometer.
The headphones or earphones are
connected to its wiper via CON5 with
no extra buffering. This is a relatively
crude system but it works well enough.
The main purpose is to allow the user
to reduce the output to a comfortable
level when used in conjunction with
sensitive earphones.
Power supply
The Infrasound Snooper is designed
to run off a 9V battery but a 9-15V
DC plugpack could also be used. The
supply current therefore flows through
one of two reverse-polarity protection
June 2015 39
1 µF
CON4
S
MIC1
VR2 10k
Clip
1k
LED1
LED2 A
Batt
VR3 1k
INPUT
+
10 µF
PIC32MX170F256B
IC1
1
100nF
ICSP
2.2M
2.2M
+
10Ω
33k
6.8k
22Ω
100 µF
470Ω
5819
D1
REG2 +
100nF
CON3
100nF
REG1
470Ω
1M
4004
Power/Mode
A
T
10k
D2
220 µF
+
47k
100 µF
+
6.8k
R
S1
+
100nF
Snooper
IC3
100nF
22pF
470nF
9V 0V
100k
C 2015
TDA1543
4.7nF
680Ω
22k
22k
22k
6.2k
22k
+
Infrasonic
CON1
1 µF
IC2 TL074
470nF
ELECTRET
MIC
INSERT
470nF
04104151
9V BATTERY
R
100 µF
CON5
S
T
OUTPUT
(BLUE OUTLINES REPRESENT
COMPONENTS NOT USED
IN THIS PROJECT)
Fig.2: follow this parts layout diagram to build the PCB. Take care to ensure that all polarised parts are correctly
orientated and use a socket for microcontroller IC1. Sockets are optional for IC2 & IC3.
diodes, D1 for the plugpack or D2 for
the battery. D2 is a Schottky diode, to
minimise voltage drop and therefore
extend battery life.
Rotary switch S1 acts as both the
power and mode switch. One pole connects the power supply directly to IC2
as well as to the input of REG1. This
regulator provides the 5V rail for DAC
IC3, the electret supply and for signal
biasing in the input filter. It also feeds
REG2, a 3.3V low-dropout regulator
which powers microcontroller IC1.
The other pole of S1 is connected to
pins 6, 9, 10 & 11 of IC1 which are configured as inputs with internal pull-up
currents enabled. Thus IC1 can sense
which position S1 is in by determining
which of these inputs is pulled low. If
none are then the switch must be in the
second position, as the circuit is not
powered in the first position.
IC1 monitors the battery voltage via
a 4:1 divider (100kΩ/33kΩ), digitising the resulting voltage at its AN1
analog input (pin 3). If the battery
voltage is low (<7V), it illuminates
the low-battery LED (LED2) via its pin
12 output (RA4). The 470Ω currentlimiting resistor sets the LED current
to around 2-3mA.
Similarly, IC1 can light LED1 if
there is an input signal overload, using
its pin 4 output. The red LED is a little
more efficient so operates at a lower
current, with a 1kΩ current-limiting
resistor resulting in around 1-1.5mA
flowing.
40 Silicon Chip
CON3 is a programming header for
IC1 (if required) with a 10kΩ pullup resistor on its MCLR pin (pin 1)
preventing unexpected reset events.
IC1’s analog supply at pin 28 is lowpass filtered with a 10Ω resistor and
100nF bypass capacitor, while a 10µF
capacitor at pin 20 is required for its
internal core regulator.
Construction
All the parts except for the electret
microphone are mounted on a doublesided PCB coded 04104151 (104 x
60.5mm). This can be clipped into a
standard UB3 jiffy box.
Fig.2 shows the parts layout on the
PCB. Start by fitting the fixed resistors. Table 1 shows the resistor colour
codes, although it’s better to check the
values using a DMM. Note that since
the same PCB was used for the Low
Frequency Distortion Analyser, there
are a number of component positions
which are not populated (including
some resistor locations).
Diodes D1 & D2 can go in next, noting that D1 is a 1N4004 while D2 is a
1N5819. Be sure to orientate them correctly, with their striped cathode ends
towards the bottom edge of the PCB.
Follow with the IC socket(s). It’s a
good idea to use a socket for microcontroller IC1 but they are not really
necessary for IC2 & IC3. Instead, IC2 &
IC3 can be soldered directly to the PCB
for greater long-term reliability. Either
way, make sure that the pin 1 notch/
dot of each IC goes towards the top of
the board. This is especially critical if
soldering the ICs in without sockets
since you can’t easily remove them
once they’re in!
The two jack sockets are next on the
list, followed by the ceramic and MKT
capacitors. REG1 & REG2 can then
go in but be careful not to get them
mixed up as they look similar. Their
leads will need to be cranked out using needle nose pliers to suit the pad
spacing on the PCB.
Now solder the DC socket in place,
followed by the electrolytic capacitors.
Be sure to orientate the electros correctly, with the longer (positive) leads
towards the top edge of the PCB (see
Fig.2). If using a tantalum type rather
than an SMD ceramic for the 10µF
capacitor, it too is polarised and can
go in now.
Now fit the two 9mm potentiometers. They’re different values so don’t
get them mixed up (the 1kΩ pot may
be marked “102” and the 10kΩ pot
“103”). The polarised 3-pin header
(for the microphone) can then be fitted with its keyway tab orientated as
shown.
The battery snap is next. Pass its
leads through the two strain relief
holes before soldering its leads to their
respective pads on the top of the PCB
as shown in Fig.2. You can then pull
the leads back through the holes to
reduce the slack. Note that they will
probably be a tight fit, to provide the
siliconchip.com.au
Table 2: Capacitor Codes
Value
1µF
470nF
100nF
4.7nF
22pF
IEC Code EIA Code
1u0
105
470n
474
100n
104
4n7
472
22p
22
of the cable, then carefully solder
and crimp the leads at one end to the
header crimp pins. That done, the
crimp pins can be slid into the header
(the tang goes into the narrow channel)
until they lock into position.
The next step is to determine which
lead on the electret microphone is the
positive and which is the negative.
This may be marked but if not, use
your DMM (set to ohms) to determine
which lead is connected to the case –
this is the negative (ground) lead.
Next, slip 5mm-lengths of 3mmdiameter heatshrink over the insulation at the end of the cable leads, then
solder these two leads to the microphone. Make sure that the positive lead
from the header goes to the electret
positive (the positive side is marked
on the PCB, adjacent to CON4).
Once the two leads have been soldered, slip the heatshrink sleeves over
the solder connections and shrink
them down to provide strain relief
(see photo).
This view shows the completed PCB assembly. Note how the battery snap leads
are looped through strain relief holes before being soldered to the top of the PCB.
necessary strain relief.
The two 3.5mm switched jack
sockets (CON4 & CON5) can now be
mounted. Check that they sit flush
against the PCB before soldering their
pins. CON3, the ICSP header, can then
go in but can be omitted if you’re using
a pre-programmed microcontroller.
Rotary switch S1 is mounted after
first cutting its shaft so that it’s 30mm
long, as measured from the top surface
of the main body. This can be done using a hacksaw and the end of the shaft
then cleaned up with a file to remove
any burrs. It must be installed with
its polarity-indicating plastic post
orientated as shown on Fig.2 (ie, at the
three o’clock position). Again, make
µF Value
1µF
0.47µF
0.1µF
.0047µF
NA
sure it’s pushed down flat against the
board before soldering its pins.
Finally, solder the two LEDs in
place. The longer leads are the anodes
and go into the pads indicated with
“A” on Fig.2. Tack solder these in place
at full lead length; you can adjust the
height and solder them properly once
the box has been prepared.
Microphone cable
The next job is to make up a cable to
connect the microphone. That’s done
using a 70mm length of light-duty
Fig.8 cable which is terminated at one
end in a 2-way polarised header.
Begin by removing about 3mm of
insulation from the leads at each end
Testing
If using sockets, plug in the ICs,
with their pin 1 dot or notch aligned
as shown in Fig.2. If IC1 hasn’t already
been programmed (you can buy a pro-
Table 1: Resistor Colour Codes
o
o
o
o
o
o
o
o
o
o
o
o
o
o
o
siliconchip.com.au
No.
2
1
1
1
1
4
1
2
1
1
1
2
1
1
Value
2.2MΩ
1MΩ
100kΩ
47kΩ
33kΩ
22kΩ
10kΩ
6.8kΩ
6.2kΩ
1kΩ
680Ω
470Ω
22Ω
10Ω
4-Band Code (1%)
red red green brown
brown black green brown
brown black yellow brown
yellow violet orange brown
orange orange orange brown
red red orange brown
brown black orange brown
blue grey red brown
blue red red brown
brown black red brown
blue grey brown brown
yellow violet brown brown
red red black brown
brown black black brown
5-Band Code (1%)
red red black yellow brown
brown black black yellow brown
brown black black orange brown
yellow violet black red brown
orange orange black red brown
red red black red brown
brown black black red brown
blue grey black brown brown
blue red black brown brown
brown black black brown brown
blue grey black black brown
yellow violet black black brown
red red black gold brown
brown black black gold brown
June 2015 41
(UB3 BOX LID)
A
CL
25.75
5
5
B
B
CL
HOLE SIZES: HOLE A 6.5mm DIAM, HOLES B 3.0mm DIAM
HOLES C 6.0mm DIAM, HOLES D 8.0mm DIAM
19
22
D
22
D
C
C
24
13.5
13.5
24
(FRONT SIDE OF UB3 BOX)
ALL DIMENSIONS IN MILLIMETRES
SILICON
CHIP
AM+Boost
AM+FM
AM+FM+Boost
AM
FM
Off
BAD VIBES
Infrasound Snooper
Overload
Ext. Mic
Gain
On/Low Battery
Vol.
Output
Fig.4: this front panel artwork can be copied and used direct or a PDF version
can be downloaded from the SILICON CHIP website & printed onto photo paper or
onto Datapol/Dataflex label paper.
grammed micro from the SILICON CHIP
Online Shop), do it now via CON3.
External power can be supplied from
the programmer (eg, a PICkit 3).
Once all the ICs are in place, you
can test the unit as follows:
(1) Rotate S1 to the off position (fully
anti-clockwise), then connect the
battery.
42 Silicon Chip
(2) Rotate S1 one step clockwise and
check that the yellow LED flashes
briefly, then periodically.
(3) Turn VR2 & VR3 all the way down
and connect a pair of headphones or
earphones to the unit.
(4) Turn VR2 & VR3 up slowly and
blow on the microphone insert. After
turning the pots up sufficiently, you
Fig.3 (left): use this full-size template
to drill the holes in the lid and front
side of the UB3 case.
should hear the modulated signal from
the low frequency components of this
sound. With the gain up high, if you
blow hard enough, the overload (red)
LED may light.
(5) Switch S1 to the other positions
and check that the sound produced
by the unit changes.
(6) Switch the unit off and remove
the battery.
If it doesn’t work as expected, carefully inspect the solder joints under
magnification. Also check that the
components are all in their correct
positions and that the polarised parts
(diodes, ICs, electrolytic capacitors
etc) are orientated correctly.
Case preparation
If fitting the PCB into a UB3 jiffy box,
you will need to drill four holes in the
side of the case for the microphone
input and headphone output sockets,
plus the gain and volume adjustment
knobs. The bottom section of Fig.3
shows the relevant drilling template
– this can be copied (or downloaded
from the SILICON CHIP website and
printed out) and temporarily stuck to
the side of the case (eg, using doublesided tape).
Note that the top edge of the template must be aligned with the top edge
of the box and centred horizontally.
The holes must be accurately placed.
siliconchip.com.au
If you want to be able to run the
unit from a plugpack, you will
also need to drill a 5.5mm hole in
the other side, to allow access to
the connector. The same template
can be used; simply drill the hole
for the power jack centred on the
same location as that used for the
volume control pot on the opposite
side. If in doubt, check the location
of the power socket on the board
before drilling.
Fitting the microphone
Above: the PCB is a snapfit inside the
case, while the battery sits on a piece
of non-conductive foam (see text).
Start by drilling pilot holes (eg, 3mm)
in each location and then enlarge them
using larger drill bits, a stepped drill bit
or a tapered reamer. Clean up any burrs,
then remove the nuts from the two jack
connectors, screw the nuts and washers all the way onto the potentiometers
and check that the connectors and pots
fit through the holes.
A hole also has to drilled in the
lefthand end of the case for the electret microphone. The hole should
be positioned about 16mm down
from the top of the case and centred
horizontally. Start by drilling a small
pilot hole, then carefully ream the hole
out until the microphone is a tight fit.
Once the mic fits, adjust it so that
its face is flush with the outside of
the case. It can then be secured inside the case using a small amount of
neutral-cure silicone adhesive and the
assembly placed aside to cure while
the case lid is drilled.
Front panel drilling
Three holes are required in the case
lid, for the two LEDs and switch S1.
The drilling template is at the top of
Fig.3 and it’s just a matter of drilling
the holes to size and checking that the
LEDs and switch shaft fit.
Parts List
1 double-sided PCB, coded
04104151, 104 x 60.5mm
1 UB3 jiffy box (optional)
1 10kΩ 9mm single-gang potentiometer (VR2)
1 1kΩ 9mm single-gang potentiometer (VR3)
1 28-pin narrow DIL IC socket
1 14-pin DIL IC socket (optional)
1 8-pin DIL IC socket (optional)
1 piece non-conductive foam, approximately 65 x 40 x 8mm
1 PCB-mount DC socket (CON1)
2 3.5mm switched jack sockets
(CON4,CON5)
1 2-pole 6-position rotary switch
(S1)
1 medium-sized knob, to suit S1
2 small knobs, to suit VR2 & VR3
1 9V battery snap (BAT1)
1 9V alkaline battery (BAT1)
1 pair headphones or earphones
siliconchip.com.au
1 5-pin header, 2.54mm pitch
(CON3) (optional – see text)
1 PCB-mount electret microphone
insert (Jaycar AM4011)
1 3-pin polarised header, 2.54mm
pitch (CON6)
1 3-way polarised header plug
1 70mm-length light duty figure-8
cable
1 10mm length 3mm-diameter
heatshrink
Semiconductors
1 PIC32MX170F256B-I/SP 32-bit
microcontroller programmed with
0420415A.HEX (IC1)
1 TL074 quad JFET-input op amp
(IC2)
1 TDA1543 oversampling DAC (IC3)
1 78L05 5V regulator (REG1)
1 MCP1700-3.3/TO 250mA 3.3V
LDO regulator (REG2)
The next step is to make and attach
the panel label (Fig.4). This can be copied or downloaded and printed onto
photo paper and affixed to the panel
using silicone adhesive. Alternatively
it can be printed onto Datapol/Dataflex
label paper and stuck onto the lid. The
three holes are then cut out using a
sharp hobby knife.
Final assembly
Assuming that the silicone around
the microphone has cured, the PCB
can now be installed in the case. It’s
just a matter of angling the front of the
board down so that the sockets and pot
shafts go into their respective holes,
then pushing down on the back of the
board until it snaps into the integral
side-rails. If it won’t go in, you may
need to enlarge the holes slightly.
Now trial fit the lid. If the LED
heights are wrong, you will need to remove the PCB and adjust them accordingly. Once they fit properly, re-solder
their leads and re-install the board in
the case. The potentiometer nuts can
then be wound forwards until they’re
against the inside face of the case.
Next, rotate S1 to off (fully anticlockwise), then connect the battery
and place it on top of the PCB with a
piece of non-conductive foam sandwiched in between. This will prevent
shorts and also stop the battery from
rattling around inside the case.
Finally, screw the lid in place, then
1 red 3mm LED (LED1)
1 yellow/orange 3mm LED (LED2)
1 1N4004 1A diode (D1)
1 1N5819 1A Schottky diode (D2)
Capacitors
1 220µF 25V electrolytic
3 100µF 16V electrolytic
1 10µF 6V tantalum or SMD ceramic (1210/1206/0805)
2 1µF 50V multi-layer ceramic
3 470nF 63V/100V MKT
5 100nF 50V multi-layer ceramic
1 4.7nF 63V/100V MKT
1 22pF disc ceramic
Resistors (0.25W, 1%)
2 2.2MΩ
2 6.8kΩ
1 1MΩ
1 6.2kΩ
1 100kΩ
1 1kΩ
1 47kΩ
1 680Ω
1 33kΩ
2 470Ω
4 22kΩ
1 22Ω
1 10kΩ
1 10Ω
June 2015 43
Scope3: amplitude modulation-only mode. The output
frequency is fixed at around 185Hz and only its amplitude
varies, increasing for either polarity of infrasound pressure
wave excursion. Each waveform shown here is at maximum
sensitivity and this is how the unit should be used unless it
is overloading due to intense infrasound.
attach the knobs for S1, VR2 & VR3
(the jack socket nuts aren’t required).
Using it
Typically, you would use the device
with the gain somewhere near maximum and the volume adjusted to a
level which is not excessive for the
headphones or earphones being used.
Due to the way the volume control
works, this is likely to be somewhere
near maximum too, although lower
settings may be necessary for “in-ear”
ear-phones.
Sealed headphones or in-ear phones
have the advantage that you can more
easily determine the level of infrasound emitted from sources which
also produce audible frequencies.
Scope4: frequency modulation mode. The signal amplitude
is constant and high (generally the output volume should
be turned down in this mode) and only the frequency
changes in response to infrasonic waves picked up by the
microphone. As before, the frequency increases for one
polarity of wave and decreases for the other.
That’s because they will do a better job
of blocking those audible frequencies
out and allow you to more clearly hear
the output of the device.
An example of this would be a door
slamming shut. This can generate quite
a significant infrasonic pulse but it
may be difficult to hear the unit’s response against the audible noise of the
door slamming. Other sources which
can be used to test the unit include
large air-conditioning units, passing
trucks and large idling engines.
When using one of the frequency
modulation (FM) modes, it is possible to determine the polarity of an
infrasonic pulse. One polarity will
produce a sound which increases in
frequency while the other will produce
a sound that decreases in frequency.
Regular pulses from the same source
will normally have a consistent polarity. Typically, a compression wave will
precede an expansion wave.
Finally, note that a wind shield
may be necessary for the microphone
if the unit is used outdoors. As with
the March 2013 Infrasound Detector,
the windshield from a dynamic microphone could be used.
Alternatively, a separate external
electret microphone (plugged into
CON4) could be used instead of the
inbuilt electret. Just make sure is has
the required high sensitivity, a good
low-frequency response and is able to
operate from the ~0.5mA bias current
SC
supplied by the unit.
Are Your S ILICON C HIP Issues
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available with these handy binders
Order now from www.siliconchip.com.au/Shop/4 or call (02)
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for overseas prices.
44 Silicon Chip
siliconchip.com.au
End of Financial Year
CLEARANCE
OVER 200 DEALS - GET IN QUICK BEFORE WE RUN OUT!
Lead Free Solder
Paste for SMD
NEW
NS-3048
A quick and easy soldering
solution for your surface mount
work and rework. The superior
wetting ability of this lead-free
solder paste results in bright,
smooth and shiny solder joints
with lead free alloys. Easy
application. 10g syringe.
1295
$
Gas Leakage
Detector
PT-4436
ea
1295
$
4-Way 15A
Anderson Connectors
$
NEW
Satellite Finder
WITH LED DISPLAY
4-WAY 15A PT-4434 $12.95
4-WAY 15A WITH LATCH PT-4436 $12.95
$
2 Port Panel
Mount USB Charger MP-3618
This twin USB charger socket is designed to be
professionally panel mounted for automotive
and marine applications. Comes complete with a
protective cap with short-circuit protection.
• Input: 12-24VDC
• Dual USB outputs: 5VDC, 3.1A
• 43(L) x 40(D) x 24(W)mm
$
NEW
2495
$
1295
SAVE $12
LS-3302 WAS $24.95
Align your satellite dish quickly and accurately in
the right direction with this handheld satellite finder.
Perfect for setting up permanent dishes as well as
portable systems on caravans or RVs.
Housed in high impact and corrosion-resistant
shell, these multi-connectors allow easy
connection and disconnection of electrical
equipment. Also available with latch for use in
applications where shock or vibration may be
severe.
NEW
5995
2995
SAVE $10
$
SAVE $40
$
6495
SAVE $15
$
79
SAVE $20
4995
Stereo Audio/Video
RF Modulator LM-3880
Camera Detector
This clever device lets you view DVDs,
video games, and home videos on a TV
via the antenna input of the TV. Easy to
connect and operate, and is supplied with
a 9VDC mains adaptor and 1m female-tomale RF cable.
• Input: RCA White/Red/Yellow
• Outputs: VHF: Ch 2-4; UHF: Ch 21-69
QC-3506 WAS $99.95
Detect covert cameras and listening
devices with this handy little unit. It
uses 6 pulsing LEDs to reveal the
location of a camera by illuminating
its lens when you look through the
lens viewer from up to 10m away.
Earphones supplied for discrete use.
2-In-1 Network
Cable Tester &
Multimeter
XC-5078 WAS $79.95
Autoranging DMM to easily check
cable integrity or measure AC/
DC voltage, etc with just one
device. LAN terminator, loopback
cable and DMM leads included.
Cat III 600V, 2000 count
BUNDLE DEAL FOR REWARDS CARD HOLDERS: PCDUINO
REWARDS BUNDLE:
VALUED OVER $230
Start building your projects with the latest edition of pcDuino single board
mini PC. This starter kit includes the pcDuino V3.0 with Wi-Fi and other
essential accessories at a bargain. See website for details.
BUNDLE DEAL INCLUDES:
PCDUINO V3.0 WI-FI XC-4350 $119
2.4GHZ WIRELESS KEYBOARD & MOUSE XC-5174 $29.95
USB 2.0 REVERSIBLE 4-PORT HUB XC-4304 $19.95
16GB CLASS-10 MICROSD CARD & ADAPTOR XC-4989 $29.95
MAINS ADAPTOR WITH 2XUSB FOR PCDUINO MS-4085 $24.95
HDMI 1.4 LEAD 1.5M WV-7914 $9.95
NOW OPEN: MONA VALE
Catalogue Sale 24 May - 23 June, 2015
QP-2299 WAS $39.95
Gas leaks can be
incredibly dangerous.
This unit detects butane,
propane, acetylene and
methane (natural gas)
gases in seconds.
• Visual & audible
warning
REWARDS CARD OFFER
BUNDLE DEAL!
$
199
SAVE OVER $30
48 DARLEY STREET
MONA VALE NSW 2103 PH: (02) 9979 1711
To order phone 1800 022 888 or visit www.jaycar.com.au
Pro Gas Soldering Kit
TS-1114 WAS $99
Value for money kit with refillable
gas soldering iron, side cutters,
wire stripper/crimper and more.
See online for full contents.
VDE APPROVED INSULATED TOOLS
REWARDS CARD OFFER: 20% OFF THESE SELECTED TOOLS
20% off the prices listed below with Rewards Card.
Jaycar’s range of VDE tools are manufactured from high quality tool steel to meet the highest standard for electrical
safety and mechanical strength suitable for all electrical works. They are TUV and GS approved and rated up to
1000V. Extremely strong and durable, these insulated tools come with ergonomic handles with soft rubber coating
for a secure and comfortable grip. Wide range and sizes available for any application.
TH-1985
TD-2330
SLOTTED SCREWDRIVERS:
2.5MM TIP, 75MM LONG TD-2230 $5.50
3.0MM TIP, 100MM LONG TD-2231 $5.95
5.5MM TIP, 125MM LONG TD-2232 $6.95
6.5MM TIP, 150MM LONG TD-2233 $7.95
8.0MM TIP, 175MM LONG TD-2234 $9.95
FROM
5
$ 50
TD-2235
PHILLIPS SCREWDRIVERS:
SIZE 0, 60MM LONG TD-2235 $5.95
SIZE 1, 80MM LONG TD-2236 $6.50
SIZE 2, 100MM LONG TD-2237 $6.95
SPECIALTY PLIERS
5
CUTTERS AND PLIERS:
TH-1985 $19.95
6.0” SIDE CUTTERS
6.5” LONG NOSE PLIERS TH-1986 $19.95
7.0” BULL NOSE PLIERS TH-1984 $22.95
$
FROM
1995
MASSIVE SAVINGS! UP TO 50% OFF THESE TRADIES TOOLS
$
Screw Removing
Pliers TH-2330 WAS $24.95
FROM
$ 95
TH-1800
17
95
FROM
6
$ 95
SAVE $7
SAVE UP TO $15
Specially designed to remove, by brute force, any
small non-countersunk screw with a hopelessly
stripped out head. Beautifully made and finished.
175mm long. Suits screws from 2 to 5mm.
$
F Connector Seating Tools
Strong, heavy duty F-type tools to help you
in TV or RF distribution systems installation.
Suits RG6 and RG59 cables.
17
95
SAVE $7
Heavy Duty Metal
Bending Pliers TH-2336 WAS $24.95
3-WAY SEATING TOOL TH-1883
WAS $11.95 NOW $6.95 SAVE $5
COMPRESSION CRIMP TOOL TH-1800
WAS $24.95 NOW $14.95 SAVE $10
RATCHET CRIMP TOOL TH-1831
NOW
14
$
95
SAVE $5
Easy Coax Cable Stripper
TH-1813 WAS $19.95
Quickly and easily strip coax cable. Also include
a F-type spanner to tighten your connections.
150mm long.
WAS $39.95 NOW $24.95 SAVE $15
$
NOW
2495
SAVE $15
Ratchet Crimping Tool for
BNC/TNC Connectors
TH-1846 WAS $39.95
A heavy duty tool for crimping BNC/TNC
connectors onto RG58/59/62 coax cable. The tool
features a secure ratchet mechanism for accurate
and reliable crimps.
Easily bend metal sheets with this heavy duty offset
hand tool. Features strengthened rivets and dual
layered pitted handle for a firm grip. 210mm long.
• Jaw width/depth: 75mm/30mm
TH-2334
$
Strong Long
Nose Pliers
FROM
NOW
1995
7
SAVE $10
125MM LONG TH-1885
WAS $34.95 NOW $24.95 SAVE $10
NOW
1195
$
SAVE $8
SAVE $5
SAVE $8
These hook tools have stainless steel heat
treated points. Ideal for use on O-rings,
springs, snap rings, washers, checking
soldering joints, etc.
• Includes 90°, full & small angle hooks
and a straight pick
110MM LONG TH-2334
WAS $29.95 NOW $19.95 SAVE $10
9
$ 95
4-Piece Mini Pick &
Hook Set TH-1762 WAS $15.95
Made from high grade carbon steel. Sturdy box
joint construction and the insulated soft grip
handles are spring loaded for effortless use.
NOW
$ 95
Economy Nibbling Tool
TH-1768 WAS $14.95
Will cut any shape out of aluminium, plastic, copper
and other unhardened metals up to 18 gauge.
Designed to fit in the palm of your hand for easy
use, simply drill a 1/4” hole to start.
6.5” Cable Cutter
TH-1898 WAS $19.95
Stainless steel with a hardened long-life cutting
edge and suitable for cutting cables up to 10mm
diameter. Lightweight and lockable.
BIG SAVINGS, GREAT ADDITIONS FOR YOUR TOOL BOX
NOW
NOW
8
9
1195
$ 95
$ 95
$
SAVE $5
SAVE $6
SAVE $5
4-Piece Countersink Set
TD-2027 WAS $13.95
Easily remove nasty burrs on drilled holes or
countersink them as required. Includes 12, 16, &
19mm bits - all hardened high carbon steel.
Page 2
$
NOW
Versatile File Saw
TH-2127 WAS $15.95
Perfect for cutting odd shaped holes in plastic
pipes, plywood or other soft materials. 175mm
long blade.
Spiral Drive Drill/Driver
TD-2089 WAS $16.95
Ideal for very fine work. Push the handle to rotate
the collet slowly. Add drill bit or screwdriver bit as
required. Includes 2 pin vice collects and 3 small
drill bits. 180mm long.
Follow us at facebook.com/jaycarelectronics
NOW
2995
SAVE $10
LED Magnifying Glass
EXTREMELY STRONG QM-3534 WAS $39.95
Not the kind of magnifier you keep in the desk. All
metal construction and high quality glass lens makes
it ideal for the lab or workshop. Two AA batteries
required.
• 3.5x dioptre, 85mm(Dia) lens
• 2 brightness setting
Catalogue Sale 24 May - 23 June, 2015
GREAT DEALS FOR OUR TOP QUALITY SOLDERING STATIONS
60W ESD Safe Soldering
and Rework Station TS-1574
70W ESD Safe
Soldering Station TS-1440
Precision, high grade instrument with
excellent temperature stability and
anti-static characteristics. Features
precise digital temperature adjustment
and a lightweight soldering pencil.
• Temperature 200°C to 480°C
• 146(L) x 115(W) x 98(H)mm
$
ALSO AVAILABLE:
REPLACEMENT SPONGE TS-1445 $7.95
0.5MM CONICAL TIP
TS-1441 $19.95
0.2MM CONICAL TIP
TS-1442 $19.95
299
REWARDS CARD OFFER: FREE 2
SPARE TIPS* TS-1441 or TS-1442
2 free tips of your choice. Valid with purchase of TS-1440.
*
VALUED AT $19.95 EA.
Complete solder/desolder station for production
and service use. Soldering/rework functions can
be operated independently of each
other. Suitable for lead-free solder.
• Microprocessor controlled
• Temperature 160°C to 480°C
• Celsius and Fahrenheit display
• 225(L) x 215(W) x155(H)mm
SPARE TIPS:
2.5MM SINGLE TIP
4.4MM SINGLE TIP
10X10MM QUAD TIP
15X15MM QUAD TIP
$
299
REWARDS CARD OFFER:
FREE 2 SPARE TIPS*
TS-1575, TS-1576, TS-1577 or TS-1578
TS-1575 $13.95
2 free tips of your choice. Valid with purchase of TS-1574.
TS-1576 $13.95
*
TS-1577 $19.95
TS-1575 & TS-1576 VALUED AT $13.95 EA.
TS-1577 & TS-1578 VALUED AT $19.95 EA.
TS-1578 $19.95
GREAT SAVINGS FOR YOUR WORK SPACE!
BARGAIN DEALS
FREE SOLDER REEL DISPENSER FOR
REWARDS CARD HOLDERS* TS-1504
Valid with purchase of NS-3002 or NS-3015
*
NOW
179
$
$
SAVE $50
NOW
299
$
SAVE $70
Variable Laboratory
Autotransformer (Variac)
MP-3080 WAS $229
Encased in heavy-duty steel housing, this unit
enables the AC input to a mains powered appliance
to be easily varied from 0 to full line voltage.
• Rated power handling: 500VA (fused)
• Output Voltage: 0 to 260VAC <at>50Hz
• 165(D) x 120(W) x 160(H)mm
High-Powered Switchmode
Power Supply
MP-3090 WAS $369
A tough no-nonsense power supply that is ideal for
high current and car audio applications. Overload
protected with a max output 40A.
• Variable output voltage: 3VDC to 15VDC
• Fixed voltage mode: 13.8VDC
• 220(W) x 110(H) x 300(L)mm
TS-1504 VALUED
AT $17.95
NOW
299
SAVE $80
Dual Output
Laboratory Power Supply
MP-3087 WAS $379
Dual 0 to 32VDC 3A power supplies in one case.
The two outputs can be operated independently,
connected in parallel, or series for multiple output
currents and voltages. Large backlit display.
• Output voltage: 0-32VDC (x2)
• Output current: 0-3A (x2)
• 185(H) x 260(W) x 400(D)mm
$
7495
ea
Lead-Free Solders
1kg Rolls
99.3% tin, 0.7% copper lead free.
Two sizes to suit every application.
0.71MM NS-3002 $74.95
1.00MM NS-3015 $74.95
REWARDS CARD OFFER
NOW
139
$
Digital
Bench Scale
NOW
129
$
SAVE $30
QM-7264 WAS $159
Precision 1kg electronic scale with 0.01g
resolution. Weighs in grams, ounces, pounds,
grains, carats and troy ounces. Powered by mains
or batteries (not included).
• Automatic calibration
• Tare and counting function
• 175(W) x 75(H) x 260(D)mm
SAVE $30
2.5L 170W
Digital Ultrasonic Cleaner
YH-5412 WAS $169
Professional quality machine for quick and
convenient cleaning of industrial parts, electronic
equipment and more. Features large 2.5L stainless
steel bowl and controllable heating element.
• 5 selectable time settings
• 290(W) x 223(D) x 185(H)mm
$
BUY ALL 3 FOR
FROM
449
SAVE UP TO $100
$
QC-1932
Dual Channel Digital
Storage Oscilloscopes
59
SAVE OVER $20
REWARDS BUNDLE:
Anti-static Products
VALUED AT $79.85
Designed for technicians, electronic enthusiasts
and professional engineers. Features trace
capture, PC interface, storage of data on
portable media etc.
CONDUCTIVE BRUSH TH-1775 $9.95
WORK MAT 555(W) x 290(D)mm TH-1783
25MHZ, 500MSA/S 5.7” Screen. QC-1932
WAS $499 NOW $449 SAVE $50
$19.95
100MHZ, 1GSA/S 7” Screen. QC-1934
WAS $899 NOW $799 SAVE $100
FIELD SERVICE MAT KIT TH-1776 $49.95
TOP QUALITY WORKBENCH TOOLS
FROM
9
$ 95
SAVE UP TO $7
Step Drill Bits
Drill multiple size holes with the one bit! Ideal for
plastics, aluminium or copper sheeting up to 4mm
thick. Made from high speed steel. 1mm steps.
4-12MM TD-2436
WAS $14.95 NOW $9.95 SAVE $5
12-20MM TD-2438
WAS $24.95 NOW $17.95 SAVE $7
NOW
9
$ 95
SAVE $5
Mini Bench Vice
TH-1764 WAS $14.95
This strong, lightweight aluminium vice will clamp
to surfaces up to 25mm thick and hold material up
to 50mm thick. Great for repairs on the go.
ALSO AVAILABLE:
270° CLAMP VICE TH-1769
WAS $24.95 NOW $19.95 SAVE $5
To order phone 1800 022 888 or visit www.jaycar.com.au
$
NOW
3995
SAVE $10
Sheet Metal Bender
TH-1763 WAS $49.95
This unit sits in the jaws of your bench vice
(100mm+ recommended) and it retains
itself in the vice with strong recessed
magnets. Folds sheet up to 125 wide and
bend steel strips up to 4mm thick and
25mm wide.
See terms & conditions on page 8.
IF YOU’RE A PROFESSIONAL AND REGULARLY
PURCHASE ELECTRONICS GOODS FOR
BUSINESS PURPOSES, YOU MAY BE ELIGIBLE
FOR SPECIAL TRADE PRICES AT JAYCAR
COMPANY STORES* ON SELECTED ITEMS.
Conditions apply. See website for T&Cs
*
VISIT YOUR LOCAL JAYCAR STORE
TODAY & FIND OUT HOW.
Page 3
IP67 RATED TRUE RMS DIGITAL MULTIMETERS
GREAT DEALS FOR REWARDS CARD HOLDERS
Our range of high quality true RMS digital multimeter (DMM) provides the durability, accuracy and
performance needed for the professional user. All DMMs are packed with multi functions to suit a wide range
of electrical work, including AC Voltage, DC Voltage, AC Current, DC Current, Resistance, Capacitance,
Frequency, Temperature (except QM-1549), Continuity and Diode Test.
• Auto-ranging, data hold, relative measurement
QM-1549
QM-1571
QM-1543
QM-1576
Special Features
Value-for-money CAT
IV DMM for most
electrical works
Wireless USB
interface and logging
software for computer
based analysis
Drop proof to 2m.
Includes bargraph
and K-type
thermocouple.
View live data,
diagnose, email &
share your results to
the Cloud - all from
your Smartphone!
Display (Count)
4,000
4,000
40,000
40,000
Security
Cat IV 600V
Volts DC/AC
1,000V
Amp DC/AC
10A
Resistance
40M
Frequency
10MHz
REWARDS
CARD
$
Capacitance
100μF
100μF
40mF
40mF
RRP
$79.95
$109
$159
$229
MULTI-FUNCTIONAL DMM
8495
79
SPECIAL
$
129
QM-1576
SAVE $15
SAVE $30
SAVE $30
SAVE $40
QM-1020
Still the best way to test a capacitor.
This well-made analogue meter has
audible continuity and a transistor
test, in addition to the normal set
of functions.
• AC/DC voltages up to 1000V
• DC current up to 250mA
• Resistance measurement
IDEAL FOR TRADIES.
ONLY 16MM THICK!
$
2495
Inductance / Capacitance
Digital Multimeter
SAVE $20
DOUBLE
POINTS
Pocket-Sized Digital
Multimeter
QM-1328
A handy pocket-sized multimeter
with plenty of features. Large LCD
display with autoranging, data hold
and relative functions.
• Cat III 600V, 4000 count
• AC/DC voltages up to 600V
• 115(H) x 60(W) x 16(D)mm
DOUBLE
POINTS
189
189
QM-1543
*Valid for purchase of QM-1020, QM-1328, QM-1548, or QM-1551.
Insulation Meter
$
SPECIAL
$
QM-1571
Analogue Multimeter
$
SPECIAL
$
REWARDS
CARD
QM-1549
DOUBLE
POINTS
SAVE $15
QM-1493 WAS $209
Suitable for high voltage insulation
testing up to 4 gigaohms at up to
1000V in electrical and electronic
testing applications.
• Cat III 1000V, 4000 count
• Test Voltage & Current: 125V,
250V, 500V, 1000V <at>1mA
nominal
• Bargraph, test hold & lock
64
95
REWARDS
CARD
DOUBLE POINTS FOR REWARDS CARD HOLDERS ON THESE MULTIMETERS*
Environment Meter
QM-1594 WAS $99.95
Combines the functions of a sound
level meter, light meter, humidity
meter and temperature meter to help
get the job done faster.
• Cat III 300V, 4000 count
• AC/DC voltages up to 250V
• AC/DC current up to 10A
• Resistance, non-contact
voltage measurement
SPECIAL
REWARDS
CARD
QM-1548
Ideal for audio enthusiasts designing
their own crossovers.
• Cat III 600V, 2000 count
• AC/DC voltages up to 1000V/750V
• AC/DC current up to 10A
$
• Hfe & temperature tests
4995
$
2995
DOUBLE
POINTS
Best Value True RMS
Digital Multimeter
QM-1551
A powerful autoranging multimeter that
includes non-contact voltage testing
and measures temperature, resistance,
capacitance and more.
• Cat III 600V, 4000 count
• AC/DC voltages up to 600V
$
• AC/DC current up to 10A
5995
REWARDS CARD OFFER: UP TO 35% OFF THESE NON-CONTACT THERMOMETERS*
*Valid for purchase of QM-7218, QM-1602, or QM-1601.
EARN A POINT FOR EVERY DOLLAR
SPENT AT ANY JAYCAR COMPANY
STORE* & BE REWARDED WITH A $25
REWARDS CASH CARD ONCE YOU
REACH 500 POINTS! *
Conditions apply. See website for T&Cs.
REGISTER ONLINE TODAY BY VISITING:
www.jaycar.com.au/rewards
Page 4
REWARDS CARD
SPECIAL
Mini IP67 Infrared $1995
SAVE $10
Thermometer
QM-7218 $29.95
Ultra compact, non-contact thermometer with
LCD readout in Celsius or Fahrenheit. 1:1
distance to spot ratio.
• -33 to +110ºC (±2.5%)
• 82(L) x 17(Dia)mm
Thermocouple
Thermometer
Pocket-Sized
Thermocouple
Thermometer
QM-1602 $39.95
Highly accurate and wide range
with k-type thermocouple
suitable for the lab, workshop
or in the field. 2000 count.
• Thermocouples included
• -50 to +750ºC (±1%)
• 118(L) x 70(W) x 29(D)mm
Follow us at twitter.com/jaycarAU
REWARDS CARD
SPECIAL
$
2495
SAVE $15
QM-1601 $79.95
Fast response and laboratory
accuracy, works with K-type
thermocouples and offers 0.1 or
1° user-selectable resolution in
Celsius or Fahrenheit. Monitor
two separate temperatures or
use the differential function to
compare them. 2000 count.
• Thermocouples included
• -50 to +1300°C (±0.5%)
• 172(H) x 84(W) x 42(D)mm
REWARDS CARD
SPECIAL
$
5995
SAVE $20
Catalogue Sale 24 May - 23 June, 2015
SMART DATA TOOLS
FOR ON-SITE TESTING & DIAGNOSIS
NOW
119
$
SAVE $30
USB Temperature /
Humidity Datalogger
QP-6014 WAS $149
Logs temperature and humidity
readings and store them in internal
memory for later download to a PC.
• 32,000+ memory samples
• Temp -40 to +70°C (±1°C)
• Humidity 0 to 100% (±3°C)
• Windows 2000/XP/Vista compatible
NOW
169
$
$
SAVE $30
NOW
219
$
SAVE $30
Handheld
Function Generator
QT-2304 WAS $199
A bench top generator in a portable size. Produces
sine, square, and triangle waveform signals with
output frequency adjustment from 1Hz to 1MHz with
maximum amplitude of 8Vpp.
• Sweep modes: Linear/logarithmic, single/
bidirectional
SAVE $50
Handheld
Pocket Scope
QC-1914 WAS $249
A complete portable oscilloscope in a tiny size.
Aside from standard scope features, it has nifty
tools for measurement of RMS speaker power,
display hold function, and memory storage for 2
signals. Includes CRO probe and USB charge cable.
• Real Time Sample Rate: 40MSa/s
• Input 1mV to 20V per division in 14 steps
2-In-1 Handheld
Scope & Multimeter
QM-1577 WAS $399
Combines all functions of a 4,000 count True RMS
CAT III digital multimeter and a 10MHz oscilloscope.
One-keypress switches between DMM and DSO.
Includes USB interface and PC logging software.
• 128 x 128 graphic LCD display
• Autoranging, AC/DC voltage (1000V), current (20A)
• 50MSa/s sample rate
PROFESSIONAL ENVIRONMENT METERS
IDEAL FOR CHECKING
BUILDINGS AFTER
ALL THE RAIN
$
49
SAVE $5
Handheld
pH Meter
Pocket
Moisture Meter
$
95
SAVE $15
2495
SAVE, SAVE, SAVE!
NOW
NOW
$
NOW
$
99
SAVE $30
Professional
Light Meter
QM-1584 WAS $129
Extremely accurate with a rapid response and can
store min and max values for easy comparisons.
Measurement can be switched between Lux and FC
(foot candles).
• Max 400k lux
• Separate photo detector
ALSO AVAILABLE:
REPLACEMENT SOLUTION 50ML
QM-1622 WAS $139
This highly accurate unit allows
you to easily measure the
distance between two points
beyond the common tape
measure. It also allows you to
automatically calculate area,
volume or height.
• Measurement 0.05 to 35m
(±1.5mm)
• Stores up to 20
measurements
SAVE $20
Capture videos and images in areas where your
head or hands simply can’t fit into. Ideal for
seeing inside car engine bays, checking inside
pipes, under grates, in ceilings, and more.
• 640x480 resolution
• Camera: 10mm (Dia)
Network Cable Tracer
XC-5083 WAS $99.95
Easily trace cables even when cables are in a bundle
or hidden in punchdown blocks or wall plates. Also
checks telephone line polarity and status
ie. ring/busy/idle.
• Single/multi tone signal
1.5M FLEXIBLE CABLE QC-3373
WAS $44.95 NOW $34.95 SAVE $10
7.0M FLEXIBLE CABLE QC-3374
WAS $64.95 NOW $49.95
SAVE $15
3-In-1 Stud
Detector
Professional
Sound Level
Meter WAS $399
NOW
109
$
3495
USB Mini
Inspection Cameras
QM-1671 WAS $8.95 NOW $3.95 SAVE $5
Professional Laser
Distance Meter
FROM
SAVE UP TO $15
NOW
7995
$
QM-1670 WAS $64.95
An accurate device for checking pH levels in water.
Includes 9V battery, pH 7.0 buffer solution and
QP-2310 WAS $29.95
calibration tool. Replacement pH solution available
An intelligent meter with 8mm electrode suitable for
separately.
measuring water content in building materials and
• Range 1-14 pH (±0.2 pH)
wooden fibre articles.
• Resolution: 0.1 pH
• 6 to 44% (Wood) / 0.2 to 2.0% (Material)
• 96(H) x 40(W) x 20(D)mm
• 4 x LR44 batteries included
NOW
349
WITH LASER LEVEL
QM-1592
Scales for A and C weighting
are included so it’s ideal for
vehicle noise testing, traffic
noise or any evidence-based
noise testing.
• 30 to 130dB (±1.4dB)
NOW
• IEC 61672-1 Class 2
$
compliant
329
SAVE $30
SAVE $70
QP-2288 WAS $59.95
Indicates proximity when you
are near a stud via its large
LCD and shows a target
graphic when you’re spot on.
Built-in voltage detection.
• Detects wood, metal and
live wire
• Thumb dial adjustable
feet for levelling the laser
$
4495
SAVE $15
REWARDS CARD OFFER: UP TO 35% OFF THESE AUTO TESTERS*
*Valid for purchase of QP-2258, QP-2212, QM-1494, or QM-1448.
RUGGED METAL
BODY!
REWARDS CARD
REWARDS CARD
SPECIAL
SPECIAL
9
$ 95
REWARDS CARD
SPECIAL
7
SAVE $6
$ 95
SAVE $5
3-In-1 Auto Tester
QP-2258 $12.95
Quickly check the condition of your 12V
battery, charger or alternator. Compact &
lightweight. 12VDC.
Cordless Voltage Tester
QP-2212 $15.95
Quick and easy way to locate electrical faults
without a bulky meter or ground wire. Works on
3-28V circuits. It lights up and buzz when positive
voltage is detected. Probe is supplied with a
V-Groove tip to make piercing wire insulation safe.
To order phone 1800 022 888 or visit www.jaycar.com.au
$
44
95
SAVE $15
Multi-Function Circuit Tester
QM-1494 $59.95
Designed for 12/24V vehicles, it tests polarity,
voltage, short/open status, lights and more.
Quickly test circuits without using jumper wires.
All the features of a brand name unit at a fraction
of the price.
See terms & conditions on page 8.
REWARDS CARD
SPECIAL
$
5995
SAVE $20
Digital
Tachometer
QM-1448 $79.95
Measures up to 99,999RPM and can also count
revolutions. Large LCD screen, laser pointer and
min/max recall. 5 digits display.
Four AA batteries included.
Page 5
UP TO 70% OFF CLEARANCE STOCK
TEST & TOOLS
See website for technical specifications
PCB Holder
Repair
Kit for
iPhone®
WITH 90MM
MAGNIFYING
GLASS
Network
Cable Tester
- UTP/STP/
Coax/Mod
19 PIECE
TH-1983
ORRP $12.95
TD-2113
ORRP $29.95
NOW
9
SAVE $3
$
PCB not included
Forehead & Ear
Thermometer
NOW
QM-7271 ORRP $29.95
$
SAVE $10
NOW
2295
SAVE UP TO 70%
SF-5122
RQ-5289
RQ-5298
RQ-5285
PS-0532
PP-1154
PP-1148
PP-1128
PA-3692
PA-3690
HC-4066
HC-4062
PP-0209
PS-0280
HH-8607
HP-1156
ZV-1637
ZZ-8800
PI-6483
HOT!
HOT!
HOT!
Blade Fuse Mini Wire Tap 15A
Crystal 10MHz HC49U
Crystal 38kHz DT38 Miniature
Crystal 6MHz HC49U
DC Socket 0.7mm PCB Mnt with Slide Switch
IDC Locking Right-Angle Header 16 Pin
IDC Locking Vertical Header 50 Pin
IDC Right-Angle Header 34 Pin
Plug 1.75mm to Suit Plugpack - Green Dot
Plug 1.7mm to Suit Plugpack - Blue Dot
Power Terminal Gold Plated 2GA
Power Terminal Gold Plated 4GA
RCA Plug Crimpless - Green
RCA Socket Double - PCB Mount
TO-220 Dual Heatsink Clamp Pk 100
TO-220 Rubber ORRPher Pk100
Voltage Regulator LM2678T-12
Wafer Card with PIC16F84A + 24LC16B
ZIF Socket 28 Pin
HOT!
HOT!
HOT!
HOT!
HOT!
ORRP
NOW
SAVE
$6.95
$4.50
$4.50
$4.50
$5.95
$1.75
$3.75
$2.25
$2.95
$2.95
$8.95
$8.95
$3.50
$1.95
$19.95
$17.95
$16.95
$11.95
$14.50
$1.95
$1.50
$1.50
$1.50
$2.95
$0.75
$1.95
$0.95
$1.65
$1.65
$4.95
$4.95
$1.50
$0.95
$11.95
$7.95
$8.95
$5.95
$6.50
$5.00
$3.00
$3.00
$3.00
$3.00
$1.00
$1.80
$1.30
$1.30
$1.30
$4.00
$4.00
$2.00
$1.00
$8.00
$10.00
$8.00
$6.00
$8.00
SAVE $8
WITH 200X ZOOM
$
SAVE $12
NOW
2195
USB Digital
Microscope
2MP
QM-7201
ORRP $89.95
1995
$
SAVE $20
WITH SMARTPHONE APP
NOW
CAT. NO. PRODUCT
NOW
1995
Body
Thermometer
QM-7272
ORRP $34.95
$
TD-2107
ORRP $29.95
$
SAVE $12
Ear
Thermometer
30 PIECES
XC-5076
ORRP $39.95
1795
$ 95
Electronic
Tool Kit
NOW
6995
QC-3197
ORRP $79.95
$
SAVE $20
NOW
5495
SAVE $25
HARDCORE COMPONENTS
See website for technical specifications
PLCC Socket
Surface Mount 84 Pin
PI-6630 ORRP $5.95
Power Terminal
Gold Plated 0GA
HC-4068 ORRP $8.95
NOW
95
c
SAVE $5
NOW
3
$ 95
SAVE $5
D-Sub Socket
25-Pin Waterproof
PS-1220 ORRP $19.95
NOW
1295
$
SAVE $7
NOW
ZIF Socket
40 Pin
6
$ 50
PI-6484 ORRP $15.50
SAVE $9
AUTO & OUTDOORS
See website for technical specifications
NOW
9
$ 95
$
SAVE $10
NOW
2495
$
SAVE $10
Car Charger/Audio Kit
iPhone not included.
Car Holder & FM Transmitter
FOR IPHONE®/IPOD® MB-3653 ORRP $19.95 FOR IPHONE®5 AR-3125 ORRP $34.95
Car OBD2 Computer
Memory Saver
Map Measure Digital
WITH LED LIGHT
XC-0374
ORRP $9.95
PP-2140 ORRP $9.95
NOW
4
NOW
6495
SAVE $15
NOW
5
Reversing Camera
12-24VDC Siren
Waterproof
Rechargeable
Camping Shower
NOW
2495
$ 95
$ 95
$
SAVE $5
SAVE $4
SAVE $10
Page 6
SAVE $30
Car Mini Dash
Cam 1080p QV-3846 ORRP $79.95
LA-8903
ORRP $34.95
Follow us at facebook.com/jaycarelectronics
NOW
169
$
WITH 5 INCH LCD MONITOR
QM-3741 ORRP $199
YS-2802
ORRP $39.95
$
NOW
2795
SAVE $12
Catalogue Sale 24 May - 23 June, 2015
UP TO 80% OFF CLEARANCE STOCK
AUDIO & VIDEO
See website for technical specifications
SAVE UP TO 80%
CAT. NO. PRODUCT
WQ-7299
AA-0373
AA-2097
AR-1895
LT-3205
WQ-7298
SL-3441
AS-2084
AA-2069
AA-2079
AM-4087
AX-3598
PT-0475
YN-8059
3.5mm/Toslink Fibre Optic Swappable Lead
Amplifier Module Mono 0.5W
Handsfree Aux Mic Lead For Smartphones
Amplifier Stereo Wireless 2.4GHz 15WRMS
Antenna Mount Adjustable Bracket
Audio Lead Toslink-3.5mm Fibre Optic - 1m
Disco LED RGB Light - Flashing
Earphones for Kids with Volume Limiter
Earphones Stereo/Bluetooth®/Rechargeable
Earphones with TV Hearing Aid
Microphone Desktop 3.5mm Plug
Speaker Protection Grille 15" with Clips
Wallplate Multimedia VGA/HDMI/RCA/3.5mm
Wallplate VGA Socket with 4 Ports
HOT!
HOT!
HOT!
HOT!
HOT!
ORRP
NOW
SAVE
$14.95
$11.95
$9.95
$99.00
$24.95
$9.95
$79.95
$9.95
$74.95
$129.00
$12.95
$12.00
$29.95
$9.95
$6.95
$5.95
$5.95
$49.00
$16.95
$4.95
$59.95
$3.95
$54.95
$79.00
$7.95
$2.00
$19.95
$4.95
$8.00
$6.00
$4
$50.00
$8.00
$5.00
$20.00
$6.00
$20.00
$50.00
$5.00
$10.00
$10.00
$5.00
NOW
7995
$
SAVE $20
NOW
$
99
SAVE $20
Cassette Player
HDMI Switcher 4 Input
GE-4139 ORRP $99.95
AC-1709 ORRP $119
WITH USB/SD ENCODER
$
NOW
4495
SAVE $15
Video Converter DVI to VGA
WQ-7445 ORRP $59.95
WITH AUDIO RETURN
$
NOW
6995
SAVE $30
Speaker Stand
EXTRA HEAVY DUTY
CW-2860 ORRP $99.95
IT & COMMUNICATIONS
See website for technical specifications
SAVE UP TO 60%
CAT. NO. PRODUCT
WC-7729
MB-3695
HS-9016
WC-7717
AR-1889
AR-3320
XC-5202
XC-4949
XC-5412
WC-7510
XC-5220
XC-4691
XC-4143
WC-7736
YN-8364
Adaptor Plug - Micro-B USB to Lightning
Battery Back-up Case to suit iPhone 5®
Bicycle Bracket Mount for iPhone 3/4®
Docking Station for Apple® to HDMI Device
Docking Station/Speaker for iPhone®/iPod®
FME to Telstra 4G USB Modem Cable
Keyboard Foldable with Bluetooth®
KVM & Data Transfer USB Cable
Laser Pointer Plug-in for iPod®/iPhone®
RS232 Extension Computer Lead 3m
Speaker Wireless - Near Field Audio
USB 3.0 Cloud Dock
USB 3.0 Dual Port PCI-E Interface Card
USB Retractable Lead A-Plug to MicroB Skt
Wi-Fi Extender Dual Band
HOT!
HOT!
HOT!
HOT!
HOT!
HOT!
ORRP
NOW
SAVE
$14.95
$39.95
$19.95
$49.95
$49.95
$16.95
$39.95
$49.95
$19.95
$19.95
$39.95
$99.00
$34.95
$11.95
$89.95
$6.95
$29.95
$7.95
$24.95
$24.95
$6.95
$24.95
$34.95
$11.95
$11.95
$24.95
$59.00
$29.95
$6.95
$64.95
$8.00
$10.00
$12.00
$25.00
$25.00
$10.00
$15.00
$15.00
$8.00
$8.00
$15.00
$40.00
$5.00
$5.00
$25.00
$
NOW
27
95
$
SAVE $12
Stereo Car Handsfree Kit
WITH BLUETOOTH® TECHNOLOGY
AR-3130 ORRP $39.95
$
Panel Mount Bluetooth
Receiver WITH MIC
AR-3129 ORRP $49.95
95
$
SAVE $20
Wireless Presenter
WITH MOUSE AND LASER
XC-5413 ORRP $59.95
3495
SAVE $15
NOW
39
NOW
NOW
399
SAVE $50
UPS Online Rack Mountable
1000VA/700W MP-5212 ORRP $449
SECURITY & SURVEILLANCE
See website for technical specifications
SAVE UP TO 70%
CAT. NO. PRODUCT
ORRP
NOW
SAVE
QC-8627
MP-3351
QC-8644
LA-5024
SL-3232
LA-5156
LA-5355
LA-5214
LA-5262
LA-5005
LA-5174
LA-5304
LA-5303
LA-5163
$99.95
$39.95
$149.00
$44.95
$49.95
$299.00
$39.95
$19.95
$44.95
$19.95
$59.95
$24.95
$24.95
$9.95
$69.95
$24.95
$119.00
$29.95
$27.95
$209.00
$29.95
$8.95
$39.95
$4.95
$27.95
$9.95
$9.95
$6.95
$30.00
$15.00
$30.00
$15.00
$22.00
$90.00
$10.00
$11.00
$5.00
$15.00
$32.00
$15.00
$15.00
$3.00
Bullet Camera Weatherproof with IR 600TVL
CCTV Power Distributor Box
Dome Camera CCD 3-Axis with IR 800TVL
Doorbell Wireless with MP3 Music
Emergency Spotlight Rechargeable with PIR
Intelligent GSM Wireless Alarm System
Keypad Security 12VDC
Keypad Shed Alarm
Siren with 10 Sounds and Mic 12V
Solar Powered Magnetic Entry Alarm
Solar Wireless PIR Announcer
Strobe Light Mini - Orange
Strobe Light Mini - Red
Water Leakage Alarm 120dB Siren
HOT!
HOT!
HOT!
HOT!
HOT!
To order phone 1800 022 888 or visit www.jaycar.com.au
NOW
$
99
SAVE $50
Bullet Camera CCD
WITH IR 650TVL QC-8634 ORRP $149
NOW
7995
$
SAVE $20
Wi-Fi IP Camera
Ai-Ball VGA QC-3368 ORRP $99.95
See terms & conditions on page 8.
NOW
$
99
SAVE $50
Dome Camera CCD
WITH IR 650TVL QC-8636 ORRP $149
$
NOW
549
SAVE $150
DVR 16-Channel Network
WITH 1TB HDD QV-3039 ORRP $699
Page 7
UP TO 60% OFF CLEARANCE STOCK
Listed below are a number of discontinued (but still good) items that we can no longer afford to hold stock. Please ring your local store to check stock. At these prices
we won’t be able to transfer from store to store. STOCK IS LIMITED. ACT NOW TO AVOID DISAPPOINTMENT. SORRY NO RAINCHECKS.
POWER & LIGHTING
See website for technical specifications
CAT. NO. PRODUCT
HH-8549
HH-8547
SB-2540
MB-3605
MB-3646
HM-3086
ST-3206
SL-2220
SL-2222
ST-3291
SL-3140
SL-3458
ZD-0373
AA-0595
ST-3085
SL-2210
SL-2216
SL-2231
SL-2207
SL-3472
ZD-0606
ZD-0605
SL-3465
ZD-0463
SL-3139
ST-3341
ST-3357
ST-3486
ST-2807
SL-3473
ST-3264
PP-4039
MS-6158
MP-3452
ST-3460
Aluminium Extrusion 2-Pce for LED Strip 1m
Aluminium Extrusion for LED Strip 1m
Battery Lithium 3.6V for Motherboard
Battery Backup with Lightning® Connector
Battery Bank with iPod® Charger 5000mAh
Battery Clamps Stainless Steel 400A
LED Book/Laptop Reading Light
LED Candle Globe E14 2800K 3.2W 230Lm
LED Candle Globe E14 4000K 3.2W 230Lm
LED Cap Torch 160Lm
LED Desk Lamp with USB Charger
LED Downlight "Hockey Puck" Style 45Lm
LED Downlight Kits 3000K 15W 900Lm
LED Driver Constant Current - Dimmable
LED Emergency Light with Magnetic Base
LED Globe Dimmable/Bayonet 2800K 5W 400Lm
LED Globe Dimmable/Bayonet 4000K 10W 900Lm
LED Globe Dimmable/Screw 2800K 8W 500Lm
LED Globe Dimmable/Screw 6000K 10W 900Lm
LED Spotlight Gymbal Flush Mount 3W 165Lm
LED Spotlight MR16 2800K 4.5W 220Lm
LED Spotlight MR16 6000K 4.5W 250Lm
LED Strip Lamp For Vehicles C. White 140Lm
LED Strip Warm White 500(L)x8(W)mm 12V 150Lm
LED Table Lamp 3500-5500K 270Lm
LED Torch Multi-Functional Dynamo
LED Torch with Radio & Dynamo Charger
LED Torch Yellow 300 Lumens
LED USB Flexible Light 6000K 300Lux
LED Wall/Desk Mount Gooseneck Lamp 75Lm
LED Worklight Low Cost 12V
Mains Double Adaptor with Night Light
Mains Sockets IR Controlled Wireless
Mains Travel USB Adaptor
Torch Magnetic with Gooseneck 150Lm
HOT!
HOT!
HOT!
HOT!
HOT!
HOT!
HOT!
HOT!
ORRP
NOW
SAVE
$29.95
$22.95
$15.95
$34.95
$59.95
$9.95
$19.95
$19.95
$19.95
$12.95
$39.95
$17.95
$99.00
$12.95
$14.95
$14.95
$29.95
$22.95
$29.95
$34.95
$19.95
$19.95
$24.95
$14.95
$89.95
$19.95
$29.95
$19.95
$14.95
$19.95
$29.95
$9.95
$26.95
$12.95
$44.95
$14.95
$10.95
$5.95
$19.95
$39.95
$4.95
$11.95
$11.95
$11.95
$7.95
$29.95
$12.95
$39.00
$9.95
$9.95
$9.95
$17.95
$12.95
$17.95
$24.95
$9.95
$9.95
$19.95
$8.95
$74.95
$11.95
$21.95
$11.95
$9.95
$14.95
$21.95
$4.95
$9.95
$6.95
$21.95
$15.00
$12.00
$10.00
$15.00
$20.00
$5.00
$8.00
$8.00
$8.00
$5.00
$10.00
$5.00
$60.00
$3.00
$5.00
$5.00
$12.00
$10.00
$12.00
$10.00
$10.00
$10.00
$5.00
$6.00
$15.00
$8.00
$8.00
$8.00
$5.00
$5.00
$8.00
$5.00
$17.00
$6.00
$23.00
NOW
6
$
SAVE $8
SAVE $30
Snap-On Battery Terminals
RED / BLACK 500A HM-3087 ORRP $14.95
$
Solar Panel Monocrystalline
12V 90W ZM-9086 ORRP $249
NOW
2495
$
SAVE $15
NOW
2995
SAVE $20
LED Spot / Running Lamps
12V 120Lm SL-3445 ORRP $39.95
LED Worklight 240V
IP65 600Lm ST-3263 ORRP $49.95
NOW
$
NOW
219
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SERVICEMAN'S LOG
Diversifying – it’s not that easy
Diversifying into smartphone and tablet
repairs seemed like a good idea some time
ago but experience has proven otherwise.
And no more was this brought home to me
than a scrape I got myself into with a couple
of smartphones I recently wasted a lot of
time on.
In this business, the name of the
game is diversification. This often
means changing direction and focus
from an existing core business model
to something new (yet hopefully
complementary) in order to increase
custom and income potential.
Indeed, I’ve talked about this before
because on many levels, the computer
repair industry is a dying one. The
golden days enjoyed by the local computer guy have long gone due to a now
much more tech-savvy public and due
to turn-key software and related systems that require no specialist know
ledge to set up, configure or maintain.
Ten years ago, just about every
household boasted a desktop com-
puter that was typically shared by the
whole family. Sometimes there would
be a couple of machines; one for the
kids and one for mum and dad. These
days, however, many households no
longer bother with a desktop computer
because the kids likely have their own
smartphones and/or tablets for doing
school work (and communicating with
each other via social media), while
mum and dad also have smart-phones
and perhaps a work-supplied laptop
or tablet on which to do their Internet
banking, “Skypeing” and emailing.
Now I know I’m being terribly stereotypical but such generalisations
hammer home my point. While in some
instances a laptop, phone or tablet can
Dave Thompson*
Items Covered This Month
• No-name smartphone repair
• Industrial machine servicing
• Modifying & repairing an offgrid battery charger
*Dave Thompson runs PC Anytime
in Christchurch, NZ.
Website: www.pcanytime.co.nz
Email: dave<at>pcanytime.co.nz
never replace a desktop for some tasks
(eg, high-end architectural or graphics
designers), the fact remains that the
number of families owning a communal desktop computer has significantly
declined over the past few years.
These days, when the “family”
desktop starts playing up or reaches its
end-of-life, it’s typically not repaired
or replaced because there is no longer
a need for it. And this scenario is
increasingly being repeated. Understandably, people can’t rationalise
spending even a few hundred dollars
on something they are not going to use
anywhere near as much as they used
to, especially when they have other
gadgets that can do a similar job.
Another nail
Unfortunately, the demise of the
desktop is just another nail in the
coffin for the computer serviceman
because a large portion of our bread
and butter work goes with it. And
while there can be valid arguments
for repairing a laptop, in most cases
they are so cheap to buy and the parts
so ridiculously expensive (or not even
obtainable) that repairing them has
become either uneconomical or simply
not feasible.
The same philosophy applies even
more so to smartphones and tablets,
which leaves retail sales or, at a stretch,
consulting work as the only potential
income streams for micro-businesses
like mine. In the case of sales, however,
we simply cannot compete with the
siliconchip.com.au
June 2015 53
Serviceman’s Log – continued
large retailers and as for consulting
work, anyone can find out pretty much
anything they need to know on Google
these days – all at no cost. So shelling
out even minimum wage money to get
a “specialist” in isn’t warranted.
When I discuss this with other
people, the first thing many suggest
is getting into smartphone and tablet
sales and repairs. That’s not a silly idea
until you look at the nuts and bolts and
in fact, I seriously considered doing
that a few years ago when I first saw
the writing on the wall for computer
repairs. I even went so far as to set up
tentative import chains from Asia to
supply phones, tablets and even some
computer hardware.
On paper and in theory, this initially
looked very promising and I was extremely excited about the prospects.
I could buy low and sell high enough
to remain competitive and still make
money but it didn’t take long for the
cracks to start showing.
For a start, much of the hardware
wasn’t up to the quality that we’ve
come to expect. Most no-name phones
look the part in the glossy promotional
material and some even work quite
well for a while. However, they really
are built to a price and as such do
not stand up to everyday use as well
as their more-expensive brand-name
54 Silicon Chip
cousins. Out of a dozen of the best
quality phones I could find to import
and sell, every single one came back
within six months with problems
that would cost more to repair than
it would to simply replace the phone.
But that wasn’t the end of my problems, as I found out when I tried to
return them under warranty to the various suppliers. That’s when the system
really fell apart as not one vendor was
interested in helping to sort it out. In
the end, I wore the costs myself in an
effort to maintain credibility with my
customers. Apart from the damage to
my business, what really depressed me
was that my hopes had been dashed.
Importing and selling products in
this way was not the answer I was
looking for.
The fact remains that many of today’s “tech” devices are purposely
engineered to be consumable – that is,
to simply be replaced if or when they
fail. In my experience, most people
who bring in a phone or tablet with
a broken screen or some other fault
don’t want to spend more than a few
dollars to get it repaired. Indeed, most
are taken aback when they discover
the cost to replace an iPhone, iPad or
Samsung Galaxy screen, preferring
instead to use this as an excuse to go
and buy a new (and usually fancier)
phone. And I don’t blame them one bit.
Recent experience
A recent experience of my own illustrates why it just isn’t worth trying to
eke out a living by importing no-name
hardware from Asia or by offering to
fix high-end phones and tablets, no
matter how lucrative it may appear
to be on paper.
My wife and I both needed new
phones, with our old models years out
of date and “er-in-door’s” one finally
giving up the ghost. As a result, she
looked through some of the websites
of vendors we’ve dealt with before
online and found a brand-name phone
that was reasonably priced and which
boasted the features we both wanted.
It certainly looked good to me and
because it was branded and priced a
bit higher than some of the no-name
ones we’d seen in the past, we decided
to take a punt and order two of them
When they arrived, it certainly
looked like the gamble had paid off
because the phones were beautiful,
fast and had everything we could ever
want in a phone. Setting them up was
a breeze and transferring our data from
the old phones almost too easy, so it
wasn’t long before we both had our
respective phones on-line and in use.
But there was one small niggle:
Nina’s phone sometimes wouldn’t
hang up after making a call. The screen
initially wouldn’t respond to any touch
commands but after about 30 seconds
it would suddenly work and we could
then hit the “hang up” button. By
itself, it wasn’t a major problem but
it was annoying. What’s more, it soon
became apparent that the fault not only
occurred when making a call because at
other times, the screen would be nonresponsive for about 30 seconds before
suddenly becoming usable again.
At that point, I offered to swap
phones because my handset didn’t
exhibit any of those problems. Nina
uses dual SIM cards in her phone and
indeed one of the main reasons we
purchased this model was because of
the dual SIM feature, which allows
both work and private use in the
same handset. I don’t use two SIMs so
perhaps it was her use of dual SIMs
that was causing the screen “freezing”
problems in her phone?
After swapping the phones, she no
longer had problems but now I was
experiencing the screen “freezes”, so
it was definitely the phone that was
causing the problem and nothing to do
with running two SIM cards. Because
I mainly use my phone for business,
we swapped them back while I looked
into possible causes and solutions,
something that requires a lot perseverance due to the enormous amount of
information posted online in various
forums.
One disadvantage was that with
newer phones, there is often not much
information online but I looked anyway, in case someone else had experienced the same issue. The first place
I looked was on the phone manufacturer’s website and I downloaded their
“link” software, hoping I could use
this to install upgrades or troubleshoot
potential issues. Strangely though, I
couldn’t find our specific model listed
on the site and that rang a few warning
bells far off in the back of my mind.
The downloaded software “talked”
to the phone quite happily but informed me that there were no updates
siliconchip.com.au
available or required. And that appeared to be about the limit of the functionality of that particular program.
A little more research on the model
number, chip version and firmware
information took me to forums where
people were claiming that the phone
was fake and that the manufacturer
(and it looked increasingly like it
wasn’t who we thought it was) had
spoofed the hardware ID to make it
look like something it wasn’t. By that
stage, there were more alarm bells
going off in my head, only louder
this time.
About this time, just before Easter,
Nina decided to uninstall an app on
the phone because it was persistently
downloading unwanted games and
other rubbish – the bane of the modern
smartphone owner. Strangely, mine
didn’t do this and we had previously
tried using other apps we’d purchased
to “freeze” this games app. However,
it just seemed to circumvent any attempts at stopping it, which is why
she eventually decided to uninstall
it. Once it had been uninstalled, the
phone immediately rebooted but then
got stuck in a loop, with the Android
shell crashing then restarting, crashing
then restarting and so on.
Did I hear bells again? Yes, and they
were lot louder now . . .
Luckily, Easter was coming up and
I thought I’d use some of my spare
time (that I had intended to use to
make a valve amplifier project I’d
been planning) to tidy this phone up
and get it going again. And so, over
Good Friday, I spent many hours on
it, initially trying to get it going before
eventually resorting to restoring it to
its factory settings. It did this OK but
unfortunately, when I restarted it, the
shell was still crashing, so something
else had to be wrong.
Fortunately, I had an identical
phone and my reasoning was that I’d
find a utility to back up its ROM (ie,
the entire operating system and applications) and upload the file into
Nina’s phone. Problem solved – well,
that was the theory anyway.
Rabbit hole
This phone uses a chip-set called
“MTK” and some clever person has
written a set of tools specifically for
phones running this family of processors and has made it freely available for
download. Once I had this software,
it should then be a simple matter of
siliconchip.com.au
copying my ROM and then flashing it
back to Nina’s handset. But of course
there was a problem – and this is what
I’ve found when working on phones
and tablets; one problem leads to another, then to another and so on until I
could barely remember how far down
the rabbit hole I had gone.
The problem here was that since
we’d had these phones for a couple
of weeks before all this started happening, I had swapped the standard
Android KitKat bits and pieces that
came with the phone with a custom
one I’d used before on my old phone.
Simply put, this app stores the standard user interface into another folder
and replaces it with a new one, so that
every time the phone boots it loads the
new interface and leaves the old one
in storage. I’d also done this with the
web browser, SMS/Messaging app, the
standard file manager, the screen lock
(that bit when you wake the phone up
and swipe to unlock) and the phone
dialler, replacing them with custom
apps with more features.
Initially, I thought that when I
“ripped” my ROM to my hard disk, it
would pick those custom bits up and
take them along too but I was wrong.
All went well when I flashed Nina’s
phone via the USB interface but when
it booted, it didn’t have a user shell,
dialler, SMS, browser or file manager,
or any other component that I had customised on my phone. I could pull the
“shade” down and access the phone’s
settings but that was it.
If I’d had a file manager, I could have
found and installed the apps I needed
but I didn’t. And if I’d had a browser, I
could have used Google Play to download the apps and install them. But I
didn’t have any of those things and
nor could I get them onto the phone.
No problem, I thought, I’ll simply
restore my phone to standard, then
go through the same process, this time
flashing all the right bits and pieces to
get things going. The spanner in this
theory was that when I restored my
phone, it ended up doing the same
thing as Nina’s! Aaarrgghhh!
By this time, it was Saturday afternoon and I had spent many more hours
on this than I should have. What’s
more, I was further away from a result
than ever before. By now, Nina was
commenting on the amount of time it
was taking and I agreed; I needed to
resolve this problem. Unfortunately,
Google offered no relief – nobody had
any suggestions for the pickle I had got
myself into.
I slept on the problem and then
spent half of Sunday trying different
things, including installing Android’s
June 2015 55
Serviceman’s Log – continued
SDK (application development suite)
and using an ADB console (think DOS
prompt on Windows machines) to try
to “side-install” apps I’d previously
downloaded or found on my own
phone. I finally got it all connected but
every time I tried to install an “apk” file
(a standard Android app file), I got an
error stating that the “apk” was corrupt
and no matter what I did, I couldn’t
install any apps this way.
By Monday, I was thoroughly sick of
it and with two dead phones in front
of me, I sat back and took stock. I had
a ROM missing some components, so
I tried finding software to disassemble
and repack the ROM with the right
bits. I eventually found such software
and repacked the ROM but it wouldn’t
flash (more error messages and hair
pulled out).
And then I realised something; each
time I had restored a phone using the
MTKDroid tools app, it offered to
install a couple of utilities (unfortunately not the kind that would have
helped me out), side-loading them
via an automatic ADB console. This
system worked, so I hit upon the idea
of changing the three “apk” files it
was installing. Basically, I would get
it to install my file manager and web
browser “apk” files by renaming them
and putting them in the same folder
as the MTK “apk” files.
I did this and pressed the upload
button and . . . yes! The file manager installed and worked! The web browser
failed but when I renamed its files and
56 Silicon Chip
tried them one at a time, I managed
to install a locker, file manager, root
browser and web browser and thus
could finally download and install the
rest of what I needed
By this time, it was 7 o’clock in the
evening of Easter Monday. I finally had
the job done but when people ask me
what I did over Easter, I sheepishly
hold my tongue and just say that I had
a relaxing weekend!
The phones are working fine now
but this episode clearly demonstrates
why fixing phones and tablets isn’t a
viable career move. Aside from the
frustrations and the lost time that
could have been spent with loved
ones, there’s no way I could ever
charge enough for a job like that. I’ll
have to find another way.
Industrial machine servicing
Now for something completely different – servicing and refurbishing
industrial metal-forming machines.
G. S, of Montrose, Tasmania has some
interesting stories to tell . . .
In an earlier contribution, I mentioned that I have a small company
that designs controls for machines and
does factory automation. However, we
do get saddled with the odd service
job, especially when electricians draw
a blank.
One such case concerns a client I
have had for several years. He owns
a substantial building products company that makes roofing iron, gutters,
fascias and purlins etc. He has fairly
old machines that I have managed to
keep going by re-building the control
gear and he is also lucky enough to
employ a fitter who used to work for
a metal-forming machinery manufacturer. Between us, we can pretty much
get anything working but we get some
unusual legacy problems from the
previous owners at times.
Because my client has a lot of confidence in us, he is always purchasing
old machines that other manufacturers were looking to dump. Normally,
when a machine reached its use-by
date, the owner would purchase a new
machine then have the old one cut up
and scrapped, to prevent someone
getting it running and creating competition. However, because Tasmania
is viewed as a foreign land, we are not
seen as competition by the mainlanders who are usually only too happy to
sell their “junk” to us.
In one instance, I was summoned to
look at a “new” panbrake folder. This
was a monster that could bend nearly
eight metres of 3mm sheet. It also had
a hydraulic-powered slitter on its back.
An electrician had hooked it up
and it all seemed to run OK. However, when a fold was called for and
the apron began to swing, the clamp
would open slightly and release the
work piece. It turned out that this was
why the previous owner had got rid of
it. He had had it upgraded to carry the
slitter and it had not worked properly
since then.
Apparently, he’d had a number of
siliconchip.com.au
Before Modification
After Modification
Modifying & Repairing An Off-Grid Battery Charger
Deciding to fix something rather
than simply scrap it is often a gamble,
both in terms of time and money.
And of course, there’s never any
guarantee of success. Fortunately,
it was a gamble that paid off when
J. D. of Dubbo, NSW decided to repair
a faulty off-grid battery charger . . .
This story has two aspects: (1)
the actual technical challenge of the
repair and (2) the vexed question as
to whether the item concerned was
actually worth saving.
Basically, I have an off-grid system
supplying power to my house, or
more exactly, two identical systems,
with the house wiring split. One
system can keep us going at a pinch
if necessary. The entire system was
installed nearly 20 years ago and
has two separate battery chargers
(Woods Dialomatic 2440) connected
to a generator, so that batteries can
be used when it is cloudy for more
than a few days.
Both chargers had been faultless
until a couple of years ago when
they both failed about six months
apart. After some troubleshooting, I
determined that the problem in each
unit was on the mains control circuit
board. I then took them to a local
technician who replaced the boards
(at some cost), after which they again
functioned normally.
Although they are nearly 20 years
old, they do not see all that much
use. In the first year, for example,
they operated only about five hours.
Recently, one of them ceased
working again and as it was only a
siliconchip.com.au
year since the repair, I took it back
to the technician. A week or so later
I got a call to say that they could not
repair it, as the parts were no longer
available. I called the manufacturer
(yes, the units were Australian-made
and the company is still manufacturing equipment) and they told me that
there were only two parts not available for that model – the transformer
and rectifier. And yes, they had just
had an enquiry about a rectifier from
Dubbo.
Because I was an established
customer of theirs, they offered to
sell me a current-model replacement charger for just over $1000.
Although my chargers are only about
20 years old, the design is actually
about 40 years old according to the
manufacturer
I picked up my charger from the
local technician the following day
and he offered a replacement charger,
a little smaller and presumably made
in China, for $600 or thereabouts.
However, for the time being, I decided to see if anything could be
done to resurrect the faulty unit.
After all, what could be so special
about the rectifier?
Once home, I pulled the covers off
and examined the unit. The transformer actually has two secondary
windings and the rectifier is in fact
two separate half-wave rectifiers,
each comprising two diodes soldered
to 150mm lengths of 19mm-diameter
copper pipe. The copper pipes act
as heatsinks and the whole lot is
assembled onto a fibreglass board.
At least one of the diodes had
shorted internally and the resulting
heat had melted the solder, disconnecting the diode from its copper
pipe and disconnecting the negative
battery lead in the process. So it was
no wonder that the charger had failed
completely. The problem was, how
could it be fixed?
After going through the Jaycar
catalog, I decided to try using two
BR354 35A bridge rectifiers with
their outputs paralleled. And to keep
them cool, these would be mounted
on the largest alloy heatsink that
would fit in the available space.
These parts duly arrived and it
was then just a matter of assembling
everything in the case. This wasn’t
quite as easy as it sounds though,
since very heavy wiring is required
throughout. Once the job was finished, the charger was tested and
reconnected and it then functioned
normally for an entire tank of fuel in
the generator.
This repair probably took about
four hours of work but that included
scratching around in the shed for
suitable wire, tags, bolts, etc. I also
spent a total of $43 for parts which
is considerably less than the replacement cost for the charger.
So why didn’t the technician repair it the way I did? I can see a few
reasons, including liability, lack of
time and warranty issues. However,
it does make you wonder just how
much equipment gets scrapped
when it could be repaired for much
less than the cost of replacing it.
June 2015 57
Serviceman’s Log – continued
people look at it with no result, so
in the end he decided to dump it.
However, my client heard about it
somehow and offered him a few dollars for it. In fact, it actually cost him
more to ship it.
Anyway, I watched what it was
doing and it looked like the problem
was in the PLC (programmable logic
controller) program, as it was sending
a short pulse to the “open” hydraulic
valve on the clamp every time a fold
was called for. This made it awkward
as I didn’t have the tools to program
this particular species of PLC. Nor did I
feel inclined to spend a heap of money
on the programming tools.
This called for some lateral thinking.
As the problem only occurred when the
apron was asked to swing, the obvious
answer was to block the clamp-open
valve during the swing. As a result, I
added a relay across the apron valve,
with its normally closed contact in
series with the clamp-open valve.
That solved the problem and the
customer was happy with his purchase.
With that job out of the way, I was
then asked to take a look at a machine
that rolled corrugated roofing. This
had been acquired a few years previ-
ously and it had been a mess, with the
control box containing a rat’s nest of
oil-soaked wires. Many of these wires
did nothing, having been replaced but
never pulled out.
At the time, I rebuilt the control box
and rewired it. The hydraulics were
also replaced so there was not much
left to go wrong except the Pegasus
electronic controller.
It turned out that this controller
was now the problem, as the display
was faulty. A cursory glance through
the display window revealed that the
vacuum fluorescent display was covered in cracks.
After a few “subtle” questions, the
machine’s operator admitted that the
display had been intermittent the past
few days and it had blinked out in the
middle of a large job. He was under a
bit of stress at the time and he took it
out on the controller with his fist. It
must have been pretty good effort to
crack the display though, considering
it was behind a thick polycarbonate
window.
Fortunately, Pegasus is a good, welldesigned (and still manufactured)
Australian product, so we were able to
get hold of a new display overnight. It
is very easy to get into the controller,
Servicing Stories Wanted
Do you have any good servicing stories that you would like to share in The Serviceman column in SILICON CHIP? If so, why not send those stories in to us? In doesn’t
matter what the story is about as long as it’s in some way related to the electronics
or electrical industries, to computers or even to car electronics.
We pay for all contributions published but please note that your material must
be original. Send your contribution by email to: editor<at>siliconchip.com.au
Please be sure to include your full name and address details.
58 Silicon Chip
by removing just four nuts. All the connectors are plug-in and the main PCB
can be removed in a couple of minutes.
This reveals the back of the display,
which is held in place with a couple
of screws. It all fits together with a
SIL socket on the main PCB lining up
with long SIL pins on the display. A
similar arrangement is used to connect
the controller’s keypad.
The connector on the board was
the source of the intermittent display
operation. It had loose contacts and
vibration from the machine was causing them to go open circuit, usually at
inconvenient times. It was a simple
matter to replace it.
I then turned my attention to the
broken display which was well and
truly shattered. It came out easily and
I tried to simply drop the new one in
place. I found it all lined up OK but
it didn’t feel right, as it seemed to go
down against a hard surface when it
should have had some clearance. I
removed it and took a closer look with
a head magnifier (my eyes are not what
they used to be) and found the remains
of another display still in place.
It turned out that someone had
earlier glued this display directly to
the polycarbonate window. When this
display was damaged, they chipped
out as much as they could and simply
put a new one on top of the wreckage,
screwing it down tightly and thus giving it no protection against impact.
Using an electrician’s hammer and
chisel (ie, pliers and screwdriver), I
carefully chipped out all the remains.
This then allowed the new unit to fit
properly and there were no further
issues.
Purlin roll formers
Some time after that, my client
purchased three Purlin roll formers
that allowed him to cover 150, 200
and 250mm sizes and save the ongoing issue of changing dies in the only
machine he had. These things run to
six figures each but he managed to buy
the lot for five figures delivered and
“could I get them running?”. Getting
them so cheap was cause for worry
but I said I’d see what could be done.
When I turned up, I was surprised to
find two very nice-looking machines
that had already been installed, while
the third one was under a tarp in the
yard waiting for a new building to
house it. They were Chinese-made, all
built to a common footprint about 12
siliconchip.com.au
metres long and all using an 18kW hydraulic power pack and a 15kW motor
to drive the rollers. This seemed a bit of
a waste, as the hydraulic pump could
have easily done both jobs. There was
also no brake on the machines which
I found rather strange.
The control box used a panel PC
running a SCADA package. It had nice
graphics and a PLC to do the thinking,
along with a hefty VSD (variable speed
drive) driving the roller motor. All this
was housed in a desk console which
had spent time in the rain, as no one
felt the need to worry about something
heading to the scrap yard.
There was no-one to go to for information so I was on my own. It also
turned out that the previous owner
had given up as he couldn’t get a good
result from them, even after getting the
controls rebuilt locally. This was not
looking good.
In fact, this was no longer a service
job but a total rebuild. In the end, I
designed a control PCB using a Comfile Technologies Cubloc device. This
has two high-speed counters and with
appropriate I/O is ideal for control
jobs like this. It sent serial data to
a 250mm Comfile display mounted
behind a 6mm polycarbonate window (these are actually touch panels
but it’s safer to keep fingers [fists!] off
them), while the input came from a 16button Storm keypad.
This was all mounted on the door of
a new control enclosure. In addition,
this enclosure contained all the necessary bits to run the machine, including
a star/delta starter for the hydraulic
pump and a new Bonfiglioli VSD for
the roller motor.
The VSD was chosen as it has builtin algorithms to operate cranes. These
give it the ability to accurately park
using electronic and mechanical braking while under heavy load (which I
was sure we were going to need). I
also added Sick safety lock-outs and
emergency stop relays which for some
reason the manufacturer failed to fit to
the guards.
The theory of operation of a roll former is pretty simple. It punches holes
and cuts to length using a counter attached to a device that gives a pulse
for every millimetre travelled. Fairly
obviously, it has to be accurate.
We rebuilt the first machine, replaced all 62 bearings and fired it up.
Apart from the hydraulic hose connections being crossed over, everything
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did as it should – or so we thought.
We ran a test length of four metres
and found it was out by 80-plus millimetres. I then adjusted the speed
control so that it ran fast but slowed to
a crawl when it got to within 100mm
of a stopping point.
I also programmed it for impressed
current braking which slows the motor quickly by driving high-current DC
into the motor for a couple of seconds.
This reduced the discrepancy to
17mm, however subsequent runs gave
differing values over and under the
target value. We watched the motor
and found it still did a lot of revs after
the stopping point before coming to a
halt, even with DC injection. It also
rolled back several revs due to slack
in the chain drives and probably the
2-tonne roll of steel strip pulling it
back. It was plain that a real motor
brake was needed.
An after-market brake was purchased and the fitter made up appropriate adapters. This time the measurements were inaccurate but consistent,
so the brake was doing its job.
We now turned our attention to the
rotary encoder, which uses a wheel
pressed against the strip. This should
allow the encoder to deliver one pulse
for every millimetre of strip, provided
the wheel is the correct diameter. It
wasn’t so the fitter got to work and
produced a wheel that was about as
close as was possible with the tools
available. This closed the discrepancy
to within a few millimetres.
We solved that last discrepancy by
using a new encoder manufactured by
Sick. This thing is pure genius as it’s
possible to program the output pulses
per rev – up to 10,000. We finished up
with 1999 pulses per rev and with a
few software tweaks it gave us better
than 1mm accuracy in a 10-metre run
which was good enough.
As can be imagined, it all took quite
a long time to get everything right but
the machine now accurately measures
and punches. What’s more, my client
still spent less than half the cost of a
new machine while getting a “better
than new” machine.
We now have to refurbish the remaining two machines but that’s not the end
of it. My client has just announced that
he’s acquired a top hat Purlin roller
of the same design. “It’s been sitting
outside for a while”, he told me, “but
I reckon you should be able to get it
SC
going, don’t you think?”
Introduction
to PCBs
Part 2: How to read and understand a PCB manufacturer’s
technical capability statement
Imagine sending a PCB design to a
manufacturer but they ask for some changes
to suit their manufacturing capability. How
would you feel when these changes take
days to implement and disturb your project
planning? Extremely frustrating!
Here are some tips to avoid this:
1. If your manufacturer has separate
capability statements for prototype and
production manufacturing, please ask for a
copy and refer to the correct one. It is possible to manufacture small-volume PCBs
with tighter tolerances so if you require
PCBs in small numbers, you may choose
their tightest capability statement.
2. The three basic limitations are:
(a) Etching limitation: (ie, minimum track
width/spacing). For 1oz standard finish, 5-6
mil (i.e. 0.127-0.152mm) is the minimum
track width and spacing. With special attention, 3.5-4 mil (i.e. 0.089-0.102mm) can
be achieved on small to medium volume
production. Thicker copper can increase the
clearance requirements up to 12 or 13mils.
(b) Hole size limitation: Most manufacturers accept finished hole sizes from 0.3mm
to 6.35mm as standard. Some manufacturers charge extra for 0.25mm finished holes
(standard for QualiEco Circuits). A few
manufactures can also accept 0.25mm,
0.2mm or even 0.15mm by paying extra.
Holes less than 0.15mm are only possible
by laser drilling, which is quite expensive.
(c) Bonding & drilling limitation: (for
multilayer PCBs only). Keep in mind the
gap between edge of the hole and nearest
copper area (track/pad/pour) in inner layers.
For multi-layer PCBs, drilling is performed
after bonding so this criterion is extremely
critical for PCB manufacturers, as is plating
tolerance.
3. Minimum copper and solder mask pad
size around holes:
(a) Copper pad size – most manufacturers define copper pads around holes as
“annular ring”. There is a minimum annular
ring size you need to maintain everywhere
in the design.
(b) Solder mask pad size – a solder mask
prevents solder bridges between adjacent
pads and traces during soldering process.
Most manufacturers define them as “mask
openings” which are slightly larger than
the pads.
Brought to
you by the
technical
team at
pcb<at>qualiecocircuits.com.au
siliconchip.com.au
June 2015 59
Audio Signal
Injector & Tracer
. . . with optional tiny add-on RF probe
This Audio Signal Injector/Tracer is ideal for
troubleshooting AM radio and audio circuits.
It comprises a 1kHz oscillator (the Injector)
and an in-built preamp and amplifier with a
headphone jack (the Tracer) so you can trace
signals right through an amplifier or radio
circuit to locate faults.
By JOHN CLARKE
This photo shows the complete Audio Signal Injector/Tracer
together with its optional RF Demodulator Probe at right.
A
T SOME STAGE, everyone involved in electronics will need
to find a fault in an audio circuit. It
might be a circuit you have just built,
a repair job for a friend or a job to be
done in your workplace. And while
you can often check voltages if you
have a circuit diagram, sooner or later
Main Features
• Hand held & battery powered
• 1kHz injector output
• Adjustable injector level
• Tracer input attenuator
• Tracer volume control
• Audio output to headphones or
small speaker
• Low battery indication
• Optional RF probe for AM
modulation detection
60 Silicon Chip
you will probably need to trace the
progress of an actual signal though the
various stages.
For example, you might feed a signal
into the input and then find that it
disappears as it feeds through a capacitor. The obvious conclusion would
be that the capacitor is faulty (open)
or it has not been properly soldered
into circuit.
To do this sort of fault-finding, you
need a suitable signal (one you can
hear) and a small amplifier so you can
listen to the signal at various stages in
the amplifier or AM radio being tested.
So our Audio Signal Injector/Tracer
has a 1kHz oscillator as the Injector
and a small amplifier as the Tracer.
AM radio adds an extra complication because you need to listen to a
modulated radio signal as it goes from
stage to stage in the circuit. For that
you need an optional RF demodulator
probe and we show how to build one
in the article on page 68 of this issue
– it’s tiny!
Mind you, if you are repairing an
amplifier, you may not need the Injector’s audio signal, provided you have
a CD player or even a smart phone
which has music tracks.
One the other hand, a music signal is
not always ideal if you are using an oscilloscope and want to see if the signal
becomes distorted at a particular stage
in the circuit. In that case, you might
find the Injector more convenient as
you trace a signal of known shape
through the circuit.
As mentioned, our Injector is a
1kHz oscillator and you can see the
shape in the accompanying scope
grab designated Scope 1. It looks a
bit like a sinewave but is actually a
somewhat “rounded” square wave. It
has a maximum amplitude of about
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The Audio Signal Injector/Tracer is ideal for tracking
down faults in audio amplifiers and preamplifier stages.
And by adding the optional RF Demodulator Probe, it
can be used to trace signals through the RF stages of
AM radios as well. You can listen in to the traced signal
via either headphones or an external speaker but the
latter should be used if checking high-voltage circuits.
Specifications
2V RMS but it can be adjusted down
to just few millivolts.
This means that it will cover virtually all signal tracing situations, from
sensitive audio preamplifiers and the
audio sections of AM/FM radios, right
up to high-powered guitar and public
address amplifiers.
Then we come to the Signal Tracer.
It needs a small amplifier to listen to
small signals in sensitive circuits but it
also needs an input attenuator so that
it is not overloaded by the much larger
signals, perhaps 50V or more, that you
might find in a high-powered amplifier. You also need a volume control
so that your ears are not blasted as you
step through a circuit.
Finally, both the Injector and Signal
Tracer need to be protected from any
high voltages that may be present in
a solid-state or valve circuit. If you
feed the Injector into a circuit operating at 300V DC, for example, you
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Power: 9V at 2.3mA
Tracer input impedance: ~6.45MΩ to 10MΩ, depending on attenuator setting
Tracer signal gain: adjustable from 2x to 20x
Tracer attenuator: 1:1, 1:10, 1:100 & 1:1000
Tracer signal frequency response: 70Hz to 3kHz
Injector signal: 1kHz rounded square-wave
Injector signal level: adjustable from 0-2V RMS (5.6V peak-peak) with a 9V supply
Headphone output: 6.6V peak-peak maximum into 16Ω with a 9V supply
Test circuit DC voltage: ±300V DC maximum recommended
don’t want it to be blown to shreds
and by the same token, if you touch
the Tracer probe onto a similar highvoltage point, you don’t want it to be
“cooked”. Our circuit takes care of
those possibilities.
Our Injector/Tracer is housed in a
compact plastic case with an internal
battery compartment. It has a pair of
jack sockets for the output of the Injector and a BNC socket for the input
to the Tracer. Next to that socket is a
4-position slide switch for the Attenuator which has settings of 1:1, 1:10,
1:100 and 1:1000.
Input impedance
The input impedance of the Tracer
is rather high, varying between about
10MΩ and 6.45MΩ, depending on
the setting of the input attenuator.
This means that the impedance of the
June 2015 61
Scope 1: the 1kHz waveform generated by the oscillator
looks a bit like a sinewave but is actually a “rounded”
square wave. It has a maximum amplitude of about 2V
RMS but can be adjusted down to just a few millivolts.
Tracer will not load down or affect the
operation of the circuit being tested.
The high-impedance input also means
that the Tracer probe can be used to
directly test ceramic (crystal) phono
cartridges or piezoelectric pick-ups on
musical instruments such as a violins.
To connect signal to the Tracer you
can use a 1:1 oscilloscope probe or
any shielded cable with a BNC plug
at one end and a suitable connector
at the other, such as an RCA plug or a
pair of alligator clips. More about this
later in the article.
The on/off switch, a power LED and
the two knobs for the Injector level
Warning!
When using the Audio Signal
Injector/Tracer with high-voltage
circuitry (eg, in a valve radio), take
care not to touch any part of the
circuit with your hand. Always treat
the circuit as though it has mains
voltage present.
As stated in the article, use a
small extension speaker rather than
headphones when using the unit
with high-voltage circuitry. Small
non-powered extension speakers
are available for use with iPods and
similar MP3/MP4 players.
The use of a small speaker will
remove the possibility of deafening
clicks or even a high-voltage shock
should there be a fault within the
Audio Signal Injector/Tracer or if the
earth lead becomes disconnected.
62 Silicon Chip
Scope 2: this scope grab shows the Schmitt trigger operation
of IC1a. The yellow trace shows the charging and discharg
ing of the 6.8nF capacitor from 3V to 6V etc, while the green
trace shows the resultant square-wave output at pin 1.
and Tracer volume controls are at
one end of the case while the 3.5mm
headphone jack is on the side, adjacent
to the 4-position Attenuator switch.
Circuit description
Let’s now take a look at the circuit
of the Audio Signal Injector/Tracer –
see Fig.1.
As shown, it’s based on an LMC
6482AIN CMOS dual rail-to-rail op
amp and a handful of other components. One op amp is used for the
Signal Injector while the other is used
for the Tracer. The output frequency
of 1kHz is set by the 100kΩ resistor
and 6.8nF capacitor connected to pin
2, the non-inverting input.
The three resistors connected to the
pin 3 inverting input set the threshold
voltage (at pin 3) at 1/3Vcc or 2/3Vcc,
depending on whether the output of
IC1a is high or low. So with Vcc = 9V,
the input (threshold) voltage at pin 3
will be either +3V or +6V.
When power is applied to the circuit, the 6.8nF capacitor at pin 2 will
be discharged (ie, 0V), so pin 2 will be
lower than pin 3. Therefore the output
at pin 1 will be high (+9V) and this
charges the 6.8nF capacitor via the
100kΩ resistor between pins 1 & 2.
When the capacitor voltage rises just
above 6V, pin 2 becomes higher than
pin 3 and so the op amp’s pin 1 output
switches low, to 0V (remember, this is
a “rail-to-rail” op amp).
So now pin 3 is at 3V and the
capacitor discharges via its 100kΩ
resistor until pin 2 is just below pin
3, whereupon the pin 1 output goes
high again to recharge the capacitor.
This continuing cycle generates a 1kHz
square wave which is filtered using a
6.8kΩ resistor and 22nF capacitor to
give a “rounded” waveform, as shown
in Scope 1.
The Schmitt trigger operation of IC1a
is demonstrated in Scope 2, which
shows the charging and discharging of
the 6.8nF capacitor from 3V to 6V etc
in the yellow trace. The lower green
trace shows the resultant square-wave
output at pin 1. Note that the amplitude
of the square-wave is shown as 9.8V –
we used a fresh 9V battery.
Potentiometer VR1 connects across
the 22nF capacitor to provide the Injector level control. This is AC-coupled to
the output terminal via a 100nF 630V
capacitor. We specified a high voltage
rating for this capacitor so that the
Injector output can be connected to a
high voltage on the circuit under test
without damage.
For the same reason, diodes D2 &
D3 clamp any high voltage from an
external circuit (eg, a valve radio being tested) at the wiper of VR1 to 0.7V
above or below the 9V and 0V supply
rails. The 10MΩ resistor across the
100nF capacitor is there to discharge
the capacitor when it is disconnected
from the circuit under test. The 1kΩ
resistor in series with the Injector output limits peak current to the clamping
diodes.
Tracer circuit
The input signal from the BNC
siliconchip.com.au
POWER
D1 1N5819
+9V
A
100k
100k
K
IC1: LMC6482AIN
3
1
IC1a
2
100k
100k
D2
A
6.8k
INJECT
LEVEL
VR1
10k
LIN
22nF
100nF
K K
INJECT
OUT
1k
100nF
16V
A
2.2k
GND
10M
D3
BANANA
SKT
A
BC 327, BC33 7
+9V
B
K
BNC
TRACER
INPUT
D4
100k
9.1M
910k
91k
1:1
ATTENUATOR
S2
1nF
100k
A
10M
1:10
E
8
5
7
IC1b
6
4
E
1:100
1:1000
C
10M
2.7k
A
100k
10 µF
16V
100 µF 16V
CON1
Q1
BC327
3.5mm
JACK
SOCKET
100k
VR2
50k LOG
D1: 1N5819
1 µF
16V
A
VOLUME
LED1
2.7k
K
A
SC
C
220pF
D5
10k
20 1 5
Q2
BC337
620Ω
B
K
E
C
B
1kV
9V
BATTERY
ZD1
5.6V
100 µF
BANANA
SKT
630V
K
6.8nF
A
K
S1
λ LED1
AUDIO SIGNAL INJECTOR & TRACER
K
ZD1
A
K
D2–D5: 1N4004
A
K
Fig.1: the circuit is based on dual op amp IC1. IC1a operates as a Schmitt trigger oscillator and this generates the
injector signal, with VR1 setting the output level. The traced signal is fed in via a switched attenuator and then fed to
op amp IC1b. Its output signal is then buffered by Q1 & Q2 and fed to CON 1, while VR2 sets the op amp gain.
socket is fed to 4-way slider switch,
S2 and the attenuator resistors. The
resistors provide for division ratios of
1:1, 1:10, 1:100 and 1:1000.
Following S2, the signal is coupled
via a 1nF 1kV ceramic capacitor to
the pin 5 non-inverting input of IC1b.
This is tied via two series-connected
10MΩ resistors to a voltage divider
(two 100kΩ resistors) which provides a
reference at 4.5V ie, half the 9V supply.
Diodes D4 & D5 clamp any high
voltage input signals to 0.6V above or
below the 9V supply rails.
IC1b is connected as a non-inverting
amplifier and its pin 7 output drives
a complementary emitter follower
stage using transistors Q1 & Q2. These
provide a buffered output to the headphone socket via a 100µF coupling
capacitor.
Note that the emitter follower output
stage is operated with no quiescent
siliconchip.com.au
current but is within the negative feedback loop of the op amp to minimise
crossover distortion.
The 50kΩ volume control (VR2) is
also in the op amp’s feedback loop,
connected in series with a 2.7kΩ
resistor. In conjunction with the 1µF
capacitor and series 2.7kΩ resistor
from pin 6 to 0V, this allows the AC
gain to be varied from between two and
20. The DC gain is unity, by virtue of
the 1µF capacitor.
Note that while the amplifier is
mainly intended to drive headphones,
it can also be used to drive a small
speaker and we recommend this if
you are doing signal tracing in a highvoltage circuit which might cause
deafening clicks when you touch the
probe on high voltage points.
ates from a 9V battery, fed in via toggle
switch S1. Diode D1 gives protection if
the battery is inadvertently connected
the wrong way around. A high-intensity red LED is used for power indication. It is bright when the supply is at
9V but drops to a dim glow when the
battery is flat, by virtue of ZD1, a 5.6V
zener diode in series with the LED.
When the battery is fresh, ie, putting out 9V or maybe as much as 10V,
we will have 1.8V across the red LED,
5.6V across ZD1 and 1.6V or more
across the 1kΩ resistor so that 1.6mA
or more flows through LED1. As the
voltage falls, the voltage across the
1kΩ resistor also falls. At a battery
voltage of 7.4V or less, there is very
little voltage across the 1kΩ resistor
and so LED1 will be dim.
Power supply
RF demodulator probe
As already noted, the circuit oper-
As previously noted, if you want
June 2015 63
VR1
100 µF Q2
+
This photo shows how switch S2 is
mounted. It’s soldered to a pin header
so that its top metal face is 12.5mm
above the PCB.
BC337
620Ω
2.7k
4004
4004
D5
1kV
220pF
2.7k
1 µF
D4
LMC6482
100k
6.8k
100k
2.2k
D3
22nF
Q1
PHONES
Inject
fitted. These are installed at the five
external wiring points, at TP GND
(near LED1) and at the bottom right of
S2. IC1 can then be soldered in place.
Do not use a socket for this IC, as this
would exacerbate noise pick-up.
CON1
100k
10M
10M
100k
1k
4004
S
100nF
630V
–
(-)
TO BATTERY CLIP
to troubleshoot an AM radio with
the Tracer, you need to have an additional demodulator probe for the
amplitude-modulated (AM) RF signals
that should be present in the circuit
being tested. As stated, a suitable RF
demodulator probe is described on
page 68 of this issue.
Construction
The Audio Signal Injector/Tracer
is built on a double-sided PCB coded
04106151 (85 x 63mm). This is housed
in a plastic remote control case measuring 135 x 70 x 24mm. A panel label
measuring 114 x 50mm is attached to
the front of the case.
To make the assembly easy, the PCB
100k
TO SHIELD PCB
10k
S2
91k
+
910k
9.1M
10M
+
GND
Tracer
GROUND
SOCKET
1nF
R
TRACER
INPUT
BNC SOCKET
10 µF
T
CUT LUGS
SHORT
(SEE TEXT)
AUDIO SIGNAL INJECTOR & TRACER D2
INJECTOR
OUTPUT
SOCKET
4004
6.8nF
+
100 µF
100k
100k
5 V6
ZD1
100k
TP GND
D1
50k LOG
10k LIN
100nF
BC327
LED1
S1
VR2
15160140
K
IC1
A
5819
Fig.2: follow this parts
layout diagram to build
the PCB assembly. Be sure
to install the 100nF 630V
and 1nF 1kV capacitors in
the positions indicated and
note that S2 is mounted on
a pin header (see photo).
/1
/10
COM
Installing switch S2
/100
/1000
Switch S2 does not mount directly
onto the PCB but is instead raised off
the PCB using a 6-way DIL pin header.
Before installing this DIL header,
remove a pin from each side so that
there are three pins, then a gap, then
two pins (ie, on each side of the header
to correspond with the switch pins).
That done, position the header on
the PCB with the longer pins facing
upwards, then push each pin down so
that it extends only 5mm above the top
of the PCB. The pins on the underside
EARTH PC STAKE FOR
S2's METAL COVER
is designed to mount onto the integral
mounting bushes within the case. The
top of the PCB is also shaped to fit
around the case mounting pillars at
that end – see Fig.2 and photo.
Fig.2 shows the parts layout on the
PCB. Begin by the installing the resistors. Table 1 shows the resistor colour
codes but it’s also a good idea to check
each one with a digital multimeter
before soldering it to the PCB.
The diodes can go in next. Note that
there are two different types – D1 is a
1N5819, while D2-D5 are 1N4004s. Be
sure to mount them with the correct
polarity, then install zener diode ZD1,
again taking care with its polarity.
The seven PC stakes can now be
Table 2: Capacitor Codes
Value µF Value IEC Code EIA Code
100nF 0.1µF 100n 104
22nF 0.022µF 22n 223
6.8nF 0.0068µF 6n8 682
1nF 0.001µF 1n 102
220pF NA 220p 221
Table 1: Resistor Colour Codes
o
o
o
o
o
o
o
o
o
o
o
o
No.
3
1
1
8
1
1
1
2
1
1
1
64 Silicon Chip
Value
10MΩ
9.1MΩ
910kΩ
100kΩ
91kΩ
10kΩ
6.8kΩ
2.7kΩ
2.2kΩ
1kΩ
620Ω
4-Band Code (1%)
brown black blue brown
white brown green brown
white brown yellow brown
brown black yellow brown
white brown orange brown
brown black orange brown
blue grey red brown
red violet red brown
red red red brown
brown black red brown
blue red brown brown
5-Band Code (1%)
brown black black green brown
white brown black yellow brown
white brown black orange brown
brown black black orange brown
white brown black red brown
brown black black red brown
blue grey black brown brown
red violet black brown brown
red red black brown brown
brown black black brown brown
blue red black black brown
siliconchip.com.au
can then be soldered to their respective
pads, making sure that the header itself
is flush against the PCB.
Once it’s in position, switch S2
can be mounted by soldering its pins
to the top of the header pins, so that
its top metal face sits 12.5mm above
the PCB (see photo). The best way to
do this is to lightly tack-solder two
diagonally-opposite pins first, then
make any necessary adjustment before
soldering the remaining pins. Don’t
forget to resolder the first two pins, to
ensure reliable connections.
Once it’s in position, the adjacent
earth PC stake is soldered to the earth
tag on S2’s metal cover.
Completing the PCB
Now for the capacitors. Install the
100nF 630V polyester and 1nF 1kV
ceramic capacitors in the positions
shown, then install the remaining
MKT polyester types. The electrolytics
can then go in, taking care to fit each
one with the polarity as indicated on
Fig.2. Note that the tops of the electrolytics must be no more than 12.5mm
above the PCB, otherwise you will not
be able to fit the case lid later on.
Follow with potentiometers VR1
& VR2, toggle switch S1 and the
3.5mm socket. VR1 is a 10kΩ linear
potentiometer while VR2 is a 50kΩ
log potentiometer, so don’t get them
mixed up. LED1 can then be installed
– it mounts horizontally with its leads
bent down through 90° exactly 7mm
from its lens, so that they go through
the PCB pads. Push it down so that
its horizontal lead sections sit exactly
6mm above the PCB (use a 6mm-wide
cardboard spacer) and check that it is
correctly orientated before soldering
it to the PCB.
That completes the PCB assembly. It
can now be checked and placed to one
side while the case is drilled.
Preparing the case
Figs.3 & 4 show drilling templates
for the front panel and for the top of the
case. They can either be photocopied
from the magazine or downloaded as
PDF files from the SILICON CHIP website
and printed out.
It’s just a matter of cutting the templates out, temporarily attaching them
to the case panels and then drilling
the various holes. The top of the case
requires holes for potentiometers VR1
& VR2, switch S1 and LED1, while the
front panel is drilled to accept the two
siliconchip.com.au
banana sockets, the BNC socket and
slide switch S2.
The rectangular cut-out for S2 is
best made by drilling a row of holes
inside the cut-out area, joining these
and then filing the job to shape. The
two banana socket holes can simply
be drilled and reamed to size but the
BNC socket hole needs to be shaped
as shown on the template. It can be
made by first drilling a small hole in
the centre, then finalising its shape
using small files, with the flat side
positioned as shown.
A hole must also be cut in one side
of the case to accept the 3.5mm jack
socket. To do this, temporarily position the PCB in the case, mark out
the socket position, then remove the
board and make a semi-circular notch
in the base using a small round file.
Once that’s been done, temporarily
assemble the case and complete the
hole by filing a matching semi-circular
cut-out in the lid.
Finally, you have to remove an
internal pillar inside the case lid so
that it doesn’t foul the nut for the
earth banana socket. This can be done
using side cutters. Note also that, as
provided, the banana socket terminals
are too long for the case and have to
be shortened by 5mm. A fine-tooth
hacksaw blade is the best tool for this
job – do not bend the terminals, as they
will break. File off any sharp edges
after cutting them to length.
Having drilled all the holes, the
front panel label can be attached. This
can be downloaded from the SILICON
CHIP website, printed out (preferably
onto photo paper) and affixed to the
lid using either glue or neutral-cure
silicone.
Alternatively, for a more rugged
label, print it out as a mirror image
onto clear overhead projector film (be
sure to use film that suits your printer),
so that the printed side will be on the
back of the film when the label is affixed. The film will have to be attached
using a light-coloured silicone applied
evenly over the surface, as the lid is
black.
Another option is to print the
panel onto either an A4-size “Dataflex”
sticky label (for ink-jet printers) or a
“Datapol” sticky label (for laser printers) and directly attach this to the case
lid. These labels are available from
http://www.blanklabels.com.au and
sample sheets are available on request
to test in your printer.
INJECTOR
OUT
+
TRACER
VOLUME
INJECT
LEVEL
POWER
WARNING!
Do not use
headphones
or earbuds
when testing
high voltage HEADPHONES
circuits.
Use extension
speaker instead.
1
10
100
1000
+
+
GROUND
TRACER
IN
TRACER
ATTENUATOR
SILICON CHIP
Audio
Signal Injector
& Tracer
Fig.3: this front-panel artwork can
be copied or downloaded from the
SILICON CHIP website and used as a
drilling template.
End Panel Drilling Guide
5mm 3mm
7mm
7mm
Fig.4: the end panel drilling template.
Drill pilot holes first to ensure they are
accurately positioned, then carefully
enlarge them to size.
Once the label is in position, cut out
the holes using a sharp hobby knife.
Making a shield PCB
Since the tracer has such a high
input impedance, it has the potential
to pick up hum from transformers but
it will also pick up the injector signal
as well, due to direct radiation of the
injector signal into the input attenuator and other components in the op
amp’s input circuitry.
We can reduce this by a significant
amount by installing a small shield
board, made from copper laminate,
underneath the PCB, with its copper
side earthed to the PCB’s GND stake.
The dimensions of this shield board
are shown in Fig.5. It fits between the
June 2015 65
Parts List
1 remote control case, 135 x 70 x
24mm (Jaycar HB-5610)
1 double-sided PCB, code
04106151, 85 x 63mm
1 single-sided shield PCB, code
04106153, 62 x 63mm
1 panel label, 114 x 50mm
1 9mm square PCB-mount 10kΩ
linear potentiometer (VR1)
1 9mm square PCB-mount 50kΩ
log potentiometer (VR2)
1 SPDT PCB-mount toggle switch
(Altronics S1421) (S1)
1 DP4T PCB-mount slider switch
(TE Connectivity STS2400PC04)
(element14 Cat. 1291137) (S2)
1 PCB-mount 3.5mm stereo jack
socket (CON1)
2 knobs to suit VR1 & VR2
1 panel-mount BNC socket
1 blue insulated banana socket
(Jaycar PS-0423)
1 green insulated banana socket
(Jaycar PS-0422)
1 9V alkaline battery
1 9V battery snap connector
4 No.4 x 6mm self-tapping screws
7 PC stakes
1 DIL 6-way pin header
7
7
7
7
ALL DIMENSIONS IN MM
62
BLANK PCB
COPPER ON UNDERSIDE
20
Semiconductors
1 LMC6482AIN dual CMOS op
amp (IC1)
1 3mm high-intensity red LED
(LED1)
1 BC327 PNP transistor (Q1)
1 BC337 NPN transistor (Q2)
1 5.6V 1W zener diode (ZD1)
1 1N5819 Schottky diode (D1)
4 1N4004 diodes (D2-D5)
Capacitors
2 100µF 16V PC electrolytic
1 10µF 16V PC electrolytic
1 1µF 16V PC electrolytic
1 100nF 630V polyester
1 100nF 63V or 100V MKT polyester
1 22nF 63V or 100V MKT polyester
1 6.8nF 63V or 100V MKT polyester
1 1nF 1kV ceramic
1 220pF disc ceramic
Resistors (0.25W, 1%)
3 10MΩ
1 6.8kΩ
this, solder a short piece of wire to
the copper side and then connect its
other end to the earth pin (GND) for
the BNC connection, on the PCB. The
shield PCB is then secured inside the
case using silicone adhesive.
Final assembly
63
28
7
4
Fig.5: this diagram shows the dimen
sions of the blank shield PCB.
four integral pillars used to mount the
PCB and it has a cut-out to clear the
back of the Injector jack sockets.
Alternatively, if you don’t wish make
your own shield board, you can buy
a ready-made board from the SILICON
CHIP Online Shop (code 04106153).
The shield board is installed in
the case with its copper side facing
downwards, away from the underside
of the PCB (otherwise it would short
the component pigtails!). Before doing
66 Silicon Chip
1 150mm length of hookup wire
1 50mm length of single core
shielded wire
Now for the final assembly. First,
attach the sockets to the front panel,
then solder short lengths of hook-up
wire to the Inject and GND terminals
on the underside of the PCB. That
done, pass these leads up through their
respective holes in the PCB, ready to
solder to the banana socket terminals.
Next, attached a short shielded
cable (for the BNC socket) to the GND
and Tracer PC stakes on the top of the
PCB. The 9V battery snap can then be
fitted. Its leads are fed through from
the battery compartment before being
looped through stress relieving holes
in the PCB and soldered to the “+” and
“–” terminals.
The next step is to fit the end panel
to the potentiometers, switch and LED
and install this into the base of the
case. The PCB is then secured using
four No.4 x 6mm self-tapping screws
that go into integral mounting pillars.
1 9.1MΩ
1 910kΩ
8 100kΩ
1 91kΩ
1 10kΩ
2 2.7kΩ
1 2.2kΩ
1 1kΩ
1 620Ω
Test Leads
Tracer In
Option 1: 1 x 1:1 oscilloscope probe
Option 2: 1 x BNC plug-to-RCA plug
lead fitted with a PC stake and 5mm
& 10mm heatshrink tubing (see text)
Option 3: 1 x BNC line plug, 1 x
RCA line plug, 1 x 500mm-length
of single core shielded audio cable,
1 x M4 nut, 1 x PC stake and 2mm,
5mm & 10mm heatshrink tubing (see
text)
Injector Out
Option 1: 1 x multimeter lead set
with accessory alligator clips
Option 2: 1 x red banana plug, 1
x black banana plug, 1 x red alligator clip, 1 x black alligator clip, 1 x
500mm length of red medium-duty
hookup wire, 1 x 500mm length of
black medium-duty hookup wire
(made into two banana plug to alligator clip leads).
Once it’s in place, complete the wiring to the banana sockets and the BNC
socket, then secure the lid to the base
using the supplied screws. You will
need to make sure that the wires do
not interfere with the banana sockets
– if they are sandwiched beneath the
banana sockets, they will prevent the
lid from fully closing.
Similarly, any wires running over
the battery compartment or over the
slider switch will prevent the case
from closing. If necessary, move the
wires out of the way using a small
screwdriver as the case is being closed.
Finally, fit the battery and the assembly is complete.
Test leads
As mentioned earlier, a 1:1 oscilloscope probe makes a suitable test lead
for the Audio Signal Injector/Tracer’s
BNC input. Alternatively, a cheaper
test probe can be made using a BNCto-RCA lead. This can be a commercial
lead but these tend to be made from
stiff large-diameter cable.
A do-it-yourself cable using a line
RCA plug, a line BNC plug and standard shielded audio cable will be much
more flexible. The connections to
siliconchip.com.au
The shield board is installed in the
case with its copper side facing down
and is secured in place using silicone
adhesive. Its copper side is connected
to the GND stake on the main PCB.
the BNC plug can be made using the
method described in the article on the
RF Demodulator Probe.
The tip of the RCA plug can be used
as the probe but note that the outer
metal earth shell must be insulated
using 10mm-diameter heatshrink tubing to prevent it making contact with
the circuit under test. In addition, a
PC stake can be soldered to the centre
pin of the RCA plug to extend it. That’s
done by first drilling a 1mm hole in the
end of the plug’s tip, then inserting the
PC stake and soldering it.
It’s a good idea to cover the RCA
plug’s centre terminal with 5mm diameter heatshrink tubing, leaving only
the PC stake “probe” exposed. This
will help prevent inadvertent shorts
when probing closely-packed circuits.
The injector signal can be fed out using a multimeter probe. Alternatively,
you can use a lead fitted with a banana
plug at one end and an alligator clip
lead at the other. A banana plug-toalligator clip lead can also be used for
the ground lead.
Testing
To check that the unit is working
correctly, connect the “Injector Out”
signal to the “Tracer In” (BNC) socket,
then plug in headphones (or earphones) and listen for the 1kHz signal.
Assuming that it’s present, check that
siliconchip.com.au
This is the view inside the completed unit. Make sure that the wiring leads to
the banana sockets aren’t squashed under them as the lid is closed (push the
leads towards the outer edge of each hole using a small screwdriver).
the level varies when the “Inject Level”
potentiometer, the “Tracer Volume”
potentiometer and the “Tracer Attenuator” switch are adjusted.
As noted above, if the tracer input is
disconnected from a circuit, the unit
will pick up hum and the 1kHz injector signal due to the tracer circuit’s
high input impedance (ie, the 1kHz
signal will be heard even when there
is no connection). The pick-up level
will depend on the capacitance of the
input cable, the attenuator setting (S2),
the injector level setting (VR1) and the
gain (Volume) setting (VR2).
Obviously, it will be at a maximum
when the attenuator is set to 1:1 and
VR1 & VR2 are at maximum but this
combination of settings would not be
used in practice. Basically, it’s just a
matter of choosing settings to suit the
job at hand and to minimise extraneous noise pick-up.
Under normal use and when connected to a circuit for testing, the
crosstalk from the injector will be
minimal and will be swamped by the
signal from the circuit under test.
Ground connections
Finally, note that when using the Audio Signal Injector/Tracer, the Ground
banana socket must be connected to the
ground of the circuit under test. This
can be done using a lead fitted with an
alligator clip as described above or by
using the earth lead on the 1:1 oscilloscope probe.
Now turn to page 68 for the optional
SC
RF Demodulator Probe.
June 2015 67
By JOHN CLARKE
Simple unit uses just a
handful of parts . . .
AM RF Demodulator
Probe For Signal Tracers
If you want to troubleshoot an AM radio with the Signal Tracer/
Injector described in this issue, you need a demodulator probe to
detect the amplitude-modulated RF signals that should be present
in the circuit being tested. This one is compact and easy to build.
Fig.1 shows the circuit details of
the RF Demodulator Probe. It uses a
fast BAT46 Schottky diode (D1) as
the detector and its output is filtered
with a 1nF capacitor to remove the
RF signal, leaving the audio modulation which can then be fed to the
Tracer.
The audio frequency response
of the probe is about -3dB down at
1.6kHz, as set by the 1nF capacitor
and associated 100kΩ resistor. Since
the RF probe is intended for use in
valve AM radios, its 100pF capacitor
is a 1kV rated ceramic type.
PROBE
TIP
100pF
Note that the probe is a passive device and requires no external power.
Construction
The RF probe is built on a PCB
coded 04106152 (45 x 11mm) – see
Fig.2. Install the two 100kΩ resistors
and the two capacitors first, followed
by the diode. Check that the diode is
correctly orientated (ie, banded end
towards the right).
The probe tip is made using a
3-way right-angle pin header. Solder
this in place and then cut the outer
two pins flush with the end of the
D1 BAT46
A
PCB, leaving just the centre pin.
PC stakes are used to terminate the
three external wiring connections.
Fit these to the PCB, then attach the
earth wire to the GND stake and the
shielded cable to the SIG and GND
terminals. The shielded wire and
the earth wire are then secured to
the PCB using two cable ties.
Once all the parts are in place,
the assembly is covered in a 55mm
length of 16mm-diameter heatshrink
tubing that’s shrunk down with a
heat-gun.
The far end of the earth lead can
RF PROBE DETAILS
K
1kV
100k
1nF
100k
EARTH
CONNECTION
SC
20 1 5
RF DEMODULATOR Probe
TO BNC
PLUG
SHIELDED CABLE
BAT46
A
K
Fig.1: the circuit uses a BAT46 Schottky diode (D1) as the detector plus a 1nF capacitor to filter out the RF signal. The
100pF 1kV input capacitor blocks DC signals, while the 100kΩ resistor sets the frequency response to -3dB at 1.6kHz.
68 Silicon Chip
siliconchip.com.au
SHIELDED CABLE
TO BNC PLUG
CABLE TIES
PROBE
TIP
1kV
BAT46
D1
SIG
GND
100k
100pF
100k
25150140
RF Probe
1nF
WIRE TO
EARTH CLIP
Fig.2: the parts layout on the small PCB. Make sure the 100pF capacitor
is rated at 1kV and take care with the orientation of Schottky diode
D1. The photo at right shows the completed PCB before the heatshink
sleeve was fitted.
THREADED FERRULE
OF BNC PLUG
SHIELDED
CABLE
ROUND EDGES OF M4 HEX NUT
WITH FILE, THEN SCREW NUT OVER
BENT-BACK SHIELD BRAID & CABLE
WIRES OF SHIELD
BRAID BENT BACK
OVER CABLE SHEATH
BNC PLUG
SLEEVE
Fig.3: this diagram
shows how the
shielded audio
cable is connected
to the BNC plug
(see text).
CENTRE PIN
COVER CENTRE CONDUCTOR WITH
HEATSHRINK TUBING
be terminated in an alligator clip
or a hook clip, while the shielded
cable goes to the BNC plug. Note
that this type of plug is designed for
use with a larger-diameter shielded
cable than the shielded audio cable
used here. However, a satisfactory
connection can be made if an M4
metal nut is used as part of the assembly hardware.
Fig.3 shows the details. The first
step is to file the six corners off the
M4 nut, so that it will fit into the
back of the BNC plug. Once that’s
done, strip the outer insulation and
the centre wire insulation as shown
in Fig.3 and solder the centre wire to
the BNC socket’s centre pin.
Next, bend the shield wires back
along the cable and twist the M4 nut
on over these wires. A short length
of 2mm-diameter heatshrink tubing
is then used to cover (and stiffen) the
centre wire before it meets the centre
pin, after which the plug sleeve can
be fitted and the threaded ferrule
tightened to secure the assembly.
Finally, the wire can secured
inside the threaded ferrule using
SC
neutral-cure silicone sealant.
Fig.3: the yellow trace in this scope grab shows a 1MHz
carrier from an old Leader signal generator, amplitude
modulated with a 400Hz audio signal. The modulation depth
is about 30%. The green trace shows the 400Hz (actually
392Hz) audio modulation from the RF probe. Note that the
recovered modulation is a somewhat distorted sinewave.
siliconchip.com.au
RF Probe Parts List
1 PCB, code 04106152, 45 x
11mm
1 BNC line plug
1 right-angle 3-way SIL header
1 500mm-length of single core
shielded wire
1 black alligator clip
1 300mm-length of black hook-up
wire
1 BAT46 Schottky diode (D1)
1 1nF MKT polyester or ceramic
capacitor
1 100pF 1kV ceramic capacitor
2 100kΩ 0.25W resistors
2 100mm cable ties
1 M4 metal nut
3 PC stakes
1 55mm-length of 15mm-diameter heatshrink tubing
1 5mm-length of 2mm-diameter
heatshrink tubing
Fig.4: the yellow trace in this scope grab shows a 1MHz
carrier from an old Marconi signal generator, amplitude
modulated with a 400Hz audio signal. The modulation
depth is about 30%. The green trace shows the 400Hz
(actually 397Hz) sinewave audio modulation from the RF
probe.
June 2015 69
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70 Silicon Chip
siliconchip.com.au
CIRCUIT NOTEBOOK
Interesting circuit ideas which we have checked but not built and tested. Contributions will be
paid for at standard rates. All submissions should include full name, address & phone number.
FRIEDLAND D780
+~~–
8V
230V
230V
AC
INPUT
W04
4N25
1N4004
T1
A
3
6
1
K
ILLUMINATED
BELL PRESS
4 x 1N4004 OR
WO4 BRIDGE
+
K
DOOR
CHIME
Wireless door
chime repeater
There are lots of situations where
the standard domestic front door
bell can’t be heard by the home’s
occupants. You might be in the garden, in the shed or you might have
a hearing problem.
This Wireless Door Chime Repeater uses a bridge rectifier connected
across an existing low-voltage door
chime and each time the doorbell
switch is pressed, the AC voltage
High-side Mosfet
switch with
optocoupler control
There are a number of high-side
Mosfet driver ICs but this circuit
takes a discrete approach, with an
optocoupler used to isolate a low
voltage (12V) switching signal from
the gate of a P-channel Mosfet.
To briefly explain, most Mosfet
switching circuits use an N-channel
Mosfet as a “low side” switch, with
the load connected between the
positive DC rail and the Mosfet’s
drain. However, that configuration
does not suit many applications
where the load needs to have one
side connected to the low voltage
. . . continued on page 72
siliconchip.com.au
6
λ
2
A
K
K
–
1
K
~A
A
R1 10k
~
ARLEC WM7A WIRELESS
PUSHBUTTON SENDER
OPTO1
4N25
C1
10 µF
+
1
5
2
–
4
63V
A
across the Door Chime solenoid
drives the bridge rectifier and the
LED inside an optocoupler to trigger
one or more wireless door chimes.
These units can be located as required or carried around by the resident if they have a hearing problem.
Capacitor C1 acts to damp the
voltage spike from the bell, buzzer
or gong solenoid’s inductance. It also
prevents phantom rings by filtering
any stray pulses or RF pickup on the
front door bell wiring.
The prototype was built around an
Arlec DC322 Series 3 Door Chime.
The wireless bell press uses a WM7A
PCB, with the press switch contacts
applying around 3V to the gate of a
small surface-mount Mosfet. The
four mounting pins of the switch
project through to the top of the PCB.
Use a multimeter to determine the
switch contacts, then solder a couple
of wires to the appropriate switch
pins and connect them to the output
transistor of the optocoupler.
Roger Forsey,
Seaholme, Vic. ($35)
Q2 SUP53P06-20
+HV IN
S
Q1
BC549C
10k
+12V IN
+
–
ON
+
12V–12V
DC–DC
CONVERTER
B
10 µF
–
D1
BAT46
25V
0V’
(HV–12V)
1k
1
2
OFF
G
E
+
A
K
OPTO1
H11L1 6
C
D
270Ω
LOAD
4
λ
5
0V
BC549C
B
BAT46
A
K
E
SUP53P06-20
D
G
C
D
S
June 2015 71
Circuit Notebook – Continued
D1 1N5817
33 µH 0.5A
A
330 µH 0.5A
K
+5V
6mA
100 µF
10 µF
100nF
2
3
ON/OFF
S1
Vin
SW
SENSE
SEL
SHDN
K
7
6
REG1
LT1301
GND
1
ILIM
4
A
220k
5V – 2.37V
3
IC2a
4.5V
BATTERY
(3xAA)
Low ohms meter
has LCD
Most digital multimeters tend to
have difficulty measuring low values
of resistance. With this in mind, this
circuit was designed to measure
resistance from 0.1Ω to 100Ω and
to displays the result on an LCD.
This involves feeding the unknown
resistance with a constant current
source and measuring the voltage
drop across it. A PIC micro then
calculates the resistance and drives
the display.
If you look at the specifications of
the PIC16F88 microprocessor, you
can see that it has an inbuilt 10-bit
analog to digital converter (ADC)
and inputs RA2 & RA3 set the voltage
range for the ADC. On this circuit
RA3 is supplied with +2.5V from an
LMZ285-2.5 reference, RA2 is connected to 0V volts and the input is
High-side Mosfet switch
. . . continued from page 71
side of a DC supply while the Mosfet
switches in the “high side”.
A good example is a motor in a
speed control circuit where its frame
needs to be connected to the negative
DC supply.
This high side switch circuit has
an SUP53P06-20 P-channel Mosfet
(Jaycar Cat. ZT-2464) connected to
a high-voltage supply and the load
72 Silicon Chip
G
D
E
1
B
Q1
BC559
IC1: OPA2336
C
120k
100nF
27k
12k
100nF
33Ω
1M
S
VR2 50Ω
8
8
470 µF
Q2
IRFU9120
VR1 500Ω
2
PGND
120Ω
VR1
LM285Z
–2.5
5
54mA
RESISTOR
UNDER
TEST
100 µF
39k
5
6
IC2b
7
4
1k
connected to RA4. If you calculate
two to the power of 10 (10-bit), the
result is 1024. If you now divide 2.5V
by 1024, the resolution of the ADC
as 2.4 millivolts per step.
If we arrange the rest of the circuit so that when 100Ω is fed with
a constant current and the voltage
at the input RA4 is 2.44V, then the
ADC result will be (2.44 ÷ 2.5) x 1024
≈ 1000. If you use the same current
and change the resistance to 50Ω the
ADC will read 500. In other words,
the value stored in memory for the
ADC result will always be 10x the
resistance.
When the resistance is below 10Ω,
the microprocessor is programmed
to increase the current through the
resistor by a factor of 10 which improves the accuracy of the measurement. From the value stored in the
ADC, the microprocessor calculates
the actual resistance value and sends
is connected between the Mosfet’s
source and the 0V line of the high
voltage supply. Note that there must
be full isolation between the inputs
and outputs of the DC-DC converter.
Optocoupler OPTO1 provides
isolation of the gate control signal
of the Mosfet. Switch S1 feeds 12V
via a 1kΩ resistor to the internal LED
of OPTO1 and this pulls the output
at pin 5 down to the 0V line of the
floating 12V DC rail.
the parallel data for display on the
LCD.
The constant current is provided
by op amp IC2a and transistor Q1
and this sets the current to 6mA (for
resistors between 10Ω and 100Ω). In
this condition, pin 13 of IC1 (RB7)
is at +5V which means that Mosfet
Q2 is off, so the constant current is
provided by 500Ω trimpot VR1 in
series with the 150Ω resistor.
As the current is 6mA and the voltage on the positive input of IC1with
respect to +5V is -2.37V (obtained
from the 2.5V zener diode and the
12kΩ and 100kΩ resistor divider)
then the value of the total resistance
should equal (2.37 ÷ 6 ) x 1000 =
395Ω. Hence trimpot VR1 should
be set at about 245Ω.
When measuring resistances below 10Ω, Mosfet Q2 turns on and
the current is now determined by
the 33Ω resistor in series with 50Ω
This pulls down the gate of Q2
via diode D1 and the 270Ω resistor
and so Q2 turns on. When OPTO1’s
pin 4 goes high, the base of transistor Q1 is pulled high, turning it on
and thus discharging the gate of Q2
for a faster turn-off.
When fed with a high-speed gate
pulse signal, the circuit will happily
run to at least 100kHz.
Gregory Freeman,
Mt Barker, SA. ($50)
siliconchip.com.au
+5V
4.7k
13
18
1k
17
15
16
3
+2.5V
2
1
K
A
Vdd
RB7
RA5/MCLR
RA1
RB6
RB5
RA0
OSC2
OSC1
IC1
PIC1 6F8 8
PIC16F88
RA4
RB4
RB3
RB2
RA3
RB1
RA2
RB0
4
12
11
8
10
6
9
16
8
15
7
14
6
13
Vss
VR2
LM285Z
–2.5
5
4
Vdd
EN
1
ABL
RS
D7
D6
16 x 2
LCD MODULE
(162B-CC-BC-3LP)
CONTRAST
D5
VO
D4
D3 D2 D1 D0 Vss R/W
7
12 11 10 9 3
5
VR3
10k
KBL
2
10 µF
LM 285 Z-2.5
BC559
K
S
IRFU9120
B
1N5817
A
1k
470Ω
14
270Ω
A K
NC
trimpot VR2, (all in parallel with
the 150Ω resistor and trimpot VR1).
We know have 6mA flowing though
VR1 and VR2 should be set at about
11Ω to provide the additional 54mA.
Op amp IC2b monitors the voltage developed across the resistor
under test. It is connected as a noninverting DC amplifier with a gain of
about 4. The OPA2336 is a rail-to-rail
CMOS op amp which is needed in
this application.
In the case of measuring a 100Ω resistor, the voltage developed across
the test resistor will be 0.6V. This is
amplified by IC2b and fed to the RA4
input of IC1. This is converted and
E
C
D
G
D
the result is displayed on the 2-line
x 16 character LCD.
The circuit is powered from an
LT1301 switchmode step-up regulator which produces +5V from three
AA alkaline cells and it will continue
to work down to +3V from the cells.
To give long battery life, a momentary
contact pushbutton is used as the
power switch. An additional 330µH
inductor is connected in series with
the regulator’s output to ensure a
low hash supply for the sensitive
ADC circuit.
When measuring low-value resistors, the resistance of the connecting
leads can give rise to an elevated
Les K
answer as they
is this m err
onth’s w
are in series
inner
of a $15
0 gift vo
ucher fro
with the resistor
m
Hare & F
orbes
being measured.
To overcome this,
you need to have two sets
of wires connecting to the resistor
being measured. One set provides
the current and the other set is connected to the input terminals (via the
27kΩ and 39kΩ resistors of IC2b) to
measure the voltage.
In the prototype, a 3mm shielded
audio cable fitted with crocodile
clips was used for connecting to the
resistor under test. At the crocodile
end, both the shield and the centre
conductor were connected to the
clip. At the other end of the first cable, the shield was connected to 0V
and the centre conductor connected
to the 39kΩ resistor.
For the second cable, the shield
was connected to the collector of Q1
and the centre conductor connected
to the 27kΩ resistor. In this way, the
shield carries the current and the
centre conductors are connected to
the voltmeter circuit.
To calibrate the unit, first adjust
the trimpots to the values stated
above. Then connect an 82Ω 0.1%
resistor and adjust trimpot VR1 so
that the display reads 82.0Ω. Do the
same with an 8.2Ω resistor only this
time adjust trimpot VR2 so that the
display reads 8.2Ω.
If the resistor is over 100Ω, then
the display will read “over range”.
The software for the micro, Low
ohms.bas, can be downloaded from
www.siliconchip.com.au
Les Kerr,
Ashby, NSW.
co n tr ib u ti on
MAY THE BEST MAN WIN!
As you can see, we pay $$$ for contributions to Circuit Notebook.
Each month the BEST contribution (at the sole discretion of the editor)
receives a $150 gift voucher from Hare&Forbes Machineryhouse.
That’s yours to spend at Hare&Forbes Machineryhouse as you see fit
- buy some tools you’ve always wanted, or put it towards that big
purchase you’ve never been able to afford!
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“Setting the standard in quality & value”
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150
$
GIFT VOUCHER
Contribute NOW and WIN!
Email your contribution now to:
editor<at>siliconchip.com.au
or post to PO Box 139, Collaroy NSW
June 2015 73
Champion
Preamp
By LEO SIMPSON
You can use this simple unit as a general-purpose stereo preamp
or as a dual-channel preamp, with a microphone for one channel
and guitar in the other. One channel can have fixed gain while
the other is variable with an on-board trimpot or external
potentiometer. Better still, it gives good performance and will
work over a wide range of supply voltages.
A
RE YOU ONE of the thousands
of readers who built our very
popular PreChamp preamplifier from
the July 1994 issue? This is still very
popular and available as a kit but it
is only a single-channel unit and its
2-transistor design is quite basic.
With the inexorable march of technology, it is now possible to do much
more, in a module which is only a
little larger and with the bonus of two
channels rather than one. Better still,
this 2-channel design draws less current than the PreChamp.
I should state at the outset that this
2-channel preamp is not a brand-new
design. It is based on the preamp section of the Champion amplifier module
which was featured in the January
2013 issue. The major feature of that
article was the tiny AN7511 monolithic
amplifier chip which can deliver up
to 7W peak power, depending on load
Main Features
• 2-channel preamplifier configurable
•
•
•
•
for different inputs
Low distortion
Low current drain: 2mA
Signal-to-noise ratio: ~80dB
Operating voltage range: 6-12V with
LP2950CZ-5.0 5V LDO regulator;
12-20V with 78L09 9V regulator
74 Silicon Chip
and supply voltage. The preamp section might have been seen almost as
an afterthought but it would be a pity
for it to have passed mostly unnoticed.
Which is partly why we have decided to devote an article just to the
preamp; that and the fact that we have
recently had a number of requests
for preamps which would be neatly
answered by this design.
So what is good about it? First, it
can use one of two dual rail-to-rail op
amps and these have the outstanding
feature of maximum output voltage
swing. So, for example, if you have a
9V supply rail, the maximum undistorted output voltage can be within
a whisker of 9V peak-to-peak; about
8.5V p-p, to be more precise. That is
much better than the old PreChamp
design and you don’t have to tweak
the input bias to obtain it.
Another advantage is that the spec
ified rail-to-rail op amps can be designed into a preamp with a very high
input impedance. This is highly
desirable if you want a preamplifier
to suit a ceramic phono cartridge or
a piezoelectric pick-up in a musical
instrument such as a violin. In both
cases, an input impedance of 5MΩ is
desirable for good bass response.
Optional electret microphone
One of the attractions of the Pre-
Champ was that you could install an
on-board electret microphone. The
only modification required was to add
a bias resistor. That feature can also
be included in this 2-channel design
and you could, in fact, have two electret microphones, although for useful
channel separation you would need
to install them both on shielded leads.
Circuit details
Let’s have a look at the circuit which
is similar to but not exactly the same as
the preamp in the January 2013 article.
Fig.1 shows the details. Both channels
are shown and the dual op amp is an
LMC6482. Since we are employing a
single DC supply rail, we need a halfsupply reference from which to bias
the inputs of both op amps.
This reference is derived from the
supply rail via a voltage divider consisting of two 10kΩ resistors bypassed
with a 100µF electrolytic capacitor. We
can use such high-value resistors for
the divider because the bias current
drawn by each input of the op amps
is a just a fraction of a picoamp. On
the other hand, we want that bypassed
half-supply to have quite a low impedance, hence the relatively large
capacitor value of 100µF.
Both op amp circuits are identical
although it is possible to have different gains in each channel, depending
siliconchip.com.au
PREAMP
POWER
+
12–20V
DC
D1 1N5819
1 A
2
–
K
REG1 78L09
1 0 0 µF
25V
10k
+9V
OUT
IN
GND
10 µF
musical instrument such as
a guitar but you can easily
increase or reduce the gain
to suit by changing the value
of R5 and you can change the
input impedance as well.
For example, if you want
to configure it for a dynamic
microphone, R2 & R3 are
changed to 100kΩ each to
give an input impedance of
50kΩ, while R5 is changed
to 100kΩ to give a gain of 101
times (41dB).
If you want to install an
electret microphone insert on
the PCB, you would install it
in place of 100pF capacitor
C101. At the same time, R101
is changed to 10kΩ and it
provides the bias current for
the electret. The other end of
the 10kΩ resistor is connected
to the positive supply rail,
from REG1.
Finally, R102 is omitted,
R103 is 220kΩ and the gain
is set to 23 (27dB) with R105
being 22kΩ.
+ 4 .5V
10k
100nF
100 µF
CON1
PREAMP
IN1
1
2
CON2
R1
100Ω
R2
2.2M
TO PIN 1 OF CON3 WHEN
ELECTRET MIC FITTED
100nF
3
2
C1
100pF
8
100Ω
1
IC1a
4
R5
56k
R3
2.2M
CUT
TRACK
100Ω
ADDED
ELECTROLYTIC
CAPACITOR
FERRITE BEAD
R4
1k
LINK TO +9V RAIL FROM REG1
WHEN ELECTRET MIC FITTED
PREAMP
IN2
10pF
100 µF
+ 4 .5V
R101
2
CON3
R102
100nF
5
6
C101
100pF
VR2*
10k
CON4
CUT
TRACK
10k
R105
R103
OPTIONAL ELECTRET MIC
INSTALLED INSTEAD OF C101
7
IC1b
PREAMP
OUT
VR1*
10k
LOG
IC1: LMC6482
1
100 µF
R104
1k
ADDED
RESISTOR
* ONLY ONE OF VR1 (16mm POT) OR
VR2 (TRIMPOT) TO BE INSTALLED
10pF
+ 4 .5V
78L09, LP2950CZ-5.0
SC
20 1 5
GND
1N5819
CHAMPION PREAMP
A
K
IN
OUT
Ceramic cartridge
Fig.1: the preamplifier circuit. It’s based around dual rail-to-rail op amp IC1. The signal
from each input is AC-coupled and biased to half supply, then amplified and re-biased to
0V DC before being fed to CON4.
on your application. For the moment
though, let’s assume that both are identical and we will just describe channel
1, based on op amp IC1a.
The input signal from CON2 passes
through a low-pass filter consisting of
a 100Ω resistor (R1) and a small ferrite
bead in series, together with a 100pF
capacitor connected to the 0V line
(C1). This is to attenuate any RF signals
that may be picked up by the input
leads. There is also a 2.2MΩ resistor
to pull the input signal to ground (R2).
If you are going to feed the preamp
with an iPod or similar player you will
need to use a much lower value of, say,
1kΩ to provide it with sufficient load
current. For the moment though, the
values we have shown on the circuit
for channel 1 are selected to suit the
pick-up in an electric guitar.
The signal is then AC-coupled via a
100nF capacitor to pin 3 of IC1a and a
2.2MΩ resistor biases the op amp’s input to the half-supply rail. This ensures
that the output waveform will swing
symmetrically within the supply rails
of dual op amp IC1. The two 2.2MΩ
siliconchip.com.au
resistors on either side of the 100nF
AC-coupling capacitor are in parallel
as far as the signal source is concerned,
setting the unit’s input impedance to
around 1.1MΩ.
IC1a buffers and amplifies the signal
from CON2 while IC1b does the same
for the signal from CON3. Gain is set at
57 times (35dB) by the 56kΩ (R5) and
1kΩ (R4) feedback resistors. The 10pF
feedback capacitor reduces the gain for
high-frequency signals, giving a little
extra stability and noise filtering.
Changing the gain
Note that this high gain suits a
Another interesting application is to use the Champion
preamp with a stereo ceramic
cartridge (don’t laugh; this
was a standard fitment on millions of
record players and many people are
dragging them out to listen to their old
record collections). Ceramic cartridges
require a high input impedance and
this is an easy option with this preamp.
Both R2 & R3 are specified at 10MΩ,
giving an input impedance of 5MΩ
which ensures good bass response.
The gain does not need to be high
though and so we can set R5 to 2.7kΩ.
This gives a gain of 3.7 (11.3dB). The
same configuration can be used for a
piezo pick-up on musical instrument
such as a violin.
So to summarise, depending on
Table 1: RC Gain Selection Values
Input
Gain R1/101 C1/101 R2/102 R3/103 R4/104 R5/105
Guitar
57
100Ω
100pF
2.2MΩ
2.2MΩ
1kΩ
56kΩ
Microphone
101
100Ω
100pF
100kΩ
100kΩ
1kΩ
100kΩ
Electret
23
10kΩ*
–
–
220kΩ
1kΩ
22kΩ
MP3
28
100Ω
100pF
1kΩ
220kΩ
1kΩ
27kΩ
Piezo Pick-up
3.7
100Ω
–
10MΩ
10MΩ
1kΩ
2.7kΩ
* Connect one end of this resistor to the +9V rail from REG1.
June 2015 75
100µF
TOP VIEW OF PCB
100nF
10pF
VR2*
10k
+
VR1*
R104 1k
10k
+
100 µF
CON2
+
100 µF
Out
CON4
CUT
TRACKS
+
10pF
10 µF Power
100 µF
25V
+
+
10k
CON1
100nF
R5
+
C1
IN 2 100pF
R2
IN 1
R3
100Ω
100nF
IC1
BEAD
R1
R4 1k
CON3
R102
R103
UNDERSIDE OF PCB
+
01109121
R105
+ 100pF
BEAD
LMC6482
C101*
100Ω
R101 100Ω
−
REG1
78L09 D1
+
5819
* OPTIONAL ELECTRET
LINK WHEN ELECTRET MIC
FITTED INSTEAD OF C1
* FIT EITHER VR1 OR VR2,
NOT BOTH
INSTALLED INSTEAD
OF C101
Fig.2: follow this layout diagram to assemble the PCB. It’s best to cut the tracks
first and then check with a continuity meter before fitting the parts.
Table 2: Resistor Colour Codes
o
o
o
o
o
o
o
o
o
o
o
Value
10MΩ
2.2MΩ
220kΩ
100kΩ
56kΩ
27kΩ
10kΩ
2.7kΩ
1kΩ
100Ω
4-Band Code (1%)
brown black blue brown
red red green brown
red red yellow brown
brown black yellow brown
green blue orange brown
red violet orange brown
brown black orange brown
red violet red brown
brown black red brown
brown black brown brown
what type of source you are using and
the gain required, you can easily obtain
the required input impedance and
gain. Table 1 shows the values to use.
Two outputs
In the original Champion preamplifier, the outputs of the two op amp
stages are mixed using a pair of resistors and then AC-coupled to potentiometer VR1 or VR2, depending on
which is installed. In our application,
we want two separate outputs and so if
an output level control is to be used, it
can only affect one channel. As shown
on the circuit of Fig.1, the output of
IC1b connects to VR1 (or VR2) via a
100Ω resistor and 100µF DC blocking
capacitor. The wiper of VR1 then connects to one terminal on CON4.
The output of IC1a is also fed via a
100Ω resistor with a second blocking
capacitor and bias resistor added under the board. This output goes to the
other terminal on CON4. Note that two
track cuts on the PCB need to be made,
in order to give this independent two
channel operation.
IC1 is powered via a 78L09 lowpower 3-terminal 9V regulator, assuming you are using a DC plugpack with
76 Silicon Chip
5-Band Code (1%)
brown black black green brown
red red black yellow brown
red red black orange brown
brown black black orange brown
green blue black red brown
red violet black red brown
brown black black red brown
red violet black brown brown
brown black black brown brown
brown black black black brown
Table 3: Capacitor Codes
Value
100nF
100pF
10pF
µF Value
0.1µF
NA
NA
IEC Code EIA Code
100n
104
100p
101
10p
10
an output of 12V or more (up to 20V
DC). This regulator is fed from CON1
via Schottky diode D1 which protects
against reversed supply polarity.
Note that if you intend using a
9V battery for this project, you may
want to employ the LP2950CZ-5.0 5V
regulator. No other modifications are
required if you make this change but
the preamplifier will inevitably have
a reduced output voltage swing and
therefore a reduced overload margin
for strong input signals.
Construction
You will be using the Champion
PCB for this project (code 01109121)
and you will need to cut off the section
for the AN7511 audio amplifier. Don’t
discard it – it’s a handy little amplifier module in its own right and the
AN7511 amplifier chip is quite cheap.
Parts List
1 PCB, code 01109121, 57 x
41mm (see text)
1 PCB-mount electret microphone
insert (Jaycar Cat. AM4011)
(optional; see text)
1 10kΩ log PCB-mount 16mm
potentiometer (VR1) OR
1 10kΩ mini horizontal trimpot
(VR2)
2 ferrite beads, Jaycar LF1250
4 mini 2-way terminal blocks
(CON1-CON4) (omit one if electret is installed)
1 8-pin DIL socket
4 M3 x 10mm tapped Nylon
spacers
4 M3 x 6mm machine screws
1 short length hookup wire (60mm)
Semiconductors
1 LMC6482 or LMC6032 dual op
amp (IC1) (eg, Jaycar ZL3482)
1 78L09 or LP2950CZ-5.0 5V LDO
regulator (REG1) (eg, Jaycar
ZV1645) – see text
1 1N5819 Schottky diode (D1)
Capacitors
1 100µF 25V electrolytic
3 100µF 16V electrolytic
1 10µF 16V electrolytic
3 100nF MMC or MKT
2 100pF ceramic (omit one if electret is installed)
2 10pF ceramic
Resistors (0.25W, 1%)
3 10kΩ
2 100Ω
See Table 1 for R1-R5
Note: Jaycar will be selling a kit
of parts for this project – Cat. KC5531.
The remaining preamplifier PCB
measures just 57 x 41mm. It has provision for mounting pillars at its four
corners and four 2-way connector
blocks. One of those blocks is used as
the terminals for the two preamplifier
outputs.
Since there are changes to the component layout, this means that you will
have to follow the parts layout of Fig.2
and ignore most of the resistor values
shown on the screen-printed layout on
the PCB itself. You also need to cut the
copper tracks of the PCB in two places
as shown on Fig.2.
Having cut the tracks, start the assembly by installing the resistors.
siliconchip.com.au
+3
11/05/15 12:00:11
Pre-champion Frequency Response
1.0
+2
11/05/15 12:15:43
Pre-champion THD+N vs Frequency
Input signal = 50mV RMS, gain ≈ 27, bandwidth = 80kHz
0.5
Total Harmonic Distortion + Noise (%)
+1
Amplitude Variation (dBr)
0
-1
-2
-3
-4
-5
-6
-7
0.2
0.1
0.05
LMC6482
0.02
LMC6032
0.01
.005
-8
.002
-9
-10
10
20
50
100
200
500
1k
2k
5k
10k
20k
50k 100k
.001
20
50
100
200
Frequency (Hz)
Fig.3: frequency response is within +0,-0.5dB between
30Hz and 20kHz with -3dB points around 8Hz and 55kHz.
It’s less than 1dB down at 20Hz.
500
1k
2k
5k
10k
20k
Frequency (Hz)
Fig.4: the LMC6032 has about half the noise of the LMC
6482. The LMC6032 requires slightly more operating
current than the LMC6482 but still under 1mA.
These two larger-than-life-size views show the
completed PCB assembly. Note the wire link on the
back of the PCB when an electret mic is used.
You will need to refer to Table 1 for
the values for R1-R5 and R101-R105.
Table 2 shows the colour codes but it
is good idea to check each value with
a multimeter before fitting it. A ferrite
bead should be slipped over one leg of
each 100Ω input resistor, if fitted (ie,
R1 & R101).
Follow with diode D1 and then fit
the IC socket with its pin 1 notch orientated as shown. Next, fit the 78L09
or LP2950CZ-5.0 regulator, REG1. Follow with the ceramic and monolithic
capacitors.
The 2-way terminal blocks are next,
each installed with its wire entry holes
facing outwards. Note that CON3 is not
installed if you have fitted an electret
microphone insert for channel 2.
The next step is to decide whether to
fit potentiometer VR1 or trimpot VR2.
It will only control the output signal
level from one channel and you may
decide to link it out. You can then fit
all the electrolytic capacitors. In each
siliconchip.com.au
case, the longer lead goes into the hole
marked with a “+” sign.
Once those parts are in, fit the M3
x 10mm tapped spacers to the corner
mounting positions using M3 x 6mm
machine screws.
If you are installing an electret, wire
a 10kΩ resistor in the position for
R101 and connect the end adjacent to
CON3 to the output of the 3-terminal
regulator. We show this with a dotted
red line on Fig.2. In addition, R102
and C101 are omitted.
If you are going to use only one channel of the preamplifier, it’s a good idea
to short the unused channel’s input
to 0V by using a wire link for resistor
R1 (or R101) and by shorting the two
terminals of CON2 (or CON3).
When you have carefully checked
your assembly and soldering against
the circuit of Fig.1, Table 1 and the
overlay diagram of Fig.2, you are ready
to apply power. Check that the output
of REG1 is 9V (or close to it) if a 78L09
has been fitted. If an LP2950CZ-5.0 has
been fitted, REG1’s output should be
close to 5V.
Next, turn off the power, insert the
op amp (carefully), power back on and
then check the DC voltage at pins 1 &
7. In each case, they should be sitting
at half supply; 4.5V for a 9V supply
and 2.5V for a 5V supply.
Performance
Figs.3 & 4 show the frequency response and total harmonic distortion
curves of the preamplifier. Note that of
the two op amps we’ve specified, the
LMC6032 gives the best performance
but it isn’t as easy to get as the more
common LMC6482.
To achieve a THD+N this low, the
preamp will need to be installed in an
earthed metal box. Otherwise, hum
and RF pick-up will reduce the signalto-noise ratio and consequently the
total harmonic distortion perform
SC
ance.
June 2015 77
SPIKE:
improved software
for the Signal Hound
By JIM ROWE
When we reviewed the Signal Hound USB-SA44B mini
spectrum analyser in the October 2014 issue of SILICON CHIP, we were
very impressed with the performance of both the hardware and its accompanying
software. Now Signal Hound has come up with a greatly enhanced software pack
age to go with the USB-SA44B and their other instruments.
I
N OUR ORIGINAL review of the
USB-SA44B spectrum analyser, we
were particularly impressed with the
analyser hardware itself. Inside its
compact 77 x 27 x 167mm aluminium
case there is an advanced narrow-band
SDR receiving system tuning over
the range from 1Hz to 4.4GHz and
delivering a level of performance that
compares very favourably with high-
end self-contained spectrum analysers
– but at a fraction of their price.
We were also impressed with its
software package which controls the
USB-SA44B hardware box (and the optional USB-TG44A tracking generator)
from your PC as well as accepting, processing and analysing the output data
stream from it to produce the analyser’s
output display and measurements.
Fig.1: a full-screen grab of Spike in “real time” mode scanning at a centre frequency of 1090MHz, showing Persistence on the spectrum plot (lower centre), with
a 2D spectrogram above it.
78 Silicon Chip
The software did have a few rough
edges but we judged them to be fairly
minor and not significant, considering
the excellent performance of the USBSA44B hardware. But early this year
Signal Hound released a greatly enhanced version of their software package, renamed “Spike”. And in the last
three months or so they’ve released a
number of upgraded versions of Spike.
We’re reviewing the latest version
at the time of writing: Spike 3.06.
This is now being provided on the
CD accompanying the USB-SA44B
and other analysers purchased new.
Existing users can download it at no
charge from Signal Hound’s website at
www.signalhound.com/spike
It comes as a zip file which includes
its matching USB drivers. A PDF of
the User Manual for the new software
can also be downloaded from the same
website.
Spike 3.06 is compatible not just
with the USB-SA44B but also with
the rest of the Signal Hound products,
including the USB-TG44A tracking
generator. There are two versions,
compatible with the 32-bit or 64-bit
versions of either Windows 7, 8 or 8.1.
Note that although the Spike softsiliconchip.com.au
Fig.2: a spectrum plot showing the Sydney DRMT DAB+
signal block centred on 204.5MHz in channel 9A, captured
using Spike 3.06 and saved as a JPEG file.
Fig.3: another plot centred on 92.9MHz, showing the Sydney ABCFM signal spectrum (bottom) with a 2D spectrogram above it. Spike again saved it as a JPEG file.
ware can be downloaded and installed
at no charge, it will only work with
Signal Hound devices like the USBSA44B. When you start up the software
it automatically searches the PC’s USB
ports to see if one or more of the devices is connected. When it finds one,
it displays the device’s serial number
and other information (like internal
temperature and firmware revision) at
bottom right on its main display window; otherwise it refuses to proceed.
What’s new?
The first thing you notice when you
fire up Spike (in my case, with a USBSA44B) is that the user interface window has been completely revamped.
The main display graticule is now
centred on the screen, with control
panel menus running down either
side. It’s less crowded than before,
having been proportioned to suit the
16x9 wide-screen aspect ratio used on
most modern laptops and PC monitors.
As before, the main functions, settings and facilities are selected using
a menu bar and toolbar running along
the top. The control panel menus on
the left side then allow you to set the
Measurement trace and marker parameters, any offsets that may be required
and settings for Channel Power and
Occupied Bandwidth measurements.
The menus on the right side control
panel allow easy setting of all sweep
parameters: Frequency (Centre, Span,
Start, Stop and Step, plus the ability
to set the analyser for either Full Span
or Zero Span [more about this later]);
siliconchip.com.au
Fig.4: this full-screen grab shows Spike 3.06 in real-time scanning mode, centred
at 1090MHz (the frequency used by commercial aircraft for ADSB). The 2-D
spectrogram is shown above the spectrum plot itself.
Amplitude (Reference Level and Graticule Divisions, plus the ability to select
either manual or automatic internal
gain, attenuation and preamp enabling); Bandwidth (RBW and VBW);
and finally Acquisition options such
as Video units, Detector mode and
Sweep Time.
This is not Spike’s only display
graticule or control menu panel, as
will become clear shortly. So Spike’s
initial window is much snazzier than
that of the original Signal Hound software. But that’s only the start of its new
features and capabilities, because
the new software can now take full
advantage of the capabilities of Signal
Hound’s analyser hardware – including those of the USB-SA44B.
For example, you can now select
either of two different types of spectrogram to accompany the analyser’s
main amplitude vs frequency display:
a 2D spectrogram which gives the moving “waterfall” display or a 3D spectrogram which gives a series of sweep
displays receding into the distance.
These can both be helpful when you’re
trying to look for significant events.
Another nice new feature applying
to the main graticule display is persistence. When you enable this feature,
the current signal trace is accompanied
by a “community” of earlier traces, in
colours representing their time prior
to the current trace.
It’s a bit like having a fixed spectrogram displayed directly behind the
June 2015 79
Fig.5: another screen grab showing Spike in real-time scanning mode, centred at
1090MHz, this time with a 3-D spectrogram shown above the spectrum plot.
Fig.6: this screen grab shows Spike 3.06 in “zero span” mode – another of its
exciting new features, designed to facilitate modulation analysis. It shows the
actual spectrum plot at lower left, with the modulation plotted against time at
upper left and the I/Q IF output stream at lower centre. A summary of the signal
and modulation data is shown at upper centre.
trace itself, in the main graticule.
There’s another new feature that’s
even more impressive: Spike now
provides a real-time spectrum analysis
mode, to allow capturing occasional
short-term events which can easily
be missed in normal sweep analysis
if they occur during the “dead time”
between sweeps.
In real-time analysis mode, Spike
takes advantage of the ability of Spectrum Hound’s analyser hardware to
stream its full IF bandwidth back to
the PC (via the USB cable) continuously, with no time gaps. So by limiting the sweep span to the maximum
instantaneous bandwidth, Spike is
now able to process and analyse every
spectrum sample in real time.
Incidentally, the spectrogram and
80 Silicon Chip
persistence features can be applied
in real-time mode just as easily as
in sweep mode. If this isn’t enough,
there’s now a zero-span analysis mode
too. This might sound a bit strange but
it’s really quite easy to understand.
In zero span mode, Spike directs the
analyser to stay locked to the centre
frequency you’ve set, while it again
streams the full IF bandwidth back
to the PC.
This allows Spike to demodulate
any AM, FM or PM modulation
which may be present on a signal
at that centre frequency. As a result,
when Spike is in zero-span mode, the
screen changes dramatically, with the
RF amplitude vs frequency spectrum
graticule reduced in size and moved
to the lower left, while the modulation
is displayed plotted against time in a
new graticule across the top.
In addition, the I and Q components of the analyser’s IF data stream
are displayed in a third graticule at
lower right, alongside the amplitude
vs frequency plot. Then if you enable
Spike’s AM/FM modulation analysis
feature, the upper modulation vs time
graticule contracts to the left, and quite
a bit of modulation analysis data is
displayed in the top right quadrant.
You’re shown a continuously updated summary of RMS, Peak+ and
Peak- modulation percentages, plus
the modulation frequency and RF centre frequency, together with the SINAD
(dB) and THD (%) figures.
Other features
There are other noteworthy features
as well, including:
(1) The ability to call up an Audio
Player function, to listen to any AM or
FM modulation of the centre frequency
signal via the PC’s speakers;
(2) The ability to call up a Measuring
Receiver function, to display various
key parameters of the centre frequency
signal;
(3) The ability to record the data from
an analyser session as a file on the PC,
and also to replay a recorded file for
further analysis;
(4) In zero-span mode, there’s also
the ability to save a short duration
I/Q capture, either as a binary file or
in a text-based format such as a CSV
(comma separated variable) file;
(5) The ability to plot phase noise and
(6) If you add a USB-TG44A Tracking
Generator to your set-up, the software
can be easily set up to perform scalar
network analysis.
In short, Signal Hound’s new Spike
3.06 software really expands the
measurement applications of their
USB-based spectrum analysers (like
the USB-SA44B) dramatically, as well
as taking full advantage of the hithertohidden performance features of the
analyser hardware.
The new User Manual for Spike is
also a significant improvement on the
original manual, which was already
pretty good.
In Australia and New Zealand,
Signal Hound products like the
USB-SA44B and the USB-TG44A are
distributed by Silvertone Electronics,
now based in Wagga Wagga, NSW.
You’ll find their website: www.silverSC
tone.com.au
siliconchip.com.au
Final part of our quality Weather Station based on
System designed
by Armindo Caneira*
Built and written
by Trevor Robinson
*www.meteocercal.info
The Wireless
Display Unit
In the last part, we built the RX unit and configured Cumulus to collect,
record and display your weather data. Now we are going to complete the
Weather Station by building the handy little Wireless Display unit (WDU).
T
he Wireless Display unit actually evolved from the
RX unit (which, incidentally, can also be used as a
WDU with some minor mods).
It receives wireless data on a 433MHz link from the RX
unit (see part 3), which in turn has received data from the
outside weather sensors via the TX unit (see part 2).
It also sends data from its own DHT22 temperature and
humidity sensor. The main differences between the two is
the barometer sensor and the run/program pullup switching
has been omitted.
And of course, it has its own
firmware file.
Beside having a display
screen, it only has one
push-button switch (the Display Mode switch) and a LED.
The LED blinks when data is received over the 433MHz link.
The WDU is powered through its Mini-B USB connector,
so you will need a 5V DC power pack with a mini-B USB
connetor or a Mini-B USB cable to connect it to a suitable
power supply like a USB phone charger.
Once again, like the RX unit, you have the option of one
of the following five different displays:
TFT – ILI9341 2.4” or 2.2” (320x240) or the ST7735 1.8”
(160x128)
Alphanumeric LCD: 20x4, or 16x2 with I2C module
Constructing the Wireless Display Unit
The WDU PCB purchased from Meteocercal will al-
A completed WD
unit with a 2.4”
TFT display
siliconchip.com.au
June 2015 81
(Above): reverse side of the WD PCB; the “top” side at right has the Arduino Nano and
433MHz modules fitted.
ready have the surface mount components soldered on, as
shown above (there is also an SMD on the opposite side).
These can be a bit tricky without the correct tools.
Once again, like all electronic kitset projects, it’s easiest
to install and solder in the smallest components first: the
resistors and capacitors.
Next install the LED, observing the polarity, followed by
the header and antenna connectors.
Like last month, it’s best to install the Nano using a
suitable socket. But if you are soldering the Nano directly
to the PCB, it’s good practice (as with all heat sensitive
components) to stagger the soldering of the pins to help
avoid localisation of heat build up.
Finally install the BX-RM06 ASK OOK RF receiver module vertically on the WDU board. Ensure that the component
side of this board goes to the outside of the WDU board
pin – its easy to install this component back-to-front if care
isn’t taken. Not only will it not work, it will quite likely be
damaged (and it’s a pain to desolder!).
The WDU board is now complete but before moving on,
double check your work, looking for solder bridges (especially between module and header pins) and cold solder
joints. A jeweller’s loupe or magnifying lamp are great tools
for getting a good close-up view.
the Dupont female to female wires to make
life easy. The backlight jumper needs to
remain in place, but you may need to
tweak the contrast potentiometer.
LCD
Connecting the display screen
Both of these are dependent on what sort of case you get.
The momentary action pushbutton switch should be
connected by soldering wire to the contacts and then the
other end to the contacts of the header connector plug. The
LED can be soldered into its position on the PCB, though it
would be better to use a suitable length of cable to connect
it to the PCB from somewhere visible on the case. The push
button changes the display mode as per the table below:
Much of the following information is repeated from last
month’s (Part 3 – The Receiver) issue because the Wireless
Display Unit and Receiver Unit share a common heritage
and indeed, most parts
TFT pin assignment
are interchangeable.
TFT display
Use nine of the Dupont female to female
wires to connect PCB
pin headers to TFT pin
headers.
Currently the SD card
and touch overlay are
unused.
Alphanumeric LCD
PCB TFT Display
2.4” TFT –
ILI9341 320x240
SCLK SCLK
MOSI
SDA
CS CS
RST
RESET
SDI(MOSI)
PCB LCD
GND
GND
This is the same as what we did for
5V
the RX unit. We’ll cover it briefly again, 5V
just in case your dog ate your homework SDA
SDA
last article.
Solder four header contact pins to SCL SCL
one end of whatever
length of cable you
DHT22 Temp. Sensor
require. The maxiPCB Schematic Pin DHT 22 pins
mum length this cable
can be is five metres. GND
1 (GND)
3 OR 4
Solder and heatshrink
2 (D6)
2
the other end to the DAT
four legs of the DHT22 5V
3 (5V)
1
sensor.
Ensure the pin assignment matches the table above.
Push button (display mode switch) and
LED (data received indicator)
SCK
Display Mode Switching
LCD
TFT
CS
Short press
Nothing
Toggles the Display off/on
RESET
Long press
Nothing
Toggles the big font size screen
DC A0
D/C
5V VCC
VCC
GND GND
GND
The LCD connection
LED
process is simpler as it LED+ LED+
only uses four wires. LED-
LED-
No connection
You can also use four of
needed
82 Silicon Chip
Connecting the DHT22
temperature sensor
Pinouts
Button Action
Double press Toggles the information screen
The information screen shows the firmware version, TX
unit voltage and case temp from the TMP36 sensor.
Programming the WeatherDuino Pro2 Nano
Since you are now an old hand at programming Arduinos,
we shouldn’t have to go into too much detail here. If you
siliconchip.com.au
Another view of
the completed
WDU PCB, this time
showing the method of
mounting the 433MHz
wireless link. Take care
with this – with four pins
at each end it’s not difficult
to solder it in the wrong way
. . . but rather more difficult to
unsolder it and fix your mistake!
need a refresher, part two had an in-depth guide to setting
up the IDE and part three covered reading and altering of
the WeatherDuino code to suit that application; maybe
read those again.
Acquire the required firmware
Download the required firmware file from here: www.
meteocercal.info/forum/Thread-WeatherDuino-Pro2-WDSoftware-Latest-Release
Save the file to wherever, then extract the contents into
your Arduino sketch folder which should be in the \users\
your_username\Documents\Arduino folder. Click “OK”
on any merge or overwrite dialog boxes.
Now go into that folder and double click the folder
WeatherDuino_WD_vxxx_bxxx (the “x”s change by release
version). Then in that folder there should be a file called
WeatherDuino_WD_vxxx_bxxx.ino – double click that to
open it in the Arduino IDE.
Configuring the code
Now we need to tweak a few lines to suit our WDU setup.
Scroll down to around line 44.
We need to start by changing the code to suit our display
type, so pick your display type number from the comment
section: 0= TFT 160x128 ST7735, 1= TFT 320x240 ILI9341,
4= 20x4 LCD, 5= 16x2 LCD
Say your have the big LCD display, you would change
the line to read this:
#define DisplayType 4 // 0= TFT 160x128 ST7735, 1=
TFT 320x240 ILI9341, 4= 20x4 LCD, 5= 16x2 LCD
The big TFT display is set to the default so you would
just leave that line as is.
Next is the Backlight timeout:
byte BackLight_Timeout = 0; // Timeout for TFT backlight
in minutes (1 to 255). 0= Always ON
siliconchip.com.au
You have the option of having it on continuously (though
a short button press turns it off) or setting the timer to turn it
off automatically some time after the last button press. Your
choice. If you want to just manually turn off the backlight
then just leave the default setting.
Next is the Temperature sensor type. Since we when
with the good old DHT22 you can left this line alone also.
The next line you also leave at the default setting of 1
#define Board_Type 1 // 0= Standard Boards, 1= Extended version Wireless Display Boards
Pretty simple configuration on this unit isn’t it?
Save it with a filename that reflects your setup so if
you wish to tweak/change it in the future, you will know
what it is.
Compile and upload it to the Nano by pressing the right
arrow in the Arduino IDE. After a short period of time the
WeatherDuino Pro2 Wireless Display unit should reboot
and a little while later the inside temperature should be
displayed and after a little more time the outside data
should display.
If the IDE produces errors its usually one of two things:
1: File too big. Your are not running the Arduino IDE
version 1.5.8 or greater.
2: The library files are not where the IDE is expecting
them. Double check they are in the sketch folder or manually import them in the IDE (Sketch/Import Library).
That’s all folks!
We hope you enjoyed creating this project and find the
data this weather station creates is more reliable and accurate than your previous station may have produced, or
even the weatherman on the radio.
We certainly did!
When you get you weather station online, please leave a
post on the Meteocercal forum so you can have your station
added to the WeatherDuino user map here:
www.meteocercal.info/forum/misc.php?page=
WeatherDuino_Users_Map
SC
June 2015 83
Vintage Radio
By Ian Batty
The Philips model 198
transistor radio
Philips’ first Australian-made transistor set
Housed in an attractive leatherette case,
the model 198 was Philips’ first Australianmade transistor set. It was a 7-transistor
design and both it and the later model 199
offered excellent performance.
B
EGINNING IN Eindhoven in 1891
and founded by Gerard Philips and
his father Frederik, Philips became
one of the world’s largest technology
companies but today it concentrates on
lighting and healthcare. The company
began manufacturing in Australia in
1931 but produced only two models
before temporarily halting production
and then resuming in 1934.
Philips then quickly grew to become
one of Australia’s largest electronics
manufacturers, with radios sold under
84 Silicon Chip
the Briton, Mullard and Fleetwood
brand names. TV receiver production
subsequently started in 1956 and
continued until the 1980s. In addition, Philips manufactured valves, TV
picture tubes and transistors, including the famous OC44/45 and OC70/
71/72/74 series that many of us bought
to build our first transistor sets.
Design highlights
Described in Vintage Radio for April
2015, Australia’s first transistor radio,
the AWA 897P, was released in 1957.
This was followed just a year later by
Philips with their model 198. Like the
897P, this was another 7-transistor design and the case used by Philips was
modelled on a previous valve version,
the compact AC/battery model 196.
AWA’s engineers used three audio
stages in the 897P, based on four
transistors and three transformers. By
contrast, Philips opted for a design
that was to become standard, with
just three transistors and two transformers used for the audio amplifier.
Like AWA, Philips paid attention to
Australian conditions, by employing
a thermistor-stabilised output stage.
They also added adjustable output
stage bias, as described below.
The Philips 198 was more compact than the AWA 897P and it looks
somewhat like a small cosmetics case.
But don’t let its “domestic” appearance fool you – it really is a very good
radio. The accompanying photos show
the set’s controls which are, from left
to right: Volume, Off, Treble/On and
Bass/On along the top and, on the
front panel, a tuning control with
integral dial.
Philips 198 chassis details
Like Bush’s TR82C and AWA’s 897P,
the Philips 198 uses a pressed-andpunched metal chassis. Its successor
(the 199) is similar but with sufficient
differences to warrant a separate circuit diagram (the major differences are
noted in the text).
The 198 has five of its transistors
installed in chassis-mounted rubber
grommets, with the leads wired to adjacent solder tags. By contrast, the two
output transistors are held in heatsink
clips which are screw-mounted on the
underside of the chassis.
Unlike the AWA set, the chassis sits
horizontally inside the case, allowing
some access to the underside where
most of the components are mounted
on tagstrips. The IF transformers and
the LO coil, however, are mounted versiliconchip.com.au
Fig.1: the circuit details of the Philips 198. TR1 is the converter stage, while TR2 & TR3 are the IF amplifier stages. D2
is the detector and this feeds buffer stage TR4 which in turn drives an audio amplifier based on TR5-TR7.
tically, so that the chassis still needs
to be removed for any detailed work,
including alignment.
The case itself is made from leatherette-covered “composite” material
(cardboard), while the front dial at
top-right turns easily with a direct
drive. To the left of the dial is a large
speaker grille. Power is controlled by
pushbutton switches, so the volume
pot only controls the volume. Because
it doesn’t also function as an on/off
switch, the volume pot doesn’t have
to be turned down to or up from zero
each time the set is turned off or on,
thereby extending the pot’s life.
Circuit details
Fig.1 shows the circuit details of the
Philips 198. Transistor TR1 is the converter stage and this operates as an autodyne oscillator with collector-emitter
feedback. AGC is not applied to this
stage, so TR1 operates with fixed bias.
As shown, TR1’s bottom divider resistor (R2) and its bypass (C4) are connected between the “cold” (bottom)
end of the ferrite rod’s two windings
(tuned and base) and ground. This
means that the bottom of the antenna
windings are at base bias voltage,
thereby providing a handy test point.
By contrast, the later 199 model connects both antenna windings directly
siliconchip.com.au
to ground, with the bottom of the base
bias circuit going to the top of the base
winding.
The base-emitter voltage is only
50mV, since converters must operate
close to Class B conditions to give the
non-linear “modulating” effect needed
for frequency conversion.
Because the tuning gang uses identical sections, padder capacitor C9 is
included to modify the capacitance
range of the oscillator section so that
the local oscillator tunes from about
990-2060kHz. The only unusual feature is that the oscillator coil’s secondary is held at the converter’s collector
voltage. While this eliminates any potential difference between primary and
secondary, it’s not common practice.
Converter TR1 feeds the first IF
stage (TR2) via IF transformer L3/L4
which has tuned and tapped primary
and secondary windings. TR2 is gaincontrolled by the AGC system and due
to the high feedback capacitance of
alloyed-junction transistors, this stage
is neutralised by feedback via C13 from
the second IF transformer’s untuned
(and untapped) secondary. By contrast,
in the 199 model, this feedback is derived from an overwind on the second
IF transformer’s primary. In addition,
the second IF transformer has a tuned
and tapped secondary.
The second IF stage is based on
TR3 and runs with fixed bias. It’s also
neutralised, via C19, and both the 198
and 199 models derive feedback from
the third IF transformer’s secondary.
The third IF transformer uses a
tuned, tapped primary and a lowimpedance, untuned secondary to feed
demodulator diode D2.
AGC circuit
Depending on the strength of the
incoming RF (and IF) signal, diode D2
provides a negative DC output to the
base of TR4, the first audio/AGC stage
transistor which is connected as an
emitter follower to buffer the detector.
Stronger IF signals will therefore
cause TR4’s emitter current to increase
but it does not amplify the resultant audio, merely passing it to the following
volume control potentiometer (R20).
However, the DC signal from TR4’s
emitter is then filtered by capacitor
C14, so that the resultant DC voltage is more or less proportional to
the IF signal strength. This DC voltage is applied to the emitter of TR2
and if this voltage increases, TR2’s
gain will tend to be reduced. As a
result, changes in signal strength
are counteracted and the set’s output
remains substantially constant for varying signal strengths.
June 2015 85
The model 198 is built on a metal chassis, with point-to-point wiring. Five of its transistors are installed in chassismounted rubber grommets while the two output transistors are held in heatsink clips which are screw-mounted on
the underside.
As well as AGC, the set also includes
an “overload diode”, better described
as an “AGC extender”. Simply controlling one stage (such as TR2) only
provides a limited range of control. In
this set, the stage gain is some 30dB
and thus simple AGC can only counteract about this range of input signal.
After that, the audio output begins to
rise noticeably or the second IF stage
goes into overload.
To prevent this, auxiliary AGC diode
D1 is connected between the primary
of the first IF transformer (L3) and the
collector supply to TR2 at the junction
of R7 and C16. This latter junction sits
at about -5.4V DC but is effectively at
signal ground due to C15. By contrast,
D1’s anode at L3’s primary sits at about
-6.2V DC and is at IF signal level. It’s
also connected (via L5) to converter
TR1’s collector.
With no signal, D1 has around 0.8V
of reverse bias. As TR2’s collector current falls with increasing signal, its
collector voltage (developed across R7)
rises. This pulls D1’s cathode towards
the supply voltage and (importantly)
reduces its reverse bias. As TR2’s
collector current falls further with
increasing signal strength, D1 eventually begins to conduct and damps the
IF signal at TR1’s collector, thereby
preventing it from increasing.
The result is that the model 198 has
86 Silicon Chip
effective AGC and provides consistent
audio output levels over a wide range
of signal strengths.
R32-C32, with the 100nF capacitor
increased in value for the 199.
Audio stages
The push-pull Class B output
stage is based on TR6 & TR7 and has
thermistor-compensated bias (R29).
This bias can be adjusted using R27.
The model 198 also has a shared 5Ω
emitter resistor (R31) but this was
removed for the 199. At 5.5mA, the
bias current is a little higher than in
most other sets but I found that I was
able to set it to almost zero with no
noticeable increase in crossover distortion. The alignment guide, by the way,
recommends running the set for three
minutes prior to checking or adjusting
the output stage bias.
In the model 198, audio stage feedback is applied from TR6’s collector
to TR5’s base via two paths. First,
there is a permanent feedback path via
R22-C27 (the 199 uses a single 220kΩ
feedback resistor and takes the feedback from the speaker terminal). And
second, Bass switch S1/S2 switches
C29 and R30 across the feedback path
to apply extra treble roll-off (the 199
uses slightly different values here). In
operation, this brings the upper -3dB
point down to just 2kHz (the model 199
also derives this “top-cut” feedback
from TR6’s collector).
S3/S4 (Treble) switches in C33 to
The audio stages begin unconventionally with the emitter follower/
buffer stage based on TR4. It’s more
usual to see a common-emitter stage
here but given the AGC design (which
feeds some current through NTC
thermistor R16 in order to operate), it
makes sense. In operation, TR4’s bias
is temperature-stabilised by R16, presumably to prevent TR4’s AGC action
from being disturbed by high or low
ambient temperatures.
Following TR4, the signal is fed to
the remaining audio stages via volume
control pot R20. Its circuit configuration is also unconventional: its “hot”
end connects to TR4’s emitter and
its “cold” end goes to TR5’s emitter,
which produces about 0.7V DC across
the pot. However, because TR5’s emitter is at AC (signal) ground, R20 works
just fine as a volume control. The
peculiarity is that there is standing
DC across the pot, which is usually a
recipe for noisy operation.
Audio driver TR5 is a conventional
transformer-coupled stage. No treble
roll-off is applied here but was added
in the 199 model. It is, however,
applied in the output stage using
Push-pull output stage
siliconchip.com.au
This is the under-chassis view of the model 198. The set was still in working order and no parts had to be replaced,
although the set did require alignment adjustments in order to optimise its performance.
provide extra bypassing for the demodulator (this is absent on the 199). Like
the Bass switch, it also turns the set on
via its second set of contacts.
By the way, the circuit shown here
is a redrawn version, since the original
circuit isn’t all that clear (at least as
found online). The original component
numbering has been preserved.
Restoration
The set shown here was quite tatty
when I took it out of storage. On the
outside, its leatherette-covered composite case and tuning dial were dirty
and the metalwork was tarnished and
corroded. In addition, the Philips
badge on top (just behind the switch
well) and the “All Transistor” badge
inside the escutcheon were both bent.
It’s a common problem and of the four
198/199 sets I have, this one was the
best preserved.
I attacked the leatherette case first
using a microfibre pad but soon noticed that some of the fawn colour was
transferring to the pad. I’d also had a
similar experience of colour lifting
with the Bush TR82C, so I’ll use these
microfibre pads with caution in future.
In the end, the case was cleaned
using spray cleaner, a toothbrush and
good old-fashioned elbow grease. I
then repeated the exercise on the tuning and volume control knobs. The
lettering on the switches was almost
absent but I decided to leave restoring
them for another time.
The metal strap covers, the switchbank end pieces and the Philips badge
all cleaned up nicely with Brasso but the
escutcheon trim was more problematic.
Rather than polish it out of existence, I
siliconchip.com.au
Philips 199 Transistor Radio – Differences
The 199 and 199AC look very similar to the model 198 but incorporate several
component and configuration changes, as follows:
(1) Bypass capacitors C11 & C14 changed from 40nF to 10nF;
(2) Neutralising capacitor C13 changed from 65pF to 50pF and connected to an overwind on IFT2’s primary rather than to its secondary;
(3) Neutralising capacitor C18 (15pF) becomes C19 (10pF);
(4) Audio input coupling capacitor C25 (2µF) becomes C26 (10µF);
(5) Treble-cut capacitor C25 (10nF) added between TR5’s collector and ground (model
199 only);
(6) Treble-cut capacitor C32 changed from 100nF to 220nF;
(7) Feedback capacitor C29 (Bass position) changed from 300pF to 200pF;
(8) Feedback resistor R22 reduced from 470kΩ to 220kΩ and its parallel capacitor C27
deleted;
(9) Feedback resistor R30 increased from 100kΩ to 220kΩ and resistor R31 replaced
with a link.
(10) As noted in the article, the 199 sets alter the connection from the ferrite rod to the
base of converter stage TR1.
(11) The 198 derives all of its audio feedback from TR6’s collector. In the model 199,
it’s permanently derived from the speaker, while Bass position feedback is still derived
from TR6’s collector and the Treble switch feedback has been omitted.
left it with the minimum of treatment.
Unfortunately, the strap stitching
had all but disappeared but that’s
also a job for another time. On the
other hand, the electronic circuitry all
looked good, with no battery corrosion
or other visible issues.
How good is it?
So just how well does the Philips
198 transistor radio perform? The
answer is “surprisingly well”.
First, the selectivity is quite narrow,
being just ± 2kHz at the -3 dB point and
±20kHz for 60dB down. It’s wider than
the AWA 897P’s with its six tuned IF
circuits, however.
The RF performance was so good it
had me rechecking my results. During alignment, I discovered that the
oscillator coil slug was jammed tight.
Another set had the same problem but
after some fiddling about with various
other adjustments, I managed to obtain
50mW output for a signal strength of
just 40µV/m at 600kHz and 42µV/m
at 1400kHz (although with only 16dB
and 15dB S/N ratios respectively).
In the absence of oscillator adjustment, the classic solution is to adjust
the antenna circuit by sliding the tuning coil along the ferrite rod. Sliding
June 2015 87
All controls except for the tuning control are mounted on the top of the case.
These include the volume control at left plus pushbutton switches for power
off, treble/power-on and bass/power-on. The lettering has mostly worn off the
pushbutton switches.
it towards the centre gives increased
inductance, while moving it towards
the end reduces the inductance. However, this adjustment on my set didn’t
offer much improvement.
I then decided on more drastic
measures in the form of a hot-air gun
applied to the oscillator coil, the intent
being to soften the wax covering sufficiently to loosen the slug. It did no
good; the slug still wouldn’t move. In
the end, rather than damage the slug
by over-zealous pressure, I left the set
with the best alignment possible.
In order to obtain the standard 20dB
S/N ratio, the signal strength needed
to be about 60µV/m at 600kHz and
65µV/m at 1400kHz. Compared to
the AWA 897 and to the even betterperforming Bush TR82C, this little
Philips set is an absolute gem. It’s
nearly as good as the most sensitive
set I’ve tested so far, the outstanding
Pye Jetliner.
It’s also interesting to compare it
to its model 196 valve predecessor.
On test, my 196 required a radiated
signal of just 25µV/m at 1400kHz for
a 50mW output and just 6µV at the
aerial terminal for the same output.
The Philips 198’s AGC control is
excellent, with the output rising by
just 16dB for an input signal increase
of some 66dB. It does go into overload
after some 40mV is fed directly into the
converter’s base. This is equivalent to
a field strength of about 500mV/metre,
so “overload” for this set means “sitting right under the tower”.
Audio performance
Like most small sets, the audio performance is adequate without being
outstanding. Its frequency response
from volume control to loudspeaker
with S3/S4 in the “Treble” position
is around 100Hz to 3.9kHz, with a
3dB peak at 250Hz. Switching S1/S2
to “Bass” position cuts the top end
response to around 2kHz.
By contrast, the overall response
when measured from the antenna
terminal to the loudspeaker is only
about 150Hz to 1kHz (S3/S4 in the
“Treble” position).
The audio stage goes into clipping at
about 160mW output, at which point
the total harmonic distortion (THD)
is around 6%. This increases to about
10% THD at 180mW. At 50mW, it’s
a bit under 1% and it maintains this
figure for an output of just 10mW. This
indicates that crossover distortion is
well-controlled.
If the battery voltage drops to 4.5V, it
clips at around 45mW. However, even
at this low supply voltage, the cross
over distortion is only just noticeable
at 35mW output.
Would I buy another?
So would I buy another model 198
or 199? Well, I did actually. It’s the
look-alike 199C which is fitted with
alloy-diffused OC170/169s in the RF/
IF end and OC74s in the output stage.
If you can get either the 198, the
199 or the 199C, you’ll have a fine little set that may appear unremarkable
compared to other designs. But once
you start using it, you’ll be reminded
of just how good it is. We’ll find out
just how good the 199C is in a forthcoming article.
Further reading
(1) For the 198 and the 199 circuits, see
Ian Malcolm’s Transistor Radio Page:
http://transistor.bigpondhosting.com/
circuits/philips198.jpg
(2) For information on the 199AC, including service data, see Kevin Chant’s
website: http://www.kevinchant.com/
uploads/7/1/0/8/7108231/199ac.pdf SC
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PRODUCT SHOWCASE
Watts Clever? This is!
This “clever” 6-way powerboard from
Jaycar is designed to automatically turn
on and off ancillary devices when a
main device is turned on or off – eg, a
PVR, DVD player, cable receiver,
amplifier, etc, when the TV set is
turned on. If each extra device took
5-10W on standby, you could save
$$$ in wasted electricity over time.
A “control” socket takes the main
device; four “auto” sockets handle
the ancillaries and an “always”
socket is powered whenever power is applied to the
powerboard. The slave sockets come on about 2-3
seconds after the “control” appliance has been turned
on. When the control appliance is turned off, the slave
sockets turn off about 9 -10 seconds afterwards.
It has a 10A total rating so should handle most domestic
applications. We envisage these could also be very handy
for the workshop or
Contact:
service bench.
Catalog number is Jaycar Electronics
MS-4081, currently (All stores and website sales)
on sale for $24.95 Tel: 1800 022 888
Website: www.jaycar.com.au
(was $39.95).
SAF Tehnika’s 2-40GHz
“Spectrum Compact”
Looking for a compact measurement
solution for the 2-40GHz licensed microwave frequency bands? Here is a range
of five powerful, ultra light, handheld
Spectrum Analysers, designed specifically for outdoor use by network and microwave radio engineers
performing equipment installation or data gathering for siteplanning purposes and a variety of other challenging situations.
They feature internal data logging, while the SMA connector
allows the units to
Contact:
integrate with any
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antenna or waveguide
4/8A Kookaburra Rd, Hornsby NSW 2077
system. No laptop
Tel: (02) 9482 1944
or other equipment
Website: www.clarke.com.au
is required on site.
Want a FREE Emona Catalog?
It’s one of the electronics industry’s most prized catalogs . . . and
you can get your own copy, free of
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A PDF copy will automatically download. And while you’re
there, check out the Emona
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siliconchip.com.au
Is it a programmable
relay? Is it a PLC?
The SG2 Series from Teco Westinghouse offers the capability of a
small PLC with the price of a programmable relay. They feature various I/O configurations of isolated
digital inputs, transistor and relay
outputs, analog inputs and expandable I/O modules. This intelligent
relay will control almost all discrete systems.
Some models have a 4x16 character LCD screen and keypad
for operator feedback and control. Five buttons on the front
allow the operator to easily view and change variables in the
program.
Functions include timers, high-speed counters, PWM, PID
loops, real time clock with summer/winter change, password
protection and heaps of other goodies, while some models
come with a built-in RS485 Modbus RTU port, which can
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$149.95+GST for the Tel: (03) 9782 5882
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Website: www.oceancontrols.com.au
NiCd/NiMH Charger kit
is cheap & easy-to-build
This ‘intelligent’ NiCd/NiMH
Battery Charger from Shapely
Designs is suitable for automatically charging a
wide range of batteries for many
applications.
It was designed for high
current and rapid
charge applications
such as cordless power
tools and model racing cars.
These battery packs are expensive
and can be difficult to purchase. This
charger uses the cell manufacturer’s recommended charge
method to safely and quickly charge batteries.
You add a suitable power supply – various options
are available, from a completely pre-assembled PCB
at $50.00 (you supply the case, etc) right through to a
bare PCB (you construct from your own components).
A pre-programmed PIC is also available for $15.00, or full
code listing for you to program
your own PIC (1612F615-I/
Contact:
SN) is on the website, along
Shapely Design
with details of the options
Website: www.shapely.asia
available.
June 2015 89
ASK SILICON CHIP
Got a technical problem? Can’t understand a piece of jargon or some technical principle? Drop us a line
and we’ll answer your question. Send your email to silicon<at>siliconchip.com.au
High-voltage probe
for multimeters
I was just wondering if SILICON CHIP
has ever presented a 6000V or 10,000V
probe adaptor for multimeters (I saw
the High-Voltage Probe for Oscilloscopes in the January 2015 issue).
Commercial high-voltage probes
are available for multimeters but they
cost many times more than the cost
of a multimeter. It could be a useful
project, if it hasn’t been done already.
(B. P., via email).
• Have a look at the EHT Stick, a
1000:1 high voltage probe for multimeters, in the April 2010 issue. It is rated
for use up to 35kV. You can see a free
2-page preview of the article at www.
siliconchip.com.au/Issue/2010/April/
A+1000%3A1+EHT+Probe
An Altronics kit for this design (Cat.
K2559) is available.
Battery charge controller
for drill packs
I recently purchased a reasonably
good battery drill from Bunnings with
their Ozito brand. As usual, the charger
is not up to scratch. I think it only
lights a couple of LEDs, one to show
power is on and the other when the
battery is connected.
I remember seeing a couple of projects in SILICON CHIP regarding drill
chargers. The battery packs (it came
with two) have 12 1.2V 1200mAh
Nicad batteries, giving a total of 14.4V.
Can you point me in the right direction as to which project I need? (M.
F., via email).
• Have a look at our Cordless Power
Tool Charger Controller in the December 2006 issue. You can see a free
2-page intro to the article at www.
siliconchip.com.au/Issue/2006/December/Cordless+Power+Tool+Char
ger+Controller
Loudspeaker protector
for SC480 amplifier
I am putting together a pair of SC480
amplifier modules (SILICON CHIP, January & February 2003) and I want to add
a Loudspeaker Protector, mainly to
avoid switch-on thumps. I was advised
by the staff at my local electronics
supplier to purchase the Loudspeaker
Protector for the CLASSiC-D amplifier
(SILICON CHIP, November & December
2012), on the basis that it can cope with
a range of amplifier supply voltages.
Is it suitable or do you have another
design that I should use?
Also, I want to connect a headphone
socket to the two amplifier modules.
Can I just use a pair of 390Ω 1W resistors to do this? (J. M., via email).
• You have been given a classic “bum
steer”. The CLASSiC-D protector is
only suitable for the CLASSiC-D amplifier, as it has a pair of optocouplers
to monitor the “protect LED” in each
channel of the amplifier module. It
will not work with any other amplifier module.
You need one of our general-purpose
loudspeaker protectors and we would
nominate the design featured in the
October 2011 issue. It is still available
as kit from Altronics (Cat. K5167) or
you can purchase the PCB from our
Online Shop. Mind you, a Loudspeaker
Protector is not strictly necessary with
the SC480 amplifier modules since
they already incorporate short-circuit
and over-current protection in the form
of a PTC (positive temperature coefficient) thermistor in series with their
outputs. This goes high in resistance
when an overload condition occurs
and reverts to a low resistance if the
fault condition is removed.
However, the PTC thermistors will
DMM Confused By DC With Superimposed 100Hz Ripple
I have a fully assembled Curra
wong valve amplifier that’s failing
its preliminary checks – specifically excessive levels of AC on all
the DC supplies. I’ve spent many
days troubleshooting this and tried
everything I can think of, including
double-checking every component
and joint.
As per the instructions, the valves
have not been inserted yet. I’ve applied power and the blue LEDs light
immediately. After 20 seconds or
so the power LED changes from red
to green. All good. I’ve attached a
power supply schematic with DMM
measurements shown.
90 Silicon Chip
The only things I can add that
might help are that if I take the same
measurements with my old moving coil meter, the DC voltages are
pretty much the same but all the AC
voltages are about half those indicated by the DMM. I’d guess that the
AC I’m measuring isn’t 50Hz. The
power LED cycles and I have lower
DC and AC voltages even when the
fuses have been removed!
I did do a lot of testing with CON7
disconnected because I didn’t want
to have to worry about the lethal
voltages all the time. I still had the
same AC and DC voltages at CON9
and on the 12V DC supply. There
were still small AC and DC voltages
on the HT supplies.
If there’s anything you can suggest I’d really appreciate it; a lot
of investment in terms of time and
money here. Please don’t publish
this if I’ve done something really
stupid! (D. H., via email).
• We think everything in your
amplifier is probably OK and that
your multimeter is confused. If you
are going to check for AC on a DC
line, you need to measure it via a
high voltage blocking capacitor. Try
using 100nF 400V.
Editor’s note: this diagnosis subsequently proved to be correct.
siliconchip.com.au
Problem With The CLASSiC DAC
Recently I built your CLASSiC
DAC project from a series of articles
in 2013 and I found that it had excellent sound and performance and
is very versatile and useful with a
wide variety of digital music sources.
I have been a keen builder of all of
your major hifi projects. However,
after successfully operating the project for about a month, it refuses to
start up normally.
During normal operation, I noticed
that there were occasions where the
unit would lock up (would not play
music but I could select inputs) but I
was always able to successfully reset
the unit by reconnecting the 9VAC
plugpack supply. I now find that the
DAC has locked up completely, is
no longer responsive to the remote
control inputs and no longer plays
music. The only sign of life is the
flashing of LED number 6 on the
front panel.
I have checked the power supply
voltages and they are all on spec.
When the DAC is first connected to
the plugpack, all the input LEDs flash
very briefly then the yellow sampling
LEDs light in sequence from right
to left before extinguishing. Finally,
after a delay of several seconds, the
SPDIF input LED (input 6) flashes
regularly. It cannot be turned on by
the remote or front switch. I have
tried changing the four switch settings but the symptoms are the same.
Also, if the SD card is inserted, it is
not offer any muting of switch-on and
switch-off thumps. If it occurs, any
switch-on thump is likely to be due
to a preamplifier you might connect in
front of the SC480 module, so if you
won’t be using a preamplifier, there
should not be any switch-on thump
and any switch-off thumps should be
very slight.
If you do decide to use the Loudspeaker Protector with the SC480
modules, you could consider omitting
their PTC thermistors and just wire
shorting links in their place. That way,
you will get slightly lower distortion
and slightly better damping factor for
your loudspeakers although the improvement will be largely academic.
And yes, your method for connecting the headphone socket will be fine.
siliconchip.com.au
not detected, as indicated by LED8
and LED6 goes into a periodic flashing mode.
Presumably the CPU is executing
a self-check routine and it has found
something amiss with the hardware,
I/O states, clock or software. I am not
sure where to fault-find with these
symptoms. What checks should I
conduct with hardware and is it
possible to check the CPU file using
the ICSP connection and verify the
checksum? I purchased the HEX
file along with the hardware from
your Online Shop but I cannot find
any way to download it to reflash
the CPU.
Having sampled how well this
project sounds I am really keen to get
it going again. (J. C., Armadale, Vic).
• There appear to be two different
things going on here. Switching an
associated power amplifier on or off
can “upset” the CLASSiC DAC and
the DAC requires a reboot to operate
properly. We think what’s happening
is that there is a large mains/EMI
spike when the amplifier’s supply
current is interrupted and this is
coupling into the CLASSiC DAC
and possibly resetting the DAC chip.
The microcontroller is still trying
to communicate with it but since the
DAC has been reset and its settings
have been lost, it doesn’t work properly. When this happens, sometimes
you still get audio but it sounds distorted, as if the bit-stream format set-
Converting watts
to lumens
On the question of different types of
lights and relative outputs, what is the
formula to convert Watts to Lumens?
For example, what is the Lumen output for a 12V 100W spotlight. (W. S.,
via Facebook).
• It all depends on the efficiency
of the particular light. So what type
of spotlight are we talking about?
Standard incandescent, Xenon, halogen, white LED or HID (high intensity
discharge)? That list ranges from the
least efficient to the most efficient;
more or less. Just to confuse the issue, spotlights also tend to be rated
in candle power and it is really not
possible to compare these parameters
ting in the DAC is no longer correct.
Adding shielding to the plastic
case could help, especially around
the CS8416 IC. Modifying the software to periodically check if the
DAC’s settings have been “lost” or
corrupted and re-initialising it if so
could also help. It’s strange because
the Reset line is actively held during
normal operation but perhaps the
EMI spike is big enough to couple
directly into the IC.
Unfortunately, we haven’t yet had
the time to fully investigate this.
You are right that the S/PDIF input
LED flashing is a sign that one of
the self-test routines has failed. At
power-up the unit checks that it can
communicate with the PLL1708, then
the CS8416, then the CS4398. LED6
flashing probably indicates a failure
to communicate with the CS4398.
We suggest that you carefully
inspect its soldering. It’s possible
that one of the leads is not properly
soldered and it was making sufficient
contact to operate earlier but due
to thermal expansion or a bump or
something else, it no longer is. You
might as well check the other SMDs
at the same time but we’d concentrate on the CS4398.
Re-flowing its leads may fix the
problem. If not, it’s possible the IC
has failed, although that seems pretty
unlikely. Check the micro also since
a soldering problem on its pins may
also have this effect.
Editor’s note: reflowing the IC pins
subsequently fixed the problem.
since candlepower is a measure of the
most intense part of the beam and that,
in turn, depends on the focus of the
lamp and any lens or reflector.
Ultimately, you have to look at the
lumen rating of the particular lamp
you are considering. In general, as
far as automotive spotlights are concerned, HID lamps and the latest high
brightness white LED lights are far
more efficient than the older halogen
types.
Question about
LED clusters
I am interested in using ultra-bright
LED clusters of the type used in the
Oatley Electronics Solar Skylight kit
but I can’t find any basic information
June 2015 91
Regulators For Low-Frequency Distortion Analyser
I noticed that the circuit for the
Low Frequency Distortion Analyser
in the April 2015 issue has a +5V rail
which isn’t used. The accompanying
text explains why two regulators
are used but is there any reason
why they can’t be replaced with
an LP2950CZ-3.3 regulator? This
particular device has a wider input
range (2.3-30V) and its use would
also save on a couple of capacitors.
Talking about regulators, are there
any hard and fast rules when it
comes to choosing the values of the
filter/smoothing capacitors on either
side of a regulator? Some circuits I’ve
seen would suggest the larger the
better but data sheets show relatively
small values. (T. B., via email).
• You could use a regulator which
will tolerate a higher input voltage
and get rid of the 78L05 but note that
this means that all the dissipation
will be in the one regulator. Given
(eg,power calculation). Is there an
idiot’s guide? (T. U., via email).
• We presume you mean the LED
clusters used in the Oatley Electronics
K328 Solar Skylight kit (SILICON CHIP,
January 2013). These use 20W LED
clusters (20W, 34V, 0.7A) each comprising two parallel strings, with each
string containing 10 series-connected
1W LEDs on a metal substrate. At 20W,
each string draws 350mA and has 34V
across it. So the typical 1W LED in the
10-LED string has about a 3.4V drop
across it when driven at 350mA. This
is just over 1W (1.19W) each.
Overall power delivered to the LED
cluster is about 23.8W, assuming a
34V voltage drop and and 700mA
current flow.
The cluster will need to have a
heatsink to dissipate the power delivered to the LEDs as there will be
considerable heat developed when
powered at 20W. While LEDs are more
efficient in producing light compared
to incandescent lamps, they are still
inefficient, overall. So expect that you
would need to dissipate at least 18W of
heat when driving the LED cluster at
20W. Ideally, the LED cluster should be
driven at a lower current than 700mA
since LED power should be de-rated
as the temperature rises.
As far as specifications are con92 Silicon Chip
the relatively low current drawn by
this circuit, that probably isn’t an
issue, even for a small TO-92 device.
Part of the reason we did it
this way is that most small 3.3V
regulators are not designed to
handle an input voltage above 6V;
obviously some do, including the
LP2950CZ-3.3 that you mention.
The other reason is that the 5V rail
is used for other purposes when the
PCB is built for the alternative function presented in this issue (ie, the
Infrasonic Snooper).
You really need to check the data
sheet for a particular regulator to
determine capacitor values and
types. Some regulators (primarily
low-dropout types) are fussy about
capacitor value and ESR. Sometimes
they provide a graph showing the
combinations of capacitance and
ESR which will provide stability
over some operating current range.
In most cases, higher capacitance is
not a problem but it isn’t unheard of
for too large a capacitance to cause
loop stability problems and possibly
also start-up problems due to the
high initial charging current.
For the input capacitor, usually
ESR is more important than capacity
because instability due to poor input
bypassing usually occurs at high
frequencies. Something like a 1µF
ceramic is fine for most regulators,
especially if there is bulk capacitance upstream.
Higher values for the output filter
capacitor usually improve transient
response but there are diminishing
returns; 100µF is usually much better than 10µF but 1000µF may not
be much better than 100µF.
Paralleling a high-value capacitor
with a low-ESR 1µF ceramic can
be a good idea to better handle fast
transients.
cerned, you could check various
manufacturer’s data on 1W LEDs to see
what they recommend with regard to
running at full power and the de-rating
with temperature.
For some information on driving
1W LEDs see www.youtube.com/
watch?v=piET0Biqo0I
#2 on to enable Top-up and switch #3
on to enable Trickle Charging (see also
the last section of the article). Follow
the instructions to set the corresponding charge rates using trimpot VR3.
Missing functions in
burp charger
I would like to use a different LCD
module from that specified for the
Spark Energy Meter (SILICON CHIP, February & March 2015). Instead, I want
use one sold by Dick Smith Electronics (Q2220) and Oatley Electronics for
many years.
I will be building at least two of
the Spark Energy Meters and I have
several of the DSE LCD modules. Both
modules are differential with 200mV
sensitivity, have an input loading of
10MΩ and provide access to the decimal points.
I can find very little information on
the Jaycar module. I cannot work out
how Dr Hugo Holden has made the
Jaycar module have a common signal
and power supply earth and still work,
so I am struggling to make the conversion (the DSE version shows how this
can be done). (G. L., via email).
• One approach to drive the Dick
Smith Q2220 LCD module (and the
Oatley Electronics module) would be
I have recently built the Burp
Charger (SILICON CHIP, March 2014)
from a Jaycar kit and everything works
except for the trickle charge and topup functions.
After checking the board for faults I
presumed the problem was in the programmed micro (IC1). I then purchased
another programmed chip from Jaycar,
with the same result. Reading from
the write-up suggests that these functions can be added later, if required.
Does this mean that they are not programmed on the IC1 purchased from
Jaycar or in the original kit? If this is
so, how do I get them programmed?
(J. S., via email).
• Trickle and Top-up modes for the
Burp Charger are set using DIP switches
S2, as shown in the panel in the lower
left corner of the circuit diagram on
page 69 of the original article. Switch
Different LCD for
Spark Energy Meter
siliconchip.com.au
to use the negative supply generator as
shown in the “12V metering system using the same battery for meter power”
diagram. Then power it from the 5.6V
rail of the Spark Energy Meter and
apply the voltage from IC3c’s output
to Vin of the Q2220 LCD module. RA
would be 10kΩ and RB 470kΩ. This
resistive divider reduces IC3c’s output
voltage by a nominal 48 times.
The calibration trimpot within the
module will need to be adjusted to
correct for the fact that the RA and RB
resistive divider only divides by 47.8
rather than 50 and for other resistance
tolerances in the Spark Energy Meter,
such as the 150Ω 5W resistor. That
calibration is as described in the Spark
Energy Meter article.
An alternative arrangement that
does not require the negative supply
may be possible. That would be with
J3 open and J1 and J2 closed. You
would need to be able to isolate the
-In terminal on the Q2220 from the
GND (ground) terminal.
Then it would be just a matter of
connecting the Common and -Vref, Vin
and -In on the Q2220 to the equivalent
COM, REL, INHI and INLO as shown
for when using the Jaycar module.
Note that for the Q2220, RB would be
a wire link and RA out of circuit.
For the decimal point, the circuit
diagram for the Q2220 shows that a
decimal point needs to be connected to
the inverted backplane that’s provided
by the collector signal of transistor Q1.
The recommended method would be
to use another 5V reed relay (the same
type as RLY1) with its coil connected
in parallel with RLY1. The contacts
would then connect across the P1
decimal point jumper connection on
the Q2220.
Spark Energy Meter
calibration query
I am building the Spark Energy Meter from the February & March 2015
issues. With the Calibrator, I had to
change the 220kΩ resistor to 270kΩ
so I could adjust the output to 250Hz.
It could not go any lower than 260Hz
without changing the resistor for
whatever reason, possibly something
at my end.
I assume when you connect the
Calibrator to the Spark Energy Meter
for calibrating the LCD to display
“100” (mJ), it requires the spark plug
be connected? Yes/No?
siliconchip.com.au
Alternative Modules For GPS
Frequency Reference
I want to build the GPS Frequency
Reference (SILICON CHIP, February &
March 2007) and I want to know if
the Garmin GPS unit is still available. If not, are there suitable alternatives please?
Also, what type of 35mm film canister is used for the mini oven. Is it a
plastic version of the metal/aluminium type? And is there a reason why
no power on/off switch was included
with this unit? (P. O., via email).
• As far as we know, Garmin no
longer makes the GPS-15L receiver
module but we believe Garmin has
a replacement module for the GPS15L called the GPS-15xL. This is a
direct replacement but with more
sensitivity. Also, both Sparkfun
(www.sparkfun.com) and Futurlec
(www.futurlec.com) have receiver
modules that should be compatible
with the GPS Frequency Reference
and they are not too high in price.
Futurlec has a MINIGPS module
which will operate from either 3.3V
or 5V, has an SMA socket which is
compatible with an external active
For some reason the LCD displays
around 170 during the calibration procedure (spark plug inserted); possibly
I have made a mistake somewhere.
I will check the resistors etc. (P, M.,
via email).
• The spark plug is is not connected
to an ignition coil during the calibration procedure. Simply apply the calibrator signal across the 150Ω resistor.
If the reading is too high and cannot be
adjusted with the LCD trimpot, there
is possibly an incorrect resistor value
on the PCB.
Note that the spark plug can be connected to the zener diode PCB but it
should not be connected to a running
ignition coil when calibrating.
Tidal clock
project wanted
What about this as a SILICON CHIP
project – a tide clock that shows high
and low tides? There are tide clocks
but they are not accurate and need calibrating often. The tide times change
frequently.
antenna and has a 1pps output.
Sparkfun has two possibilities: the
Venus GPS Logger, with the Venus638FLPx receiver inbuilt, again with
the ability to provide a 1pps output
and to work with an external active
antenna. It will apparently work
from a 3.5-12V supply.
Secondly, they have the Sparkfun
GPS Module with the Trimble Copernicus II SMD receiver mounted
on a small DIL PCB module (1.1 x
1.25”). This one seems to have all
the necessary outputs and has an
SMA socket for an external antenna.
However, it will only operate from a
2.7-3.3V power supply, so it would
need a small added regulator to work
inside the GPS Frequency reference.
The mini crystal oven in the 2007
GPS-based Frequency Reference used
a cylindrical plastic film canister.
We did not provide for a power
on/off switch on this unit because it
was designed to run from an external
DC supply and it was envisaged that
the unit would be left on for long
periods at a time.
My idea is that the tide times be
obtained from a government server
and used to indicate the hours to high
and low tides as on a tide clock. Normally the high tide is at the 12 o’clock
position and low tide at the 6 o’clock
position. Maybe a stepper motor could
be used or maybe the minute hand of
a quartz crystal clock movement with
the stepper motor directly driven by a
microcontroller.
Maybe there could be a advanced
version that also has a 7-segment display at the 12 o’clock high tide and 6
o’clock low tide position to also show
the tide times. I should add that I know
about smartphone apps to check the
tide but I think a wall clock would be
more convenient. (R. W., via email).
• We think it would be a lot of work
to program the clock for all available
sites in Australia, let alone other countries. And that is without showing the
prediction for tide heights.
We recently incorporated world
time zones into the Nixie Clock With
GPS Time (SILICON CHIP, February &
March 2015) and that really involved
June 2015 93
Light Dimmer With No Interference Wanted
I live in an area with poor AM radio reception and I find that all normal
light dimmers cause major interference when they are in use. Do you have
a solution? (M. K., via email).
• As it happens, there are two approaches which may help with your
AM reception and its susceptibility to interference. The first is to build
or purchase a noise-cancelling loop antenna. These can be very effective
in improving AM reception and we have published several designs in the
past, as can be found by doing a search for loop antenna on our website.
You can see some previews at:
www.siliconchip.com.au/Issue/2009/January/AM+Broadcast+Band+Port
able+Loop+Antenna
www.siliconchip.com.au/Issue/2007/October/AM+Loop+Antenna+
%2526+Amplifier
www.siliconchip.com.au/Issue/2005/March/Shielded+Loop+Antenna+
For+AM+Radios
However, you may also want to build one or more light dimmers which
produce no radio interference. For this you need a non-switching design
which does not employ a Triac. For that we would nominate our Deluxe
Fan Speed Controller from the May 2014 issue. This is based on a highvoltage Mosfet.
In effect, it can be regarded as a variable resistor in series with the
incandescent lamp you want to dim. This means it is much less efficient
than a Triac switching dimmer and it has a maximum lamp load of 60W.
You can see a 2-page preview at: www.siliconchip.com.au/Issue/2014/May/
Deluxe+230VAC+Fan+Speed+Controller
a great deal of programming. We also
think that since there are the smartphone apps you mention and easy access to similar information from many
websites, most readers interested in
the tides would simply go to their
computer or smart phone.
For example, in your area you can
get relevant tide information from
http://tides.willyweather.com.au/vic/
mornington-peninsula/earimil-beachsouth.html
Defective transformer
in Multi-Spark CDI
I ordered the PCB and hard to get
components from your site for the
Multi-spark CDI (SILICON CHIP, December 2014 and January 2015). After
I completed the circuit, transformer
and everything else according to your
explanation, I put the CDI on a bench
power supply.
Everything was OK and the voltage
level adjusted to 300V. Connected to
the car reluctor triggering, I adjusted
the sensitivity as described. I started
the car and it started right away, with
prompt response of the gas pedal and
everything. But 10 minutes after the
initial fire, the CDI just powered off
and it doesn’t fire.
94 Silicon Chip
I measured everything that can be
measured with an instrument, discrete
components, transformer etc and everything is OK but the oscillator is not
working and there is not 300V on the
test point. Can I check the SMD ICs
without the use of an oscilloscope
because I don’t have it?
Something has obviously burned up
because the CDI worked for 10 minutes
and then it just stopped. And every
measurable component is OK, except
the ICs which I can’t check without the
oscilloscope? Any suggestions? (A. F.,
Skopje, Macedonia).
• The most likely the problem is a
breakdown in the transformer secondary winding due to arcing or where
there is a large voltage differential
between turns on the secondary.
DI box
modifications
I built the DI box (SILICON CHIP, May
2006) which I have just taken apart to
replace a damaged socket. The circuit
of the October 2014 project is almost
but not quite identical to the May
2006 project.
I note that the unit I built has a 4.7kΩ
resistor between the jack tip and the
transformer yellow wire but the new
version only has resistors on the stereo
input and they are 2.2kΩ, not 4.7kΩ.
Does the presence or absence of the
4.7kΩ resistor alter the performance?
Should I remove the resistor from my
box?
I can easily add a 3.5mm stereo
socket with two 2.2kΩ resistors to my
2006 box. (G. C., via email).
• The May 2006 DI box had a combined mono and stereo input and
required stereo mixing resistors that
were included whether using a mono
jack or not. For a mono signal, the
input signal is reduced to one half its
original level at the coupling transformer input.
The October 2014 DI Box has separate mono and stereo inputs and this
means that the mono input need not
have attenuation resistors but only
resistors for the stereo input that acted
to mix stereo. Using separate mono and
stereo inputs as in the October 2014
DI box can give better a signal-to-noise
ratio for the mono input but since the
signal-to-noise ratio is below the noise
floor of our instruments, the improvement is not measurable.
It would be easy enough to include
the stereo socket on the May 2006 DI
Box and use the same circuitry as the
October 2014 DI Box. The use of 2.2kΩ
instead of 4.7kΩ resistors for stereo
mixing will not noticeably change the
signal-to-noise ratio – it will give a
theoretical improvement of almost
1dB, assuming a 10kΩ input impedance for the coupling transformer.
Induction Motor Speed
Controller malfunction
I am having problems with the Induction Motor Speed Controller unit
when it comes to controlling speed
via the external mode for a 240VAC
single phase motor. It works with the
internal pot but not the external mode.
It also all worked on my 3-phase 1.5kW
motor when it was first built and it has
had all the recommended modifications carried out.
After trying to get it to work on
the 240VAC single-phase motor I put
it back onto the 3-phase motor and
experienced the big bang! On inspection the current shunt resistor was
missing. I believed this happened to
your original controller (SILICON CHIP,
April & May 2012) as mentioned in the
December 2012 article.
The only thing I had forgotten to
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set were the DIP switches; they were
all in the off position. I see that you
have some parts that upgrade the
controller if it suffers failures. Would
my single-phase problems be in the
PIC microcontroller’s program? (D.
H., via email).
• We doubt the software was at fault.
If there were still software problems,
siliconchip.com.au
other constructors would be having
similar issues.
We are assuming you were changing the EXT DIP switch setting when
changing between the internal and external speed pots. We can only imagine
that a hardware fault in one channel
such as faulty soldering on the IGBT
bridge or one of the SMD capacitors
has caused strange behaviour and
eventual failure.
We can supply the up-rated IGBT
bridge IC (30A/60A) and replacement
shunt resistor for $40 + postage. Note
though that you may also need to
replace IC2 and possibly some of the
optocouplers as these may have also
continued page 96
June 2015 95
Next Issue
The July 2015 issue of SILICON
CHIP is on sale in Newsagents by
Thursday 25th June.
Expect postal delivery of subscription copies in Australia between June 22nd and July 3rd.
been damaged. The former is available
from Jaycar or Altronics.
If you’re going to replace those parts
you should inspect all the solder joints
carefully, especially the SMD capacitors, to minimise the chance of another
failure after doing the repair work.
Headphone amplifier
for hearing-impaired
My hearing aids do a reasonable
job of improving intelligibility when
listening to TV or music via an A/V
amplifier and speakers. However, for
private listening via headphones, I
was wondering if you would consider
a project for a small stereo amplifier/
equaliser between the headphone sock-
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et and ’phones which would have an
individually adjustable or programmed
boost response to mirror one’s hearing
loss curves, as programmed into the
hearing aids? What do you think? (T.
S., Tauranga, NZ).
• What do other readers think of
this idea?
LED strobe not
bright enough
I was wondering if you could assist
me. I have built the LED Strobe project (SILICON CHIP, September 2008),
as supplied in kit form by Altronics.
However, the LED does not appear to
be as bright as other 1W LED lights I
use. In fact, it is considerably dimmer.
I have powered the kit from a small
12V sealed lead-acid rechargeable
battery (12V 7.0Ah) to make it portable and re-chargeable. I need to use
the unit in day conditions (not direct
sunlight but still a fair amount of light
where I need to work) and at present
I am limited to pre-dawn and post
sunset operation.
Is there any way to modify it so that
I can increase the LED brightness? (C.
K., via email).
• The 1W LED is being driven with
the correct current, so you may need
to use the 3W white version of the
Luxeon or Cree LED to get more light.
Q1 would need to be replaced with an
IRF540 Mosfet with the gate, drain and
source in the base, collector and emitter connections for Q1 respectively.
The 220Ω resistors from RB4 and
RB5 should be changed to 22Ω. Then
the 3W LED can be driven with higher
current. This requires that the 39Ω 5W
resistor be replaced with two paralleled 22Ω 10W resistors. Additionally,
the 1N4004 diode (D1) needs to be a
SC
1N5404 (3A) diode.
Advertising Index
Altronics.........................loose insert
Emona Instruments........................ 3
Hammond Manufacturing............... 8
Hare & Forbes.......................... OBC
High Profile Communications....... 95
Icom Australia................................ 5
Jaycar .............................. IFC,45-52
KCS Trade Pty Ltd..................... 7,24
Keith Rippon ................................ 95
LD Electronics.............................. 95
LEDsales...................................... 95
Master Instruments...................... 11
Microchip Technology................... 13
Mikroelektronika......................... IBC
National Instruments...................... 9
Ocean Controls.............................. 6
Questronix.................................... 95
Radio, TV & Hobbies DVD............ 88
Sesame Electronics..................... 95
Silicon Chip Binders................ 44,96
Silicon Chip Online Shop........ 34-35
Silicon Chip Subscriptions........... 70
Silvertone Electronics.................. 27
Tronixlabs..................................... 95
Worldwide Elect. Components..... 95
X-ON Electronic Services............ 95
WARNING!
SILICON CHIP magazine regularly describes projects which employ a mains power supply or produce high voltage. All such
projects should be considered dangerous or even lethal if not used safely.
Readers are warned that high voltage wiring should be carried out according to the instructions in the articles. When working on these projects use extreme care to ensure that you do not accidentally come into contact with mains AC voltages or
high voltage DC. If you are not confident about working with projects employing mains voltages or other high voltages, you
are advised not to attempt work on them. Silicon Chip Publications Pty Ltd disclaims any liability for damages should anyone
be killed or injured while working on a project or circuit described in any issue of SILICON CHIP magazine.
Devices or circuits described in SILICON CHIP may be covered by patents. SILICON CHIP disclaims any liability for the infringement of such patents by the manufacturing or selling of any such equipment. SILICON CHIP also disclaims any liability
for projects which are used in such a way as to infringe relevant government regulations and by-laws.
Advertisers are warned that they are responsible for the content of all advertisements and that they must conform to the
Competition & Consumer Act 2010 or as subsequently amended and to any governmental regulations which are applicable.
96 Silicon Chip
siliconchip.com.au
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