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SILICON
CHIP
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Contents
Vol.19, No.8; August 2006
SILICON
CHIP
www.siliconchip.com.au
Features
8 Video Projector Survey
Looking to buy a video projector for your home theatre set-up? Don’t do it until
you’ve read this authoritative survey – by Barrie Smith
Comprehensive Video
Projector Survey – Page 8.
24 Television – The Elusive Goal; Pt.3
The first 25 years are regarded as the “Golden Age of TV” in Australia. Here’s
a nostalgic look back over those years – by Kevin Poulter
83 MoTeC Race Car Data logging, Pt.2
Making sense of all the data that’s monitored by the sensors – by Julian Edgar
Pro jects To Build
40 Novel PICAXE LED Chaser Clock
It’s got hands to indicate hours, minutes and seconds, plus chaser LEDs that
stop and freeze at the seconds hand – by Ron Russo & Clive Seager
48 Build A Magnetic Cartridge Preamplifier
Want to play back your old LPs and 78s, or convert them to CD or MP3 files?
This high-performance preamplifier will let you do the job – by John Clarke
72 An Ultrasonic Eavesdropper
Build this unit and listen to a whole new range of sounds, like the supersonic
whine of a gas leak or echo-location chirps from bats – by Jim Rowe
Novel PICAXE LED Chaser
Clock – Page 40.
90 Multi-Throttle Control For PC Flight Simulators
Add this very simple multi-throttle controller (for up to four engines) and start
flying with the big boys – by Robert Gott
102 Mini Theremin Mk.2; Pt.2
All the construction and adjustment details – by John Clarke
Special Columns
56 Serviceman’s Log
The dreaded black spot disease – by the TV Serviceman
Magnetic Cartridge
Preamplifier – Page 48.
96 Circuit Notebook
(1) Infrared Remote Extender; (2) PICAXE Battery Protector; (3) MainsDerived Timebase; (4) Automatic Daytime Running Lights; (5) Cheap 1W
Luxeon LED Driver
112 Vintage Radio
The HMV B11A 5-valve mantel receiver – by Rodney Champness
117 Salvage It!
The good bits inside flatbed scanners – by Julian Edgar
Departments
2
4
55
69
Publisher’s Letter
Mailbag
Order Form
Product Showcase
siliconchip.com.au
122
125
126
128
Ask Silicon Chip
Notes & Errata
Market Centre
Ad Index
An Ultrasonic Eavesdropper –
Page 72.
Main cover photo courtesy
Len Wallis Audio.
August 2006 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
Peter Smith
Technical Staff
John Clarke, B.E.(Elec.)
Ross Tester
Jim Rowe, B.A., B.Sc, VK2ZLO
Reader Services
Ann Jenkinson
Advertising Enquiries
Glyn Smith
Phone (02) 9939 3295
Mobile 0431 792 293
glyn<at>siliconchip.com.au
Regular Contributors
Brendan Akhurst
Rodney Champness, VK3UG
Julian Edgar, Dip.T.(Sec.), B.Ed,
Grad.Dip.Jnl
Mike Sheriff, B.Sc, VK2YFK
Stan Swan
SILICON CHIP is published 12 times
a year by Silicon Chip Publications
Pty Ltd. ACN 003 205 490. ABN 49
003 205 490 All material copyright
©. No part of this publication may
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rates, see the subscription page in
this issue.
Editorial office: Unit 1, 234 Harbord
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Postal address: PO Box 139,
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Phone (02) 9939 3295.
Fax (02) 9939 2648.
E-mail: silicon<at>siliconchip.com.au
ISSN 1030-2662
Publisher’s Letter
Video projectors give
a true home theatre
experience
This month, we have a major feature article on
video projectors, starting on page 8. It surveys
all the currently available high-definition video
projectors. This has been a mammoth task and
inevitably, by the time this issue goes on sale,
there may be some newer models on the market.
That, of course, is a permanent hazard whenever
you are trying to take a survey of rapidly moving
technology.
And make no mistake, video projector technology has moved very rapidly
in the last few years while the prices have dropped markedly. A few years
ago there were few people who could contemplate owning a realistic hometheatre system but now anyone who is thinking of buying a large plasma or
LCD set can buy a high quality video projector instead and probably save
money at the same time.
I said as much in our February 2006 issue and following my own advice,
recently purchased an LCD video projector. What a wonderful acquisition
it has been. Every time we sit down to watch a DVD I just marvel at the
picture quality and the mind-boggling technology which produces it. And
this is without high-definition DVDs which will no doubt give a further
quality improvement.
As one who well remembers the early days of TV and the common advice
as to how far away you should sit from a 21-inch TV set to avoid seeing line
structure, the picture quality we achieve today on a screen (actually just
the wall) several metres wide is quite remarkable. Screen door effect? Not
a problem! And yet only a year ago most LCD projectors could have been
criticised for this drawback.
Certainly, you still need a darkened room to enjoy a video projector but
in my case at least, that seems to be part of the ritual; you are not merely
watching TV but having a theatre experience in your own home. Apart
from having better picture quality than in a cinema, you also don’t have to
endure sound levels that are too loud, the sounds and smell of popcorn or
even having to cope with tall people sitting in front of you!
So why compromise with a plasma or LCD TV set? Or even with one of the
rear projection sets? Provided you have a suitable blank wall or space for a
large screen, you can have a high-definition video projector, for a similar or
even less amount of money. Then you can be enjoying really large pictures
in your own home. Now that is a true home theatre experience.
Leo Simpson
Note: SILICON CHIP has moved to new offices at Unit 1, 234 Harbord Rd,
Brookvale, NSW 2100. Phone (02) 9939 3295; fax (02) 9939 2648.
* Recommended and maximum price only.
2 Silicon Chip
siliconchip.com.au
MAILBAG
Mobile phones don’t
cause brain cancer
Contrary to the claim in your Publisher’s Letter (“Mobile phones have
increased risk of brain damage”) in the
June 2006 issue, there is no biological,
medical or statistical basis to assert a
link between mobile phone use and
brain cancer.
Potential human health impacts
of radio frequency energy have been
studied in great detail over the past
50 years. This has resulted in a large
body of scientific literature in this
field, covering laboratory, clinical and
epidemiological research.
Comprehensive reviews of 2200
research publications, including more
than 410 studies specifically on mobile
phones and base stations by governments and health authorities, continue
without exception, to find there is no
substantiated scientific evidence of
health effects.
The UK research team of the largest
study ever conducted on brain cancer
and published earlier this year concluded: Overall, we found no raised
risk of glioma (brain cancer) associated
with regular mobile phone use and no
association with time since first use,
lifetime years of use, cumulative hours
of use, or number of calls.
This study is part of a 13-nation
INTERPHONE project coordinated by
the International Agency for Research
on Cancer (IARC). Once all the studies
Possible risk from
cordless phones
Your comment on brain damage
from mobile phones is timely. There
was much interest in this topic
several years ago but things seem
to have gone quiet in the intervening period.
If one doesn’t use a mobile, then
the alternative (immobile?) phone
line to a local exchange may represent a similar hazard when accessed
via the ubiquitous cordless phone.
From the scant technical data for
these phones, currently available
units appear to employ similar fre-
4 Silicon Chip
are completed, the IARC, an agency of
the World Health Organisation, will do
a combined analysis of the research
which is expected to be published
later this year.
From the results collected to date,
the individual INTERPHONE studies,
including the Swedish and UK studies mentioned in your letter, have all
concluded there is no overall risk of
brain tumours from mobile phone
use. Your publisher’s claim that there
is more and more evidence of a link
is false and misleading. Moreover, it
is inappropriate to selectively report
non-statically valid results or partial
results and not also provide overall
results of these studies.
Once completed, it is expected that
the INTERPHONE project will have
examined 6000 cases of the two most
common types of brain cancer – glioma
or meningioma.
With regards to ear cancer, the
researchers from the Denmark, Finland, Norway, Sweden and UK INTERPHONE project teams recently
published their research involving
more than 4000 people in the British
Journal of Cancer and announced: The
study found no relation between the
risk of acoustic neuroma (ear nerve
cancer) and the number of years for
which mobile phones had been used,
the time since first use, the total hours
of use or the total number of calls, nor
were there any relations separately for
quencies and digital techniques to
mobiles and are packaged similarly
with close ear and head contact.
As many of us engage in much
longer conversations using a cordless phone than with a mobile, the
cumulative effect may be equally
damaging.
Perhaps you have access to sufficient technical data to reassure
cordless users of their safety. Otherwise, we may be persuaded to return
to an old VHF cordless or plug in a
corded phone.
Andrew Hanby,
Bingie, NSW.
analog or digital phone use.
Regarding the Swinburne University of Technology study on brain function, the results from this study are
inconsistent with previous research
on brain activity and the small differences found could be due to normal
biological variation or statistical noise.
In fact previous studies have found
an increase rather than a decrease in
reaction times.
Over the past five years several
studies looking at effects of mobile
phones on human cognitive functions
have been conducted by the Centre for
Cognitive Neuroscience at the University of Turku in Finland with larger
numbers of participants. These studies have not been able to replicate the
results of the earlier smaller studies.
In relation to the effects of mobile
phones on brain function, the World
Health Organisation has said: These
effects are small and have no apparent health significance. More studies
are in progress to try to confirm these
findings.
When studies find results which
are novel, such as with this one, the
well established scientific processes of
replication and validation are required
before the results can be accurately
assessed within the whole body of
scientific evidence.
The importance of replication has
recently been demonstrated in Australia by the results of the research
at Adelaide’s Institute of Medical
and Veterinary Science (IMVS). The
IMVS research could not reproduce
the results of a 1997 pilot study that
found digital mobile phone emissions
doubled the cancer rate in geneticallyengineered, cancer-prone mice.
Despite the disregard shown for this
process in your Publisher’s Letter, the
mobile phone industry continues to
endorse the importance of sound, peerreviewed and replicated research so
siliconchip.com.au
that people can be assured of the safety
of mobile phone technologies.
The gratuitous comparisons with
the tobacco industry ignore the overwhelming body of evidence and have
no place in a proper review of scientific
fact. The health risks of tobacco are unequivocal, while there is a widespread
consensus among international health
authorities and governments that radio
waves from mobile phones pose no
known risks.
Your letter also raises the issue of
driving and the use of mobile phones
and the industry agrees that drivers
should never take notes, look up phone
numbers, read or send messages. This
is an issue we take very seriously and
the Australian Mobile Telecommunications Association (AMTA) has
distributed widely its “Mobile Phones
and Driving Safety Tips” (see http://
www.amta.org.au/?Page=295).
Chris Althaus,
Chief Executive Officer,
Australian Mobile
Telecommunications Association.
Comment: if you read through the
Publisher’s Letter carefully, you will
note that there is no claim about mobile phone use and cancer but there is
a link between mobile phone use and
benign (ie, non-cancerous) tumours!
In fact, we believe that since no link
between mobile phone use and cancer has been clearly demonstrated,
that allows the industry to continue
to claim that there is no damage. We
believe otherwise. For example, interested readers may care to have a look
at http://www.newmediaexplorer.
org/chris/2004/10/20/em_fields_on_
brain_tumor_incidence_chemicals_
and_cell_phones.htm
Nor have we made any gratuitous
link between mobile phones and
cigarettes, other than the two industries have used similar techniques of
disparagement to nullify criticism.
Criticism of
early TV article
I was very interested to read your
feature item “Television, The Elusive
Goal” in the June 2006 edition of SILICON CHIP. I am not able to comment on
the Australian part of the narrative as
a whole, due to my lack of research,
however I can inform you that on one
aspect the article was in error. I refer
siliconchip.com.au
to the use of a linear amplifier to increase the 10kW power output from
the TV transmitters to 100kW ERP.
No amplifier was needed or in fact
existed for such a purpose; antenna
gain was used, as is the present case.
Note the numeric power qualification
ERP (effective radiated power, not total
radiated power).
Now I refer to the author’s comment about Mr J. L. Baird transmitting
early TV across the Clyde (Scotland)
– wrong! J. L. Baird worked for the
Clyde Valley Electrical Power Company around 1916 as an assistant
mains engineer, having been excused
military service due to ill health. It
was not until around 1923 that Baird
began experimenting with selenium
light cells with the possible application to television during 1923 in
various places. Initially, experiments
began in Guildhall St. Folkestone, to
be followed by further experiments in
Hastings (both towns are situated on
England’s south coast). Baird did not
transmit his early TV experiments but
conveyed the signals by cable as raw
video; at times telephone lines were
used (post 1926). Following the Hastings experiments with the aid of one
Victor Mills, it was reported that he
moved to Tunbridge Wells and continued with his research until finally he
moved to Soho in London’s West End
where he “perfected his basic 30-line
mechanical system”.
The BBC under governmental directive transmitted 30-line TV signals
from the London AM broadcast transmitter at Brookmans Park from 1929
until 1934 to a very limited audience. It
was stated in your article that the BBC
in 1937 proposed a solution to the system of TV to be adopted and it was: “A
competitive demonstration to be held
between the 240-line Baird system and
the Marconi 405-line system.”
First of all, it should be noted that
the 405-line system was not the Marconi system but the EMI system developed under the leadership of Sir Isaac
Schoenberg. Marconi developed the
transmitter and antenna only and the
two companies together formed a joint
holding named Marconi-EMI. Thus
the name “EMITRON” for the camera
pickup tube, albeit a development of
the ICONOSCOPE”.
It is not true that the BBC decided
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The AVR570 module (above) is a way of
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then having to manufacture your board on
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173 Boronia Rd, Boronia, Victoria, 3155
Ph. 03 9762 3588, Fax 03 9762 5499
www.jedmicro.com.au
August 2006 5
Mailbag: continued
to hold a competitive demonstration in
1937. The British government formed a
committee titled “The Television Advisory Committee” (T.A.C.) to look into
the progress of television development.
Lord Selsdon chaired its first meeting
on February 5th, 1935. It was a derivative of this committee and the British
government that decided in 1936 to
operate the two systems (Baird’s 240line and Marconi-EMI’s 405-line) on
a side-by-side trial for three months
starting on November 2nd, 1936. The
BBC provided the program content
production and operators, while
the respective equipment suppliers
provided the technical expertise and
managed the operation.
The T.A.C. had determined that the
Marconi-EMI system would be chosen
as the British TV system as early as
January 4th 1937 – the last Baird system transmission was broadcast on
January 30th, 1937. It is true that the
BBC had representation on the T.A.C.
Fishing line
fire sensor
In the May issue, one of your
readers wanted to know what sort
of sensors could be used to detect
an approaching bushfire. I am not
sure but I think it was the CSIRO
who used the following idea as
part of their research about the
rate of spread of bushfires.
They used ordinary fishing line
tensioned between two posts about
half a metre above the ground. The
fire burns through the fishing line,
causing a weight or spring to be
released. This is linked to a switch
on a clock or data logger which
records the date and time.
One advantage of the fishing
line method is that long sections
can be easily monitored, even in
heavy scrub. Disadvantages include false alarms from animals or
falling branches. The fishing line
may also deteriorate over time and
snap from the constant tension.
Ray Fitzsimon,
Nambour, NSW.
6 Silicon Chip
along with the G.P.O.
The article also states that CRT tubes
were known of before the beginning of
the 19th century, again not a realistic
statement when discussing TV. The
only tube at the turn of the century
was the Crookes tube, a laboratory
curio that demonstrated the existence
of cathode rays.
By 1902 Boris Rosing (Russia) had
produced extremely crude still shadow images using a modified Crookes
tube, again not TV. Braun (Germany)
produced the first ultra-crude oscilloscope using a Crookes tube with an
electron gun and electromagnets. It
was not a high vacuum device and relied on ionisation of residual gases for
its operation,. It had no heated cathode
and at best may have supported a two
or three-line TV system.
The first operational high-vacuum
CRTs did not appear until about 1931
from Zworykin RCA and Manfred
Von Ardenne Germany, with suitable
colour and spot size tubes appearing
in 1934. I know the article did not state
that TV-type CRT tubes were available
but the inference could be deduced by
a non-technical reader.
That Zworykin of RCA had a complete all-electronic colour TV system is
an example of journalistic license; the
system of colour synthesis can hardly
be called a complete colour TV system. A complete system must include
capture, transmission, reception and
display. Zworykin did not have such
a complete system but just a basic
patentable outline. Incidentally, Baird
reportedly demonstrated and patented
a working mechanical colour system in
England during the late 1920s.
Despite this rather long-winded
critique, I found the article to be most
informative and interesting, taking me
back on a wonderful nostalgia trip to
my early days with ATN7 Sydney during the 1960s and early 70s.
Victor G. Barker, VK2BTV,
Gorokan, NSW.
Kevin Poulter comments: Regarding
Baird transmitting across the Clyde
(Scotland) I will talk to the elderly lady
who told me her father helped Baird
and see if any new light can be shown
on the matter. Whilst she is elderly and
not from a technical background, those
were her very words.
Regarding the Marconi 405-line system, it seems that one reference book
shortened Marconi-EMI to Marconi.
Unfortunately some textbooks do have
errors. The amount of space available
for the article also prevented going into
the detail given by Mr Barker.
Regarding CRT tubes, Mr Barker’s
last sentence above says it all. We do
not ask the wrong twist to be read into
brief statements. I was incredibly impressed with the very early inventor’s
creation and the similarity to much
later TV tubes.
Queries on digital
camera articles
In your March 2006 edition on page
11, it would have been good if there
was a technical explanation given for
the delay between “shutter” and capture. It seems strange that you can have
an image on the electronic viewfinder
but not be able to preserve that image
at the instant the “shutter “ button is
pressed . . . or is that viewfinder only
a subset of the picture?
In the same edition, on page 13, in
the RGB, the B is meant to be Blue, not
the Black as printed.
In the April 2006 edition on page 30,
presumably the quote from the Japanese camera technicians was an April
Fool’s joke. Otherwise the statement
undermines the author’s credibility and
should have at least attracted an editorial comment. Such inaccurate statements may be acceptable in a camera
magazine but not in your publication
which always gives (errors excepted)
credible information.
In the April 2006 edition on page
35, a 70-210 acting as if it is 105-315
being “quite a long range“ zoom is
not correct; they are both the same in
zoom range (which is the ratio of the
longest to the shortest focal lengths)
– ie, they are both 3X. Admittedly
a significantly greater “telephoto” is
achieved at 315mm equivalent.
Graham Goeby,
via email.
Kevin Poulter comments: The viewfinder image is not the actual image
that is recorded, even in cameras with
an electronic viewfinder. It is just a
‘thumbnail’ rendition. A camera may
siliconchip.com.au
have this thumbnail or low-res image already in the
viewfinder but digital cameras have a lag, or processing
time, between the press of a shutter and actual exposure.
This lag is the same (and therefore independent of) any
shutter-speed.
Previously, lag was long enough to seriously miss action
photographs (and still is, on economy models) but has
now been reduced to acceptable levels in quality digital
cameras. There are three lags, which I will generically call:
(1) Booting on (at switch on); (2) Shutter to exposure lag;
and (3) Processing and writing lag (titled “latent period”
by some).
Lag, burst-rate and latent time are absolutely vital to
sports and nature photographers. The author has two
books by a world-renowned London-based digital photography lecturer that doesn’t even mention “lag time”
once. Regardless, nothing is more important to an action
photographer.
Latent time – the buffer memory capacity plus the write
speed of cards – is another delay. It’s not widely known
but like computer hard-drives, digital cards have a write
speed, especially as many are micro hard-drives.
When more than one image is taken in close or very close
succession, the buffer memory stores the image, to give the
card time to process it and write it to the card. Processing
includes altering the captured image to the owner-selected
settings on the camera, like contrast, colour balance, colour saturation and sharpness. The buffer-memory ensures
more photographs can then be taken, even though the last
images are still being processed.
It’s still easy to reach the limit of this capacity, after a
small number of high-resolution photographs in quick
succession. In most instances, the more expensive the
camera, the better this performance is. Unless you need
“motor-drive” performance, this delay is not anywhere
near as critical as the shutter lag-time.
When choosing a camera, it’s often best to download
the instruction manual first and read it to see if it is right
for you. Sometimes the best place to start reading any
instruction manual is the troubleshooting section, as occasionally inherent flaws are admitted.
Do not accept “burst rate” figures that refer to low-resolution file sizes, if you do not intend to use the camera in
low resolution. Some cameras specify, say, 30 frames with
no write-time delay at low resolution but that’s deceptive
if all the images are almost ‘thumb-nail’ low resolution
and therefore too small for printing.
RGB is Red, Green and Blue, as correctly mentioned
earlier in the article.
The quote from the Japanese camera technician was
no joke. He was clearly referring to the digital camera
computer’s inability to handle files other than those it
was designed for, like any other computer.
And just like any other computer, it could cause a serious or terminal crash. It’s even inadvisable to load jpg
images and cards formatted from other cameras. In fact,
digital camera instruction manuals state third-party cards
(ie, cards not the camera’s brand), are formatted by the
camera before use.
“Quite a long range” (as opposed to “quite a long zoom
siliconchip.com.au
range”) referred to the degree of magnification of distant
objects, the same as “range” refers to distance in other
optics, like a weapon’s sights.
I believe these informal (albeit ambiguous) generic references have been used by camera enthusiasts for more than
40 years, referring to a telephoto lens as a long-range zoom
and a wide-angle zoom lens as a wide-range zoom.
Certainly the magnification of the effective focal length
of lenses due to the smaller size of digital sensors is a
bonus. Lower shutter-speeds can be used before camerashake blur of images occurs. Also, less expensive optic
technology is needed to create a long (telephoto) zoom.
The only time when this effective magnification is
not a bonus is when a very wide-angle lens is required.
Then a super-wide, very expensive optic is needed, unless a composite panorama is taken. The author only
has lenses to the equivalent of 28mm, preferring to save
$1000 or much more on very wide-angle lenses. Instead,
a very wide-angle photograph is achieved by taking two,
or even three wide-angle images and joining them into a
super-wide panorama. Often the result is clearer and less
distorted as well.
The only downside – hours or even days of creative
computer time are expended in Photoshop. The finishing touch – the ultimate final tweak – is deciding if any
distortion to the final photograph will make it look even
more like a true wide-angle photograph. Normally a slight
SC
stretch of the width will be appropriate.
August 2006 7
HOME THEATRE
VIDEO PROJEC
Are you about to buy a home theatre setup?
For the very best home theatre experience
you need a high-definition projector. This
survey will help you make an intelligent
selection, enabling you discriminate
between high definition, standard definition
and data projectors and also gain an
overview of the different projector types.
By Barrie Smith
H
ome theatre should be exactly that: a room in your
home that will replicate as closely as possible the
real cinema experience. That experience can only
be created with a projector and a big screen … preferably
wall size.
While LCD and plasma TV manufacturers are busy expanding the screen dimensions of these display devices
— Samsung has got to a 102-inch (2.6 metres diagonal)
plasma screen — these massive flat screen TVs are not a
realistic solution to your needs for a home cinema.
They do have drawbacks, such as the amount of heat
generated by such a display, the weight of a 4-metre screen,
the continuing problem with plasma burn-in … and don’t
even think about the price! You may find you’ll have to
sell the house to buy one!
Talk cinema at Hoyts or in the home – and you’re talking
projection; digital video projection that can take a digital
signal from the nearest transmitter or DVD player, plus
multi-channel surround sound.
There is a big selection of projectors to consider – there
are around 30 different brands of video projector on the
Australian market. Some makers have one model in their
range, others three or more.
Investment
Let’s lay out the territory. For a home cinema, you need
a suitable room, a projector, the signal source (broadcast
programming in analog or digital, SD or HD or a DVD player)
8 Silicon Chip
Photo: Len Wallis Audio
and a multi-channel audio system. Oh, you may think it
advisable to invest in a ‘proper’ screen, with a suitably
reflective surface and matte black surrounds. Then again,
many people make do with a white painted wall.
The selected site for Cinema Chez Nous will ideally be
a largish room that can be easily darkened. A room that is
beset by high ambient light levels is patently unsuitable:
even high output projectors don’t look good in a bright
room.
Anything up to eight speakers will have to be accommodated in the scheme. A room with ‘bright’ acoustics
from parallel, painted walls is far from ideal.
Two theatres in my local multiplex could win an Oscar
for poor sound – due to precisely this reason – so at least,
in this respect, you have the opportunity to outclass your
local picture palace.
You will also need somewhere to mount the projector,
such as a floor-mounted console or an in-ceiling installation. And seating: preferably comfortable armchairs … don’t
forget King Kong lasted two hours and fifty minutes – and
the DVD version of Gone With the Wind lasts an excruciating 238 minutes (near enough to four hours!).
In the above plan I’m talking about a front projection set
up. If you want to get really classy and hide the projector
behind the screen, letting it throw the image in a back projection mode, most projectors can provide for the picture
to be laterally flipped to enable this set-up. But then you
need to allow for the extra real estate behind the screen!
siliconchip.com.au
CTOR SURVEY
There’s a lot more to all of this but you get the general
idea.
Possibly the most crucial decision you must make before
even deciding on the make or model of projector is to get
your head around the technology used to bring the picture
to the screen.
resulting in colours that slowly shift to red or blue.
DLP (Digital Light Processing)
DLP projectors (also known as DMD or Digital Micromirror Device) use a panel composed of hundreds of thousands
Liquid Crystal Display (LCD)
LCD projectors can use a single panel or three separate
LCD panels. With the latter, each panel is devoted to one
of the red, green and blue signals fed into the projector.
As light passes through the LCD panels, individual pixels
are opened or closed, to allow light to pass or be blocked.
This action produces the on-screen image.
To separate the individual pixels, LCD projectors use a
microfine grid to prevent one pixel’s light from affecting
the neighbouring pixel. Although the grid is essential to
maintain picture quality it also entails some loss of light,
which is partially absorbed as it impacts on the liquid crystal
layer. Some projectors use a micro lens array in front of the
grid to concentrate and direct the incoming light.
Most reviewers feel that LCD produces a sharper image
than the DLP approach (below) and delivers more on-screen
light output, using the same wattage lamp.
LCD’s failings (in some models) are: the “screen door
effect” caused by the inter-pixel spaces; lack of a decent
black and appreciable contrast and dead pixels may mar the
picture. LCD panels are known to slowly decay over time,
siliconchip.com.au
With 3LCD-based projectors, the white light from the
lamp is separated into the three primary colours by the
dichroic mirror/filter. Each beam of light then passes
through its appropriate colour LCD panel for processing.
Each individual pixel on the LCD panel will turn on or off
(partially or totally) to create the desired brightness and
colours needed on screen.
August 2006 9
Each Digital Micromirror Device (DMD) chip is made up
of millions of tiny mirrors. Each mirror is dedicated to an
on-screen pixel. White light from the lamp goes through
the red, green and blue (and in some cases white) colour
wheel. As the coloured light passes into the DMD, the
specific mirror will reflect it by tilting at varying angles at
a very fast speed.
Like LCD projectors, in the LCOS system white light from
the lamp is separated into the three primaries by the
dichroic mirror/filter. The coloured light rays then travel
to the liquid crystal panels, which reflect the appropriate
colors and brightness on the screen (in similar fashion to
the DMD chip).
of moving micro mirrors, controlled by underlying semiconductor electronics and a spatial light modulator.
When fed a digital video signal a DLP chip’s mirrors
can reflect a completely digital image onto the screen. The
DLP panel’s micro mirrors are mounted on tiny hinges so
they can tilt either towards or away from the light source,
creating either a light or dark pixel on the screen. This
happens several thousand times a second.
The white light generated by the lamp in a DLP projection
system passes through a colour wheel as it travels to the
surface of the panel. The colour wheel filters the light into
red, green and blue; mixtures of these primaries can produce
all the intermediate hues, such as brown, purple, etc.
High-end DLP projectors use a 3-chip configuration
with no colour wheel. Consumer projectors use a single
chip DLP panel and a colour wheel, having anything up
to eight segments, to avoid the so-called “rainbow effect”.
This is more visible to some people than others and may
be seen as a momentary multi-colour shimmer due to the
fact that not all the colours in an image are projected at
the same time.
DLP projectors can be smaller than LCD models and
produce less heat. They suffer less from the “screen door
effect” than LCD models because the control circuitry surrounding each mirror isn’t as large. DLP technology may
not be quite as colour-accurate but the colours will not
shift over the course of its lifespan.
The Interface
n quality,
the highest on-scree
If you’re aiming for
jector is
pro
d
signal source an
the interface between
important.
mposite,
in this listing have co
Virtually all the units
ks these
lin
o inputs. Being analog
broadcomponent and S-vide
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itio
fin
stard with a High De
liver
de
really don’t cut the mu
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component co
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cast signal, however a
playe
s from a decent DVD
very satisfactory result
l transfer
ita
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e)
ac
erf
DVI (Digital Video Int
high-end
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ult
HDTV and other
HDMI.
method of choice for
by
d
de
rse
pe
now being su
video displays but is
,
al) DVI-A
of DVI: DVI-D (digit
There are three types
alog]).
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tegrated [digital and
(analog), and DVI-I (in
e) is the
ac
erf
Int
n Multimedia
HDMI (High Definitio
ressed
mp
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un
ng
rti
rrier, transpo
new digital signal ca
y
the displa device
channel audio data to
10 S
ilicon
Chip
d multivideo an
Liquid Crystal on Silicon (LCOS)
LCOS is a new display technology that shows great
promise, possibly able to yield even finer resolution and
clarity than LCD or DLP but so far, there are very few LCOS
models available.
Philips, Intel and Toshiba have all explored LCOS and
“walked away”, failing to see a commercial return on the
development costs. At this stage, LCOS is more expensive
than LCD or DLP.
LCD uses transmissive technology; DLP uses a reflective
method. Consider LCOS as a hybrid of LCD and DLP. It is
a reflective technology that uses liquid crystals instead of
individual mirrors. In LCOS, liquid crystals are applied to a
reflective mirror substrate. As the liquid crystals open and
close, the light is either reflected from the mirror below or
MI to DVI
. It is possible to get HD
through a single cable
I, should
, going from HDMI to DV
cables, so compatibility
a DVI
ect
nn
wever, you cannot co
not be a problem. Ho
with HDMI input.
source to a projector
the input
listed here will handle
s
tor
jec
While all pro
n actually
n image signal, few ca
of a true High Definitio
. A model
d pixels on the screen
put all those lines an
e downag
im
n
20 pixels on-scree
that delivers a 1280x7
e result
Th
e.
ag
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el
20x1080 pix
samples the original 19
will be
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t the absolute best tha
they
is pretty good but is no
en
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rs
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obtainable with Blu-ra
are finally released.
s than
with an output of les
Note that any projector
fin
de ition.
ot be regarded as high
1280 x 720 pixels cann
n), 1080i
sca
e
720p (progressiv
An HDTV signal is in the
t.
ma
(progressive) for
(interlaced) or 1080p
siliconchip.com.au
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Tel. 02 9716 0741 Fax. 02 9798 0017 Email. wes<at>wes.net.au
August 2006 11
UHP lamps –
the heart of modern video projectors
While the technology behind the LCD, LCOS and
DLP panels used in modern video projectors is impressive, all that would count for nothing without the
UHP lamp which provides the very high light output
to drive them.
UHP stands for “ultra high performance” or “ultra
high pressure”, depending on which literature you
are reading. UHP lamps are very expensive to replace,
typically $500 to $700, and their life is typically around
3000 hours.
That very high cost is much greater than the lamps
used in 35mm slide projectors and the difference is due
to the complex technology used in UHP lamps.
A UHP lamp is a high-pressure mercury discharge
lamp. The mercury vapour arc is typically only 1mm
long, established between tiny tungsten electrodes.
When the arc is up to full temperature (at just a little
less than the melting point of tungsten – 3000° K), the
mercury vapour pressure is between 200 and 290 bar
(3000 to 4300 psi!).
The very high pressure is used to obtain a flatter
spectral output from the discharge but even so, filters
Replacing the ~$700 UHP lamp in a video projector is
not a job for the faint-hearted – in fact, it should only be
attempted by professionals with access to all the right
gear and software.
12 Silicon Chip
Extra close-up of the business end of the Sony UHP lamp,
clearly showing the spiral ignition coil wrapped around
the “burner”. You can also see the tiny arc gap in this
picture.
are required to provide a white light output.
The entire lamp (the burner) itself is typically less than
50mm long and is mounted longitudinally in a parabolic
reflector with the arc situated at the focus and usually
with a spiral electrode around one half, for igntion. The
lamp requires a high voltage to ignite it (up to 5kV) but
when established, the arc runs at around 65V and 2A
for a 120W lamp.
Hence the lamp also requires complex electronics to
ignite and drive it, similar to that used for high-intensity
gas discharge lamps in up-market cars.
Lamps should only be replaced by qualified technicians with access to the projector’s internal software to
reset the timer to zero.
Pictured at the top of this page is a selection of projector lamp assemblies from Sony, Panasonic and Philips.
This shows a selection of UHP lamp burners rated at
100W, 150W and 250W. Notice the very small gap between
the tungsten electrodes.
siliconchip.com.au
blocked. This modulates the light and creates the image.
LCOS-based projectors usually use three LCOS chips, for
the red, green and blue image data. Both LCOS and LCD
projectors deliver red, green, and blue light to the screen
simultaneously, leading to a more colour-saturated picture
than straight DLP.
LCOS advantages include: inherent high resolution;
minimal inter-pixel space which delivers a smoother and
more natural picture.
Disadvantages are: low contrast in some models, limited
lamp life and more expensive lamp cost.
Canon has spent hugely getting LCOS into shape. They
did the same thing with CMOS sensors for digital still
cameras and were so successful they managed to encourage
other companies like Sony and Nikon to follow.
But LCOS is also a fickle technology, which is why InFocus, NEC, Sony and the other big guys aren’t even dealing
with it. Bounce too much light off an LCOS chip and the
image contrast ratio goes kaput. Ratchet down the lamp
brightness to the point at which contrast is good and the
image will be too dim for viewing in large areas such as
conference rooms.
In Canon’s approach, the light is allowed to pass through
the projector’s polarising beam splitter to bounce off LCOS
chips in parallel waves to maximise contrast, and in vertical/angled waves to maximise brightness. The system
handles the projector control light in horizontal and vertical
directions independently; something never before accomplished with an LCOS projector, says Canon.
Usually, to get 2500 lumens using LCOS technology, a
projection lamp must be larger and more powerful than
those used to power equally bright LCD or DLP models.
But Canon’s system allows for the use of a smaller lamp
and smaller components, so making the projector more
portable.
The future of LCOS is still debatable but it is one to
watch.
JVC’s D-ILA
Digital Direct Drive Image Light Amplifier (D-ILA)
Be square-on
can re-centre the screen
form of keystone correction that
ing up
sett
in
s
blem
pro
ious
obv
the
ed
er digital or optical corOnce you’ve solv
image. This will consist of eith
, killing the
ling
cab
as
h
suc
ters
mat
ma,
your home cine
rection.
you next face the major
LCD/DLP/etc image
room’s ambient light and so on,
With digital correction, the
s
term
in
ure
pict
n
cree
on-s
the pixellated image
challenge of optimising the
is corrected by a reshaping of
ess.
before the picture
aren
squ
ess
of rectilinearity or
to produce on-screen squaren
screen, you
the
at
ed
aim
tly
rrec
inco
is
or
If a project
reaches the lens.
stone, both lateral and
al lens is shifted to
engage with the problems of key
With optical correction, the actu
e projectors this can
vertical.
square up the final image. In som
hallthe
is
ure
pict
en
scre
idal
ressive control of
ezo
imp
An off-square, trap
be very sophisticated and afford
em.
syst
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e
hom
up
set
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mark of a poo
the screen image.
e – to begin with – to
optical correction
In general terms, it’s best practic
Both work very well but I feel that
ned
alig
e
sibl
pos
as
ely
clos
as
of control available.
position the projector lens
has the edge, due to the amount
reasons
are
e
ther
find
then
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imum distortion as
tre.
min
with the screen cen
Optical correction also delivers
furniture in
ble:
ieva
ach
ly
rare
the screen image.
is
t
tre
spo
cen
to
mum
why this opti
the lens is actually shifted
etc.
to distortion but also
the way, inconvenient location
Digital correction can not only lead
jecpro
the
n
itio
pos
y
arel
squ
Also take great care to
introduce artefacts.
surface so that you get
ral and vertical keytor’s lens parallel to the screen
A projector which offers both late
.
tion
ge.
solu
ima
a rectilinear
stone correction is the best
market have some
the
on
ors
ject
pro
all
lly,
nkfu
Tha
siliconchip.com.au
August 2006 13
“MERLIN”
Practical and Versatile
Mini Broadcast
Audio Mixer
natural look of DLP projection.
Technology aside, the key to a satisfactory viewer
experience is the quality of the screen material used to
display the picture and the ambient light environment of
the home cinema… this is not to forget the quality of the
source programming.
Scanning method
Safe
External
Switchmode
Power Supply
Broadcast Quality
with Operational Features
and Technical Performance identical
to full sized Radio Station Mixing Panels
Permanent Installation is not required, the “Merlin” is as easy as a
Stereo System to “Set Up”,all connections via Plugs and Sockets
The “Merlin” originally designed for Media Training use in High
Schools and Colleges is a remarkably versatile Audio Mixer
Applications: Media Training - Basic Audio Production - News
Room Mixer - Outside Broadcasts - Radio Program Pre Recording On-Air Mixer in small Radio Stations - “Disco Mixer”
The “Merlin” is an Affordable Professional Audio Product
Buy one for your School, College, Community Radio Station,
Ethnic Radio Broadcast Association or for yourself
For Details and Price, please contact us at
ELAN
Phone 08 9277 3500
AUDIO
Fax
08 9478 2266
2 Steel Court. South Guildford email sales<at>elan.com.au
www.elan.com.au
Western Australia 6055
technology uses the LCOS principle and was developed
by JVC. The chip is a CMOS design which has the benefit
of placing the matrix addressing switches and electronics
right behind (not between) the light-modulating liquid
crystal layer.
The result is a 93% fill factor and virtual elimination of
the “screen door effect” so that that images can be as smooth
and natural as film with fine reproduction of details in
the original image. Other pluses are high brightness, high
resolution, high contrast and analog gradation.
Sony’s SXRD
This design appears to be similar to that of LCOS displays but with some proprietary refinements. SXRD, like
LCOS, is reflective; light passes through a liquid crystal
layer, which controls the light from each pixel, then is
reflected back out.
In the QUALIA projector, three SXRD devices (red, green,
blue) can fit on a chip measuring just 0.78 inch diagonally.
This radically increases the amount of light that can reach
the screen and reduces the “screen door” effect.
Other benefits are rapid response time with none of the
image lag that afflicts most LCD devices. A contrast ratio
of 3000:1 is claimed for the SXRD panel itself. The pure
Xenon lamp has a more even color spectrum than the UHP
lamps used in most digital home theatre projectors.
Look’n’feel
Many people find the choice of a projection display technology (LCD, DLP or LCOS) becomes a subjective chore.
Some prefer the sharpness of the LCD image or the more
14 Silicon Chip
Progressive or interlaced scanning? We’ve all grown up
with interlaced scanning in our home TV sets and it was
only when computers, using progressive scan, started to
proliferate in the domestic scene that most of us became
aware that there was another way to ‘paint’ an electronic
picture.
Interlaced scanning was initially a means to rapidly get
a picture onto the phosphor-coated screen of cathode ray
tubes; the benefit was less transmission bandwidth.
On your television set, half the lines (called a field) are
displayed at 50 times a second (Hertz) and then the other
half are woven in at 50 times per second; the eye’s persistence of vision enables the two halves of the raster to knit
a complete, flickerless video frame.
In PAL we have two interlaced 50Hz displays or 25 complete pictures in each second. NTSC uses a 60Hz system,
delivering 30 complete interlaced pictures every second.
At one stage quite a few manufacturers marketed 100Hz
TV sets, using internal digital frame stores to double up
the 50Hz interlace halves and deliver a faux-50Hz display.
This seems to have lost market appeal in recent times.
Progressive scan in the home TV appeared when high
quality sports broadcasting came into its own. With progressive scan you get 50 complete pictures every second.
LCD and plasma monitors typically only display video
signals in a progressive scan format. LCD monitors do not
use phosphors and are not susceptible to screen burn.
Ghosts
Fastidious viewers soon notice
the response lag of
LCD systems — both with flat pan
el teles and projectors.
A fast response time is the tim
e in milliseconds it
takes for the LCD cells to change
from active to inactive
and back again. A quicker respons
e time gives fast and
more accurate on screen action.
In subject matter such as sports
programming and
video games it can be annoying
to find that the ball,
cursor or similar will ‘ghost’ or ‘sub
marine’ across the
screen, without showing a smo
oth transition from A
to B.
If you like watching ultra-rapid
action in your
movies, or you’ve hooked up you
r PlayStation to the
projector to play games, you sho
uld look for one with
a response time of less than 25m
s.
ViewSonic has developed LCD
technology with a
rated response time of just one
millisecond. Using a
ViewSonic OverDrive chip, a plu
g-in replacement for a
microprocessor designed to speed
up the PC in which
it is used, it seems set to appear
in computer displays
first. No doubt the high-speed
displays will also be
attractive to other digital program
ming viewers; the
serious gaming market is one whe
re players will spend
extra dollars to achieve high perf
ormance.
siliconchip.com.au
what’s life? ...if it’s all work and no
Home Entertainment
C R E A T I O N
Home Theatre
I N N O V A T I O N
Home Automation
I N S T A L L A T I O N
I N S P I R A T I O N
64 Burns Bay Road Lane Cove NSW 2066 • Ph (02) 9427 6755 Fx (02) 9427 2490 • sales<at>lenwallisaudio.com.au
www.lenwallisaudio.com.au
Admark 14-A29SilChp
siliconchip.com.au
August 2006 15
The Listing
Some manufacturers market projectors intended for data display as well as home theatre use. Data projectors
typically have small displays, usually 800x600 pixels; far from HD quality! Only one is included in the listing.
As best as can be determined, the following listing covers the models ideally suited for home theatre, which also
usually possess all of the appropriate video interfaces. All projectors will accept signals in the PAL/NTSC/SECAM
standard as well as those in Standard and High Definition.
Considerable care was taken in the assembly of this information, quite often obtained with great difficulty. If there
is the odd discrepancy, you may have to lay it at the feet of the individual company and its negligence in assuring
that the correct info was supplied or placed on its Web site. We surely tried! So let’s get on with the listing. . .
ACER
BARCO
ACER PH110
CineVERSUM 60
(www.acer.com.au)
Display: DLP.
Native Aspect Ratio/
Resolution: 16:9/854x480.
Brightness: 1100 ANSI Lumens.
Contrast Ratio: 2000:1.
Lens: f2.5 to 2.7/20.2-24.2 mm; 1.2x zoom.
Audio/Video Interface: S-Video, composite and
component video, HDTV.
Price: $1999.
Acer has five other models, suitable for data and
video display; prices range from $1299 to $4199.
ACTION!
(www.ambertech.com.au)
ACTION! Model One Mark II (and Mark III)
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 1000 ANSI Lumens.
Contrast Ratio: 3000:1 (4000:1).
Lens: 1.3x zoom.
Audio/Video Interface: S-Video,
composite & component video, DVI-D.
Price: $10,999 ($21,750).
ACTION! Model Two
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 1000 ANSI Lumens.
Contrast Ratio: 4000:1.
Lens: 1.3x zoom.
Audio/Video Interface: S-Video, composite & component video,
DVI-D.
Price: $9999.
ACTION! Model Three
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 2500 ANSI Lumens.
Contrast Ratio: 7500:1.
Lenses: Optional range.
Audio/Video Interface: S-Video, composite & component video,
DVI-D.
Price: $42,000.
16 Silicon Chip
(www.pioneeraus.com.au)
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1024x576.
Brightness: 900 ANSI Lumens.
Contrast Ratio: 2000:1.
Lens: two 1.3x zooms.
Audio/Video Interface: S-Video,
composite & component video,
DVI.
Price: $7,999.
CineVERSUM 70-Ultra
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 1000 ANSI Lumens.
Contrast Ratio: 2700:1.
Lens: 1.3x zoom.
Audio/Video Interface: S-Video, composite & component video, DVI.
Price: $10,999.
CineVERSUM 80
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 1000 ANSI Lumens.
Contrast Ratio: 3000:1.
Lens: range of lenses.
Audio/Video Interface: S-Video, composite & component video, DVI.
Price: $19,995.
CineVERSUM 110
Display: 3DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 3000 ANSI Lumens.
Contrast Ratio: 2500:1.
Lens: range of lenses.
Audio/Video Interface: S-Video, composite & component video, SDI
(optional), DVI.
Price: $44,999.
CineVERSUM 120 Master
Display: 3DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 3000 ANSI Lumens.
Contrast Ratio: 2500:1.
Lens: range of lenses.
Audio/Video Interface: S-Video, composite & component video, DVI,
SDI (optional).
Price: $44,999.
siliconchip.com.au
BENQ
CINEO
BENQ W100
CINEO1
(www.benq.com.au)
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/853x480.
Brightness: 1100 ANSI Lumens.
Contrast Ratio: 2500:1.
Lens: f2.6-2.77/20.4-23.5mm; 1.2x zoom.
Audio/Video Interface: S-Video, composite & component video.
Price: $1499.
BENQ PE7700
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 1100 ANSI Lumens.
Contrast Ratio: 2500:1.
Lens: 1.37x zoom.
Audio/Video Interface: S-Video, composite & component video,
HDMI.
Price: $2799.
BENQ PE8720
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 1000 ANSI Lumens.
Contrast Ratio: 10,000:1.
Lens: f2.4-2.8/32.1-43 mm;
1.35x zoom.
Audio/Video Interface:
S-Video, composite & component video, HDMI.
Price: $9999.
In this company’s range are six additional models, suited for office
presentations. At 1.9 kg in weight, the PB2250 is a portable unit. The
PB8260 offers a 3500 ANSI lumens output and wireless operation.
(www.ambertech.com.au)
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: NA.
Contrast Ratio: 3000:1.
Lens: 1.3x or 1.5x zoom.
Audio/Video Interface: S-Video, composite & component video, DVI.
Price: $15,500.
CINEO3 (two models)
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 3500 ANSI Lumens.
Contrast Ratio: 7500:1.
Lens: Variable lenses.
Audio/Video Interface: S-video, composite & component video,
DVI-D.
Price: $25,999 and 29,999.
DELL
(www.dell.com.au)
1100MP
Display: DLP.
Native Aspect Ratio/
Resolution: 4:3/800x600.
Brightness: 1400 ANSI Lumens.
Contrast Ratio: 2100:1.
Lens: f2.5/28.8-34.5 mm; 1.2x zoom.
Audio/Video Interface: S-Video, composite & component video.
Price: $1299.
2300MP
(www.canon.com.au)
Display: DLP.
Native Aspect Ratio/
Resolution: 4:3/1024x768.
Brightness: 2300 ANSI Lumens.
Contrast Ratio: 2100:1.
Lens: f2.4-2.7; 1.2x zoom.
Audio/Video Interface: S-Video, composite & component video.
Price: $2199.
CANON XEED SX50
3400MP
Other Canon models, possibly more ideal as data projectors, include
LV-7240, LV-7245, LV-S4, LV-X5. All of these are portable models
and all use LCD panels. Of particular note is the LV-7565 — a “large
audience” device, using an LCD panel with 1024x768 pixel resolution,
a 4:3 aspect ratio and with a light output of 5100 ANSI Lumens in
“brighter mode”.
5100MP
CANON
Display: LCOS.
Native Aspect Ratio/
Resolution: 4:3/1400x1050.
Brightness: 2500 ANSI Lumens.
Contrast Ratio: 1000:1.
Lens: f1.85-2.5/22.0-37.0 mm; 1.7x zoom.
Audio/Video Interface: S-Video, composite & component video.
Price: $7689.
siliconchip.com.au
Display: DLP.
Native Aspect Ratio/
Resolution: 4:3/1024x768.
Brightness: 1500 ANSI Lumens.
Contrast Ratio: 2100:1.
Lens: f2.7-2.88/28.43-32.73 mm; 1.15:1x zoom.
Audio/Video Interface: S-Video, composite & component video.
Price: $2399.
Display: DLP.
Native Aspect Ratio/
Resolution: 4:3/1400x1050.
Brightness: 3300 ANSI Lumens.
Contrast Ratio: 2500:1.
Lens: f2.6-2.87/39.1-46.92 mm; 1.2x zoom.
Audio/Video Interface: S-Video, composite & component video,
HDMI.
Price: $4999.
August 2006 17
EPSON
HEWLETT-PACKARD
EMP-TW20
mp3322
EMP-TWD1 DVD player/projector
While not marketing its range as specifically for home theatre use,
HP’s models are interesting nonetheless.
(www.epson.com.au)
Display: LCD.
Native Aspect Ratio/
Resolution: 16:9/854 x 480.
Brightness: 1200 ANSI Lumens.
Contrast Ratio: 1000:1.
Lens: f1.7-2.1/16.6 mm.
Audio/Video Interface: S-Video, composite & component video.
Price: $1699.
Display: LCD.
Native Aspect Ratio/
Resolution: 16:9/854 x 480.
Brightness: 1200 ANSI Lumens.
Contrast Ratio: 1000:1.
Lens: f1.7-2.1/13.7-20.5 mm; 1.5x zoom.
Audio/Video Interface: S-Video, composite video.
Price: $2499.
EMP-TW600
Display: LCD.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 1600 ANSI Lumens.
Contrast Ratio: 5000:1.
Lens: f2.1-2.8/21.4-31.7 mm; 1.5x zoom.
Audio/Video Interface: S-Video, composite & component video, HDMI.
Price: $2999.
At the time of this listing, Epson also had another 10 or so additional
models in their range, most of which are intended for office use. An
interesting and additional trio are described as multimedia projectors; an example is the EMP-9300, which has an ANSI output of 2500
Lumens; contrast range of 1100:1; 4:3 aspect ratio and 1400x1050
resolution.
FUJITSU
(www.fujitsugeneral.com.au)
FUJITSU LPF-D711
Display: 3LCD.
Native Aspect Ratio/
Resolution: 16:9/1920x1080.
Brightness: 1200 ANSI Lumens.
Contrast Ratio: 3300:1.
Lens: f1.8-2.1; 1.7x zoom.
Audio/Video Interface: DVI-D and (via supplied selector) S-Video,
composite & component video, HDMI.
Price: $39,999.
LED light
illuminasage a major change to
It’s tiny but it may pre
projectors.
tion sources for video
tor ($1799)
FF1 Micro LED projec
its
e:
on
Toshiba has
tor … and
world’s first LED projec
is claimed to be “the
palm of a
the
lightest!” It fits in
world’s smallest and
resolution
a
s
ha
,
battery powered
le
ab
rge
ha
rec
is
,
nd
ha
io. It comes
d a 1500:1 contrast rat
of 800x600 pixels an
.
with a fold-away screen
the palm of
etProjector also fits in
ck
Po
D
LE
s
hi’
bis
tsu
Mi
750 grams
d
un
aro
s
erated, weigh
your hand, is battery op
18 Silicon Chip
(www.hp.com.au)
Display: 1DLP.
Native Aspect Ratio/
Resolution: 4:3/1024x768.
Brightness: 2400 ANSI Lumens.
Contrast Ratio: 2000:1.
Lens: 1.2x zoom.
Audio/Video Interface: composite & component video.
Price: $3108.
Two mobile models: HP mp2225 and mp3135 ($2499 and $3999).
These weigh only 1.1 kg and 1.7 kg respectively.
ANSI Lumens output: 1400/1800;
Aspect ratio/resolution 4:3/1024x768;
1400/2000:1 contrast range;
S-Video/composite & component video.
Two conference models: HP xp7010 and xp7030 ($5000 and $6000).
ANSI Lumens output: 2200/3300;
Aspect ratio/resolution 4:3/1024x768;
800/1000:1 contrast range;
NTSC/PAL/SECAM/HDTV; S-Video/composite & component video.
Three ‘versatile’ models: vp6315, vp6325 ($1499, $2299).
ANSI Lumens output: 1600/2000;
Aspect ratio/resolution 4:3;
Contrast range 2000/2500:1; S-Video & composite video.
HITACHI
(www.hitachi.com.au)
PJ-TX200
Display: LCD.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 1200 ANSI Lumens.
Contrast Ratio: 7000:1.
Lens: f1.8-2.4/20.0-31.9 mm; 1.6x zoom.
Audio/Video Interface: S-Video, composite & component video, HDMI.
Price: $3299.
While not specifically described by Hitachi as home theatre projectors, another five models range in price from $2199 to $10,999 and
offer a variety of performance specifications. Top of the range is the
CP-SX1350W, delivering 3500 ANSI Lumens output; 1400x1050,
4:3 aspect ratio/resolution; 500:1 contrast ratio; PAL/NTSC/SECAM/
HDTV; S-Video, composite & component video.
rce. The
uential 3-LED light sou
and is powered by a seq
p operation
g life, quick on-off lam
benefits of LEDs are lon
Mitsubishi
e
d and low cost. Th
with no warm up perio
600 pixels
0x
80
tive resolution of
has a DLP panel, a na
US$799.
and a 4:3 aspect ratio.
using an
msung’s Pocket Imager:
Sa
is
nt
tra
Another en
ms and
gra
0
device weighs just 69
ntrast
Ostar LED light, the
co
a
d
an
ns
of 420 ANSI Lume
has a claimed output
ratio of 1000:1.
siliconchip.com.au
INFOCUS
JVC
IN72
DLA-SX21EH
(www.internationaldynamics.com.au)
Display: DLP.
Native Aspect Ratio/
Resolution: 16:9/854x480.
Brightness: 900 ANSI Lumens.
Contrast Ratio: 2000:1.
Lens: f2.4-2.6/21.0-25.0 mm; 1.2x zoom.
Audio/Video Interface: S-Video, composite & component video,
HDMI.
Price: $2699.
IN74
Display: DLP.
Native Aspect Ratio/
Resolution: 16:9/1024x576.
Brightness: 1000 ANSI Lumens.
Contrast Ratio: 3000:1.
Lens: f2.4-2.8/21-27 mm; 1.31x zoom.
Audio/Video Interface: S-Video, composite & component video,
HDMI.
Price: $3499.
IN76
Display: DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 1000 ANSI Lumens.
Contrast Ratio: 3000:1.
Lens: f2.4-2.8/21.0-27.0 mm; 1.31x zoom.
Audio/Video Interface: S-Video, composite & component video,
HDMI.
Price: $5999.
SP7205
Display: DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 1100 ANSI Lumens.
Contrast Ratio: 2200:1.
Lens: f2.7-3.1; 1.31x zoom.
Audio/Video Interface: S-Video, composite & component video,
HDMI.
Price: $7999.
SP7210
Display: DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 1100 ANSI Lumens.
Contrast Ratio: 2800:1.
Lens: f2.7-3.1; 1.31x zoom.
Audio/Video Interface: S-Video, composite & component video,
HDMI.
Price: $10,999.
SP777
Display: DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 2000 ANSI Lumens.
Contrast Ratio: 5000:1.
Lens: Various, ranging from 1.2x to 1.55x zoom.
Audio/Video Interface: S-Video, composite & component video,
HDMI.
Price: $23,999.
siliconchip.com.au
(www.jvc-australia.com)
Display: 3D-ILA.
Native Aspect Ratio/
Resolution: 4:3/1400x1050.
Brightness: 1500 ANSI Lumens.
Contrast Ratio: 800:1.
Lens: 1.3x zoom.
Audio/Video Interface: Composite & component video.
Price: $11,999.
DLA-HX2E
Display: 3D-ILA.
Native Aspect Ratio/
Resolution: 16:9/1400x788.
Brightness: Not specified.
Contrast Ratio: 1500:1.
Lens: 1.3x zoom.
Audio/Video Interface: S-Video, composite & component video, DVI-D.
Price: $13,999.
DLA-HD2KE
Display: 3D-ILA.
Native Aspect Ratio/
Resolution: 16:9/1920x1080.
Brightness: Not specified.
Contrast Ratio: 2000:1.
Lens: 1.3x zoom.
Audio/Video Interface: DVI-D, (S-Video, composite & component
video, HDMI via additional video processor).
Price: $29,999.
DLA-HD10KSE
Display: 3D-ILA.
Native Aspect Ratio/
Resolution: 16:9/1920x1080.
Brightness: Not specified.
Contrast Ratio: 2500:1.
Lens: 1.4 and 1.9x zooms available.
Audio/Video Interface: DVI-D, (S-Video, composite & component
video, HDMI via additional video processor).
Price: $29,999.
MARANTZ
(www.qualifi.com.au)
VP-12s4
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 700 ANSI Lumens.
Contrast Ratio: 4500:1.
Lens: 1.4 and 1.9x zooms available.
Audio/Video Interface: S-Video, composite & component, HDMI, DVI
(via adaptor).
Price: $15,950.
Brightness and Contr
ast
Generally speaking, the
brighter (higher ANSI
lumens
output) the better. Sta
rt at 1000 ANSI lumen
s for most
situations. A higher co
ntrast in the on-scree
n picture
means more brilliant
whites and deeper bla
cks. Toolow-a-contrast pictur
e is not worth watching
. A figure
of 1500:1 is a start; 20
00:1 is very watchable.
August 2006 19
MITSUBISHI
(www.mitsubishi-electric.com.au)
HC900
OPTOMA
(www.ambertech.com.au)
DV-10 DVD player/projector
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1024x576.
Brightness: 1500 ANSI Lumens.
Contrast Ratio: 4000:1.
Lens: f2.4-2.6/23.0-27.6 mm; 1.2x zoom.
Audio/Video Interface: S-Video, composite & component video.
Price: $2999.
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/854x480.
Brightness: 1000 ANSI Lumens.
Contrast Ratio: 4000:1.
Lens: 1.11x zoom.
Audio/Video Interface: S-Video,
composite video, optical audio.
Price: $2499.
HC3000
H-27
Display: 1DLP.
Native Aspect Ratio/
Resolution: 15:9/1280x768.
Brightness: 1000 ANSI Lumens.
Contrast Ratio: 4000:1.
Lens: 1.2x zoom.
Audio/Video Interface: S-Video, composite video.
Price: $3499.
NEC
(www.nec.com.au)
HT410G
Native Aspect Ratio/
Resolution: 16:9/854x480.
Brightness: 1000 ANSI Lumens.
Contrast Ratio: 1200:1.
Lens: f2.0-2.48/19.5-23.0 mm; 1.18x zoom.
Audio/Video Interface: S-Video, composite & component video.
Price: $1999.
HT510G
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1024x526.
Brightness: 1000 ANSI Lumens.
Contrast Ratio: 1200:1.
Lens: f2.0-2.48/19.5-23.0 mm; 1.18x zoom.
Audio/Video Interface: S-Video, composite & component video.
Price: $2999.
CSMS
ring
ANSI method of measu
One maker feels that the
e.
not sufficiently accurat
projector brightness is
laced
maker Runco has rep
High quality projector
bert
am
t-L
foo
the
fication with
outthe ANSI-lumen speci
ht
lig
the
g
rin
ure for measu
a
em
measurement proced
Cin
products. Adopting the
y
an
put of its projection
mp
co
ent System (CSMS) the
d
ite
Standards Measurem
su
re
mo
re
we
SI standards
feels that the earlier AN
mens
ys. It says the ANSI Lu
pla
dis
eo
to industrial vid
charce
the proper performan
figure does not convey
e.
tur
kes a good movie pic
acteristics of what ma
measusing the foot-Lambert
“B
More from Runco: y
the
to
te
ica
un
mm
co
we can
be
t
urement specification
gh
mi
e in his home theatre
al
loc
customer that the imag
his
at
e
ple, than the imag
ing
1.5x brighter, for exam
try
n
tha
ful
ing
ch more mean
cinema, which is mu
ll appear.”
1000 ANSI Lumens wi
t
gh
bri
to explain how
runco.com/csms.html
There’s more at www.
20 Silicon Chip
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/854x480.
Brightness: 850 ANSI Lumens.
Contrast Ratio: 2300:1.
Lens: f2.6-2.8/22.34-26.8 mm; 1.2x zoom.
Audio/Video Interface: S-Video, composite & component video.
Price: $1999.
EP747
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1024X768.
Brightness: 3000 ANSI Lumens.
Contrast Ratio: 2200:1.
Lens: 1.2x zoom.
Audio/Video Interface: S-Video, composite & component video, DVI-D.
Price: $4299.
HD-721
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x768.
Brightness: 1300 ANSI Lumens.
Contrast Ratio: 5000:1.
Lens: 1.2x zoom.
Audio/Video Interface: S-Video, composite and component video,
HDMI, DVI-D.
Price: $4750.
H-78
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 1000 ANSI Lumens.
Contrast Ratio: 3800:1.
Lens: f2.4-2.69/28.3-38.2 mm; 1.35x zoom.
Audio/Video Interface: S-Video, composite & component video, HDMI.
Price: $11,999.
PANASONIC
(www.panasonic.com.au)
PT-AE900
Display: 3LCD.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 1100 ANSI Lumens.
Contrast Ratio: 5500:1.
Lens: f1.9-3.1/21.7-43.1/2x zoom.
Audio/Video Interface: S-Video, composite & component video, HDMI.
Price: $3299.
The company has a wide range of data and commercial projectors.
siliconchip.com.au
RUNCO
SANYO
CL410
PLVZ4
(www.network-et.com)
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1024x576.
Brightness: 800 ANSI Lumens.
Contrast Ratio: 2500:1.
1.3x or 1.6x zoom.
Audio/Video Interface: composite & component video, DVI.
Price: $6999.
CL420
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 1200 ANSI Lumens.
Contrast Ratio: 2800:1.
Lens: Optional lenses.
Audio/Video Interface: composite & component video, DVI.
Price: $11,000.
CL610
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 1150 ANSI Lumens.
Contrast Ratio: 2200:1.
Lens: NA.
Audio/Video Interface: composite & component video, HDMI.
Price: $16,000.
CL810
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 1250 ANSI Lumens.
Contrast Ratio: 3100:1.
Lens: Optional lenses.
Audio/Video Interface: composite & component video, HDMI, DVI.
Price: $20,000.
VX-1000d
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 1500 ANSI Lumens.
Contrast Ratio: 3300:1.
Lens: 1.3x zoom.
Audio/Video Interface: S-Video, composite & component video, DVI.
Price: $30,000.
VX-2c
Display: 3DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 2500 ANSI Lumens.
Contrast Ratio: 2800:1.
Lens: Range of optional lenses.
Audio/Video Interface: S-Video, composite & component video, DVI.
Price: $79,999.
Runco has other models which begin at $53,000 and rise to
$350,000. ANSI Lumens figures of 8000 are achieved with the latter.
siliconchip.com.au
(www.sanyo.com.au)
Display: 3LCD.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 1000 ANSI Lumens.
Contrast Ratio: 7000:1.
Lens: 2x zoom.
Audio/Video Interface: S-Video, composite & component video,
HDMI.
Price: $3999.
PLV80
Display: 3LCD.
Native Aspect Ratio/
Resolution: 16:9/1366x768.
Brightness: 3000 ANSI Lumens.
Contrast Ratio: 1000:1.
Lens: f1.8-2.1/48.4-62.8 mm; 1.3x zoom.
Audio/Video Interface: S-Video, composite & component video.
Price: $10,999.
SHARP
(www.sharp.net.au)
PGMB60X (and PGMB70X)
Display: 1DLP.
Native Aspect Ratio/
Resolution: 4:3/1024x768.
Brightness: 2400 ANSI Lumens
(PGMB70X – 3000).
Contrast Ratio: 1200:1
(PGMB70X – 2000:1).
Lens: 1.5x zoom.
Audio/Video Interface: S-Video,
composite.
Price: $4299
(PGMB70X – $4999).
XVZ2000
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 1200 ANSI Lumens.
Contrast Ratio: 2500:1.
Lens: 1.5x zoom.
Audio/Video Interface: S-Video, composite & component video.
Price: $5499.
XVZ1200
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 900 ANSI Lumens.
Contrast Ratio: 5500:1.
Lens: 1.35x zoom.
Audio/Video Interface: S-Video,
composite & component video, DVI.
Price: $10,999.
This company serves the market well with alternative models, configured as portable projectors and for data projection.
August 2006 21
SIM2
SONY
DOMINO 30H
VPL-HS60
(www.audioproducts.com.au)
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: NA.
Contrast Ratio: 2800:1.
Lens: 1.3x zoom.
Audio/Video Interface: S-Video, composite & component video,
HDMI.
Price: $9999.
HT280
(www.sony.com.au)
Display: 3LCD.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 1200 ANSI Lumens.
Contrast Ratio: 10,000:1.
Lens: 1.6x zoom.
Audio/Video Interface: S-Video, composite & component video, HDMI.
Price: $3499.
VPL-VW100
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1024x576.
Brightness: NA.
Contrast Ratio: 2300:1.
Lens: 1.4x zoom.
Audio/Video Interface: S-Video, composite & component video, HDMI.
Price: $8999.
Display: 3SXRD.
Native Aspect Ratio/
Resolution: 16:9/1920x1080.
Brightness: 800 ANSI Lumens.
Contrast Ratio: 15,000:1.
Lens: 1.8x zoom.
Audio/Video Interface: S-Video,
composite & component video, HDMI.
Price: $14,999.
HT300E
QUALIA 004
Display: 3DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: NA.
Contrast Ratio: 3500:1.
Lens: 1.4x zoom.
Audio/Video Interface: S-Video, composite & component video, HDMI.
Price: $14,999.
C3X Lite
Display: 3DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: NA.
Contrast Ratio: 6500:1.
Lens: optional 1.4x or 2.3x zoom.
Audio/Video Interface: S-Video, composite & component video, HDMI.
Price: $24,999.
C3X
Display: 3DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 2500 ANSI Lumens.
Contrast Ratio: 6500:1.
Lens: optional 1.4x or 2.3x zoom.
Audio/Video Interface: HDMI, S-Video, composite & component video.
Price: $29,999.
Wide or Tele
one probnnected with the keyst
A factor not directly co
difficult
in
lp
he
e. You may need
large
lem is screen image siz
too
or
big
too
is
final picture
situations where the
with the fitted lens.
fashion to
ses operate in similar
Navitar conversion len
normal
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of
nt
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those on digital came
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ose
ch
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widen the image by 1.5
.
to re-site the projector
.com.au)
nology: (www.ambertech
Through Amber Tech
22 Silicon Chip
Display: 3SXRD.
Native Aspect Ratio/
Resolution: 16:9/1920x1080.
Brightness: 1600 ANSI Lumens.
Contrast Ratio: 15,000:1.
Lens: Interchangeable range.
Audio/Video Interface: S-Video,
composite & component video,
DVI-D, HDMI.
Price: $POA.
TOSHIBA
(www.pioneeraus.com.au)
P8
Display: 1DLP.
Native Aspect Ratio/
Resolution: 4:3/1024x768.
Brightness: 1500 ANSI Lumens.
Contrast Ratio: 2100:1.
Lens: f2.0-2.88/28.43-32.73mm; 1.2x zoom.
Audio/Video Interface: S-Video, composite video.
Price: $3299.
S25
Display: 1DLP.
Native Aspect Ratio/
Resolution: 4:3/1024x768.
Brightness: 1800 ANSI Lumens.
Contrast Ratio: 2000:1.
Lens: f2.0-2.2/18.82-21.84 mm; 1.2x zoom.
Audio/Video Interface: S-Video, composite & component video.
Price: $1999.
MT700
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 1000 ANSI Lumens.
Contrast Ratio: 2500:1.
Lens: f2.0-2.2/18.82-21.84 mm; 1.2x zoom.
Audio/Video Interface: S-Video, composite & component video, HDMI.
Price: $4999.
siliconchip.com.au
VIEWSONIC
YAMAHA
PJ256D
DPX-530S
(www.viewsonic.com.au)
(www.yamahamusic.com.au)
Display: 1DLP.
Native Aspect Ratio/
Resolution: 4:3/1024x768.
Brightness: 1600 ANSI Lumens.
Contrast Ratio: 2000:1.
Lens: 1.2x zoom.
Audio/Video Interface: S-Video, composite & component video.
Price: $2699.
Display: 1DLP.
Native Aspect Ratio/
Resolution: 16:9/1024x576.
Brightness: 1500 ANSI Lumens.
Contrast Ratio: 4000:1.
Lens: f2.72.6/23-27.6 mm; 1.2x zoom.
Audio/Video Interface: S-Video, composite & component video, DVI-D.
Price: $4999.
PJ755D
DPX-1300S
Display: 1DLP.
Native Aspect Ratio/
Resolution: 4:3/1024x768.
Brightness: 2800 ANSI Lumens.
Contrast Ratio: 2000:1.
Lens: 1.2x zoom.
Audio/Video Interface: S-Video, composite & component video.
Price: $3099.
PJ1172
Display: 3LCD.
Native Aspect Ratio/
Resolution: 4:3/1024x768.
Brightness: 4500 ANSI Lumens.
Contrast Ratio: 800:1.
Lens: 1.5x zoom.
Audio/Video Interface: S-Video, composite & component video.
Price: $6999.
PJ656
Display: 3LCD.
Native Aspect Ratio/
Resolution: 4:3/1024x768.
Brightness: 2100 ANSI Lumens.
Contrast Ratio: 400:1.
Lens: 1.2x zoom.
Audio/Video Interface: S-Video, composite & component video.
Price: $2499.
PJ862
Display: 1LCD.
Native Aspect Ratio/
Resolution: 4:3/1024x768.
Brightness: 3100 ANSI Lumens.
Contrast Ratio: 400:1.
Lens: 1.2x zoom.
Audio/Video Interface: S-Video, composite & component video, DVI-D.
Price: $3999.
Lamp Life
mes as
and have a life someti
Lamps are expensive
when
ts
en
. Budget for replacem
2000
short as only 2000 hours
y:
wa
s
thi
tor. Figure it out
re
mo
you first buy the projec
or
00
10
of
ng
to the viewi
me
co
hours lamp life equates
ll
sti
u
yo
see
l
u’l
ths and yo
movies but do the ma
of cinema-going.
st
co
the
n
tha
out better
ments;
ened in warm environ
ort
Lamp life will be sh
p has
lam
the
…
ns
screening sessio
another factor is long
the projecd make sure you clean
no chance to cool. An
an economy
. Many projectors have
tor’s air filter regularly
longing its
pro
p is under-run, so
mode, in which the lam
e.
tur
pic
r
ghtly dimme
life but delivering a sli
siliconchip.com.au
Display: 1 DLP.
Native Aspect Ratio/
Resolution: 16:9/1280x720.
Brightness: 800 ANSI Lumens.
Contrast Ratio: 5000:1.
Lens: f2.7-5.0/ 24.3–38.9 mm; 1.6x zoom.
Audio/Video Interface: S-Video, composite & component video,
HDMI, DVI.
Price: $16,999.
Useful Web Sites
An excellent source
of varied information
can be
found at www.proje
ctorcentral.com and
www.bigscreenforums.com …
in trawling the latter,
take some
of the comments with
a grain of salt.
More info on home the
atre can be found at ho
metheater.about.com (note
the US spelling – “thea
ter”.)
Another useful site is
www.ausmedia.com.
au …
home of retailer AIM
Digital Imaging. Revie
ws and
explanatory data galor
e.
Similarly, www.dtvfor
um.info is a very activ
e discussion site.
There is an excellen
t glossary on Toshiba
’s Web
site: www.isd.toshiba
.com.au/projectors/pr
ojectors/
service-glossary.shtm
l … although it omits
such subjects as HDMI, DVD-I
and S-Video.
Another can be found
at www.hdtvinfoport.
HDTV-Glossary.html
com/
Great tutorials are fou
nd on www.projectorp
eople.
com/tutorials
Footnote:
If you need to search
for info on video projec
tors, as I
have, I must wish you
the Best of British …
some major
makers’ Web sites are
of little help, with som
e superseded
models still listed and
some of the specs just
plain wrong,
mixed up as they are
with specs from mode
ls intended
for other markets.
As paying customers,
we deserve better.
SC
August 2006 23
Television’s
Golden Age
Part 3 –
By Kevin Poulter
With next month marking a half century of television
in Australia, this third and final installment in our
unashamedly nostalgic series looks at what, to many, is
regarded as the Golden Age of TV: its first twenty-five years.
T
elevision, like radio before, became the centre of
household entertainment, values and enhanced education. Essential to many, television created employment, with a host of manufacturing, service, finance, retail
and related businesses.
The all-important ingredient was successful shows, as this
led to more television receivers purchased, enabling growth
in all areas. “In Melbourne Tonight”, hosted by Graham
Kennedy, began in 1957, its success relying on slapstick
comedy and light entertainment format.
To the shock and dismay of advertisers, Graham soon
lampooned their products. After initial complaints, advertisers were stunned to see their sales – and profits – growing
as a result.
24 Silicon Chip
Most drama was American, with a smattering of British
content, so nothing has changed. Teenage programs were
also popular, like Brian Henderson’s Bandstand on Sydney’s TCN9, Mickey Mouse Club, Brian Naylor’s Swallow
Junior and the ABC’s Six O’Clock Rock, hosted by Johnny
O’Keefe.
This Day Tonight commenced on the ABC in 1967, soon
reaching top popularity. TDT was initially flown all over
Australia from its Sydney base, for telecast by ABC channels in other states.
By 1969, television reached 95% of Australia’s population, with 45 commercial and 39 national stations keeping
our nation entertained.
Per capita, city stations provided more TV channels
siliconchip.com.au
than in USA or Europe. 81% of homes had
a television set.
Nearly all drama on Australian TV was
produced overseas – a massive 97% – so rules
were changed, requiring stations to present
Australian-produced drama programmes for
at least two hours a month, in peak viewing,
between 7pm to 9.30pm.
Safe at any voltage?
Right through the era, valves remained the
dominant technology, with plastic cabinets
and solid-state slow to take on.
Technicians needed to learn about television, so schools were commenced at the
Royal Melbourne Technical College (RMIT)
in 1955 and the ABC Sydney training school
in St Peter’s Church Hall, opposite their radio
studios in Forbes Street.
HMV’s Television service manual for their
all-valve chassis type M2 offers an insight to
the state of technology at the time. . .“The
“BP Australia presents . . . PickABox, with Australia’s favourite compere, Bob
high voltage of the picture tube anode (16,000 Dyer . . .” Bob (shown here with Dolly Dyer) was one of relatively few radio
volts EHT) will give an unpleasant shock, but personalities who made a successful transition to the new medium, television!
doesn’t supply enough current to give a fatal
burn or shock. However, secondary human
Shocking!
reactions to otherwise harmless shocks have been known
to cause injury”.
In the 60s, RMIT’s television department had about 25
Further – “the picture tube is highly evacuated and if brobare Astor chassis for students to work on. After initially
ken, it will violently expel glass fragments. When handling
powering up the Astor to measure voltages, I suddenly rethe picture tube, always wear goggles.”
ceived a karate blow to the back of the neck. Students were
I never witnessed technicians wearing goggles but some
known to perform occasional pranks but on looking around,
‘scientific minds’ threw a tube into the dump-master from
nobody was close by.
a building’s second story, authoritatively confirming that
Lesson learnt – don’t wear the latest fashion tie with metal
there is indeed an implosion on impact!
highlight threads near a live set!
Returning to the HMV M2, this receiver boasted a turret
tuner for precise alignment of the oscillator on each channel,
through the front, an overall frequency response within 6dB
from DC up to 4.7MHz, DC coupling from the video detector
to the picture tube – ensuring full black, instead of greys in
the shadows and night scenes – time-gated AGC, to nearly
eliminate impulse noise, like ‘aircraft flutter’, plus many
more leading edge technologies.
A hinged vertical chassis made servicing much easier. (see
photo overleaf). The sound from early console sets with an
eight or twelve-inch speaker was most impressive too, even
by (especially by?) today’s standards.
Proof of the design and build quality of the higher-priced
early sets is some still work, or are capable of reception after
their leaky capacitors are replaced.
CRTs remain the best.
Now, after fifty years as the only medium to present TV
images, the cathode ray tube is on its way out, sorely missed
by many professional video editors and graphic artists.
Despite the huge size and ‘cartoon colour’ of plasma
screens, video editing staff continue to use ageing CRTs, as
they exhibit a more accurate picture.
Sony manufactured their last CRT TV in 2005 and others
are following suit, so soon there will be no choice.
An Astor 1956 console, with 21-inch tube displaying
children’s host, Happy Hammond.
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A potted history
From the fifties to the seventies, a vast range of new proAugust 2006 25
like a live broadcast of football, beamed from Geelong to
Melbourne.
Originally partners, ATN7 Sydney established a microwave link in 1957, connecting to GTV9 Melbourne. Five
mountain-top microwave links were employed in an
exercise called Operation Kangaroo.
1958 was an eventful year too, with “Leave it to Beaver”
achieving the first registered TV audience of over one million viewers. TCN9’s “Brian Henderson’s Bandstand” commenced, a variety music program that launched the careers
of many Australians during 14 years of broadcasting.
This was the year TV WEEK magazine started annual
TV awards. GTV9’s Graham Kennedy won the Gold Award
(for most popular TV personality) and named the awards
the Logies, after TV pioneer John Logie Baird. The first Logie
awards were held in a hotel, not televised until 1965,
though they were presented on IMT for a few years.
Video recording – at a premium price.
Sets like this HMV M2, featured a swing-out chassis,
making servicing more accessible.
grammes, stations and networks appeared, so only highlights
are mentioned here. Links with extensive details are found
in the references web page, shown at the end of this article.
On March 31 to April 1, 1957, the first Telethon was
broadcast, with Graham Kennedy, a young radio announcer,
making his first appearance. Producer Norm Spencer is later
titled the ‘King Maker’.
Shortly after, “In Melbourne Tonight” commenced five
nights a week in the “not for kiddies” time-slot of 9.45pm.
IMT’s ninety minutes of live, slap-stick humour, singing
and acts entertained till 1971.
Stars were created, like Bert Newton, Philip Brady, Ernie
Sigley and Denise Drysdale. Fifty years later, many of these
stars continue broadcasting.
Microwave transmission, still utilised for links, was available from the beginning, enabling line of sight transmissions,
Video recorders were a must-have for television stations.
Nearly three years after first broadcasting, GTV9 purchased
their first video recorder, in 1959, for 35,000 pounds.
Features like still-frame and slow-motion were not available, though later a PYE slow-motion adapter was added
to Nine’s unit. (see photo) During 1960, HSV7 acquired
an RCA videotape recorder for 45,000 pounds, including
spare parts.
The challenges for designing improved videotape recorders included creating new features and better quality, with
less tape and equipment costs.
A leading Ampex engineer was playing with his dog, twirling a spiral of toilet paper. Then an inspiration hit him – why
not spin the video heads in an angled pattern?
In 1978, one inch helical-scan reel-to-reel video recorders became available, offering shuttling and still-frame, but
the sound plus picture was not as good as the quad-head
system.
Stations equipped with video recorders saved money by
A Videotape department in 1967. In the early ‘60s, each
machine cost as much as 45,000 pounds.
26 Silicon Chip
siliconchip.com.au
The videotape recorders of the 60s were good quality, but lacked still frame and slow motion. Later, PYE made an
adapter for slow motion.
recording over programmes again and again, until dropouts
on the tapes were excessive. Then tapes were thrown out.
So a combination of mainly live theatrical-style shows,
lack of VCRs, re-using tapes, disposing of used tapes and
no insight they were producing history, means very little
local TV footage from the era remains.
As we mentioned in the first part of this series, even the
famous, grainy, Bruce Gyngell “Welcome to Television”
snippet that “records” the commencement of TV in Australia
is itself a fake, recreated for posterity quite some time after
the original in 1956!
Fortunately, though, over the years some dumped tapes
and equipment were rescued by enthusiastic staff. Even
though they risked the wrath of station management at the
time, years later those same stations began to borrow collectors salvaged video cameos of the era.
Equipment also met the dump-master and still does, with
just a few saved for history and especially useful for dubbing
old programmes to DVDs.
a multi-way plug onto the remote lead and run a suitably
socketed cable under the floorboards from their watching
position to where the TV receiver sat, so as to avoid a cable
cluttering the lounge room floor!
One of the first cordless units was the Admiral ‘Son-R
remote’, appearing around 1960. It was an utrasonic unit –
infrared was many years away. Inside the remote control,
two solid brass rods were held by taut wires and tuned to
ultrasonic frequencies, about 40kHz and 41kHz, one controlling the tuner and one for volume. Pressing a black button
connected to a strip of spring steel resulted in a ‘piano
string striker’ effect.
A microphone, discreetly built into the TV cabinet fed
an amplifier/frequency splitter, connected to stepper-motors.
The turret tuner had its usual mechanical indent for a positive stop.
The Son-R unit was very rare but is another example of
early technology that led to the remote controls we enjoy
and expect today.
Pass me the remote.
Renewing old tubes
Remote controls for TVs were uncommon and unwieldy,
usually connected to the TV receiver via a long cord. It
wasn’t uncommon for the more technically minded to fit
Television picture tubes were very expensive, with early
predictions of short picture-tube life. So refurbishing factories started to open.
siliconchip.com.au
August 2006 27
The Telecine department in TV stations was a busy vital area. Film was transferred to tape or broadcast. On the top right,
an Astor table-top receiver is used as a monitor (this receiver was also used in many homes).
In today’s ‘throw-away’ society, its hard to imagine these
companies offered a total service – collection, delivery,
payment for the faulty tube, refurbish – and still sold the
rejuvenated tubes much cheaper than new, including a 12
month warranty!
Rebuilding of the picture tubes commenced with inspection under ultraviolet light and any scratches on the tube
face removed. Then cleaning and washing in a chemical
solution followed. Next, a hot wire was placed around the
neck to crack it. This causes a gradual rush of air into the
tube, then the gun fell off.
After mounting the tube on a lathe, the glass neck was cut
to within one inch of the flare of the cone. A new gun was
then affixed to the tube, by heating, using air and gas jets.
Finally, the gun was placed in a 725°F oven for two hours,
while pumps evacuated the tube.
The coax cable
A television breakthrough, the coaxial cable was laid in
1960, between Sydney and Melbourne. During the same year,
Sir Frank Packer of Consolidated Press purchased GTV9 for
three million pounds.
Toward the end of October 1960, a Marconi colour television system was demonstrated in various venues around
Australia, including at the Royal Melbourne Hospital.
Australian television receiver licences in 1961 totalled
1,229,084, with New South Wales owning 490,922, Victoria
402,465, South Australia 127,519, Queensland 117,386,
Western Australia 71,044 and Tasmania 19,748.
Technicians were becoming increasingly concerned the
28 Silicon Chip
morning test pattern broadcasts would cease, even proposing
a levy system to pay for its continuance.
Don’t blame us!
Television receiver manufacturers were concerned their
well-designed units connected to low-performance antennas or poor installations were presenting unsatisfactory
pictures.
Companies such as Kriesler therefore published antenna
selection and installation guides, advising nuisance-calls
to TV technicians regularly uncovered poor antenna installations.
“The situation is a difficult one,” it said, “because while
the service technician may suspect a faulty aerial system to
be the cause, he has to exhaust the other possibilities first,
because of the labour and expense involved in re-installing
the aerial.”
Kriesler then covered a multitude of factors, like the
quality of the aerial, gain, use of many feeder stand-offs (to
avoid feeder flutter), twists in the 300W ribbon, avoiding
acute angles in the feeder, refraining from horizontal runs
– especially near the ground or gutter, avoiding resting on
metal, salt areas, use of coax to minimise ghosting, checking
loop resistance and much more.
Around this time, technicians such as John Williamson
commenced replacing fault-prone paper capacitors with
polyester. In fact some technicians regularly quoted to replace
all the most vulnerable problematic capacitors to reduce
service-calls. In time, John found this upgrade did indeed
reduce service-calls.
siliconchip.com.au
The famous “Studio9” at Television City, Richmond, Victoria. Note the impressive lighting grid at the top of the picture –
all run by an equally impressive electronic organ-like control panel, shown here insetted into the main pic.
Outer space technology and Television.
The world was exhilarated with space achievements, so
television advertising gratuitously included references to
space exploration, linking the latest sets to the excitement.
Telstar, the world’s first communications satellite, was
launched in 1962 enabling live TV pictures to be transmitted
from the USA to France.
Bandstand commenced with Brian Henderson. Performers
who rocketed to fame included Col Joye, Peter Allen, Helen
Reddy, the Bee Gees, Little Pattie, The Delltones, Judy Stone,
Sandy Scott and Lucky Starr.
The TV station monopoly situation prompted the Government to establish a third commercial network in 1963.
Newspaper magnate, Rupert Murdoch, was an unsuccessful
applicant and the licence was awarded to Sir Reginald Ansett,
of the national airline company, Ansett-ANA. This was the
beginning of the TEN network.
TCN 9 and GTV 9 secured the rights to the first coaxial
soccer ball
GO TO www.rsaustralia.com
Easier access to over 150,000 electronic, electrical and industrial products
siliconchip.com.au
August 2006 29
Filming the Mt. Dandenong Bushfires in 1962 atop an OB
van. Cameraman is Russ Sefton, using a PYE camera and
telephoto Canon lens. Note microwave dish, to feed the
images to the station.
cable between Melbourne and Sydney. On November 30,
the Federal Election was seen simultaneously in Sydney,
Melbourne and Canberra.
Links were still not permanently established to most
states, so Test Cricket was broadcast live and direct
from Adelaide, using a transmitter link fitted in a DC3
aircraft.
Australian made – for now.
AWA was the only Australian manufacturer of television
transmitters, just one of about ten major manufacturers of
TV transmitters in the world. The first Australian-built TV
transmitters were supplied to BCV-8 Bendigo, and GMV-6
Shepparton, both designed and built by AWA.
In the same year, AWA completed a further fourteen
complete 10kW TV transmitters for the Australian Post
Office. All the electronic parts of TV transmitting systems
including Vidicon cameras, (except Image Orthicon cameras) were manufactured by the company.
Sony’s first all solid-state TV receiver, 8-301W, with 23
transistors, 17 diodes and 2 high-voltage rectifiers. The
tube was an eight-inch and the set could be operated from
mains or two 6-volt lead-acid unspillable batteries in an
external screw-on battery box. The unit weighed only 13
lbs and consumed a tiny 11 watts. This model performed
flawlessly and was instrumental in the Sony brand being
widely accepted in USA.
30 Silicon Chip
The following years saw rapid progress with the introduction of printed circuit boards, hybrid circuits, solidstate devices and the introduction of many models and
screen sizes. In fact Admiral televisions had printed circuit
boards from the onset. By 1968 when the futuristic 17-inch
Telstar portable was released, AWA had manufactured
500,000 receivers.
The government insisted on local manufacturing content
and AWA Television receivers were proudly made entirely
from components manufactured in Australia. In fact AWA
fabricated all but the capacitors, resistors and some sundry
sockets in-house.
Considering the large number of component parts – over
2000 in a receiver – their performance and reliability proved
to be outstanding, a credit to the Australian industry.
However, in just a few short years, this was totally undone by government suddenly slashing tariffs, so Australian television and electronics production rapidly ceased.
Brisbane and Adelaide secured new third channels
(network TEN) and a second station commenced in Perth,
during 1965. The Australian Broadcasting Control Board
had advised against extra stations and introduced a fifty
percent Australian content requirement in peak viewing
for commercial television stations.
Satellite connection.
Satellite telecasting arrived in Australia in November
1966, through the earth station at Carnarvon, Western
Australia. The Carnarvon earth station was built as a result
of an agreement between 14 countries to establish a global
satellite-based communications system by 1968.
ATV0 (now TEN) produced the first colour TV program
The Panasonic Orbitel, model TR-005 was advertised as
‘straight from the Space Age’. With a five-inch screen.
tuning was via a single knob, from VHF to UHF.
siliconchip.com.au
the Middle East and western Asia, opened at Ceduna
in South Australia and Carnarvon established a second
antenna. The Carnarvon station was critical in providing
communications for the NASA’s Apollo manned space
mission program, leading to an astronaut on the moon in
July 1969.
Multipurpose hammer!
“That’s one small step for man, one giant leap for mankind”:
Neil Armstrong’s first step on the moon, the grainy images
watched by millions live on TV in July, 1969.
on Australian television when it televised the Pakenham
Races in colour on June 15, 1967.
Australia took part in two global satellite telecasts. “Our
World”, a two-hour telecast screened simultaneously in
30 countries, with segments produced in 18 countries
including Australia, and a live telecast from Expo 67 in
Montreal.
This Day Tonight commenced on the ABC in 1967 and
was flown all over the country from the Sydney base. This
situation did not last long, as soon better technology was
available.
OTC (the Overseas Telecommunications Commission)
opened their earth station at Moree in 1968, the first
regularly available television relay service. One of the first
presentations was an announcement by President Johnson
that he would not be seeking re-election.
By this time, the ABC had set up microwave links between Sydney and Melbourne and its regional stations in
the country. The ABC, however, rarely used these links for
anything other than sports, a field they dominated.
A second earth station linking Australia with Japan,
the western Pacific, and the US opened at Moree, NSW
in March 1968.
Neil Armstrong placed the first human footprint for
live television from the moon. Most who saw the live,
noisy pictures can remember exactly where they were
at the time.
Australians watched enthralled as the astronauts carried out their activities and televised the wonder of the
alien landscape. Suddenly, screens worldwide went black.
Houston Control checked all links and frantically searched
for solutions to restore the historic footage for an audience
of billions.
They were nearly certain the technical problem was on
the moon. Suddenly live pictures reappeared. Houston
asked the astronaut what he had done. The reply, ‘I hit the
camera with my (prospecting) hammer!’
GTV9’s coverage entered the record books as the longest
continuous live broadcast on television.
While the OTC was highly instrumental in the television
transmission of the lunar landing and associated communications, the plug was pulled on the Australia/England
HF (high frequency) link between London and Melbourne,
after continuous service since 1927.
Now stations could broadcast live news daily from
London via the newly opened Satellite Communications
Earth Station at Ceduna.
Darwin finally joined the television era, the last capital
to commence television broadcasts, in 1971.
Big is beautiful
Early Australian television design was inspired by
American sets with elaborate closing cabinets, though our
designs were less ornate.
Premier models of Australian sets were finished in
beautiful highly-polished laminated wood. Compared to
other countries, Australians had a much greater interest
A globe-trotting Kangaroo.
“Skippy” commenced in 1968, growing to viewing in
128 countries around the world.
Australia became connected, as a second earth
station linked Australia with Japan, the western
Pacific and the US, from Moree. A third,
the link to Britain, Europe, Africa,
Kriesler’s 1968 Multisonic 3-in-1, shown here not just
because it was a great performer, more so because of that strange “thing”
on top. It’s a 3-function wired remote control. Channel changing
was one direction only! (Reproduced larger at left.)
siliconchip.com.au
August 2006 31
in monster three-in-one entertainment
centres, with radio, television and hifi
in one package.
Rather than an ingenious integration of components, many featured a
current model TV, placed in the same
cabinet as a radiogram but with little
or no interconnection.
In fact, the 25-inch TV in Kriesler’s
1968 Multi-Sonic TV Theatre (pictured overleaf ) was totally independent of the radio and record-player,
with a small loudspeaker of its own.
The speaker complement included
eight-inch woofers and electrostatic
tweeters.
By radiogram standards of the time,
the ceramic pickup head, valve amplification and electrostatic tweeters
represented the peak of domestic valve
design quality, with a sweet, crisp
sound. Only top-end audiophile valve
equipment was superior.
Kriesler included servicemanfriendly ideas, like a circuit of the
radiogram attached to the rear, the TV
circuit inside the unit and even printed
directions on the rear cover to guide
on its removal.
No expense was spared, packing in
so much heavy technology and quality
wood finishes, these monsters needed
two strong men to lift for delivery.
Luxury at a price
Noel Gibson joined Gainsborough
Furniture, manufacturers of fine
furniture in 1971. Radio, TV and
radiogram manufacturers relied on
leading furniture companies to build
their cabinets.
Gainsborough furniture moved to
the Astor/Electronic Industries ‘Radio
City’ complex in Clayton, producing fine TV and Radiogram cabinets,
along with domestic furniture, plus
Travelodge hotel furniture. Total
production included fabricating and
welding steel, plus chrome baths, for
metal components used in the furniture production.
Cabinets for Astor receivers were
manufactured entirely in-house at
Gainsborough, from the slicing of raw
wood for laminated veneers, through
to completed cabinets. Stunning wood
veneers included the now virtually
extinct Russian burl walnut. Only
very old Russian walnut trees from a
cold climate but with little frost could
be sliced to exhibit the awesome patterns prized by furniture-makers and
customers.
After laminating, the cabinets were
finished in incredibly hard polyester, buffed to a very high gloss in a
massive buff. Polyester high-gloss
finish was sprayed onto furniture in
a ‘wet booth’. Polyester is the result
of a combined A and B catalyst, later
found to be highly carcinogenic, so it
was replaced by polyurethane. Unfortunately most of the applicators later
died, due to the carcinogenic effects
of the chemicals.
After application, huge European
men – specifically chosen for the
job – rested enormous three in one
cabinets on their bellies, pushing
against a metre-wide buff wheel. Few
finishes before or after compare to the
depth, gloss, lustre and resilience of
this finish.
Plating onto plastic was a new
technique employed by Astor in another plant, to feature on fascias and
knobs, converting them into dazzling
chrome or gilt.
For a time, Gainsborough also made
TV cabinets for other companies, like
PYE and HMV. Noel recalls when
Philips took over, they bought European ideas, ten years ahead of local
production. Soon Philips made TVs
in vinyl-finished plastic cases, with
wrap-around curved style. As vinyl
was a print, almost any wood appearance or pattern was possible.
By the mid-seventies, production was upgraded by Philips, with
machines to do the work of three or
four men.
You are naughty
The Seventies was a radical period
and this was also reflected on the
nations TV screens. Leading the way
in Australian TV’s loss of innocence
were racy soap opera dramas Number
96, The Box and the cult hit comedydrama Alvin Purple. By 1973, Number
96 was the most popular program on
Australian TV, with The Box running
second in 1974.
Classic TV shows started their run
in 1971. Matlock Police from Crawford
Productions, broadcast for five years
on 0-10, Young Talent Time started an
18-year series on the 0-10 Network,
Hey, Hey It’s Saturday was a Saturday
morning cartoon show on GTV9 and
A Current Affair with Mike Willesee,
premiered on Nine.
Beauty and technology
Visitors to Victoria’s bayside areas in the 70s enjoyed television and radio beach
broadcasts, so people could leave the water and enjoy a free live-show, see the
live radio set-up, then later see highlights on TV.
32 Silicon Chip
Visitors to Victoria’s bayside areas
in the 70s enjoyed television and radio
beach broadcasts, so people could
leave the water and enjoy a free liveshow, see the live radio set-up, then
later see highlights on TV. Activities
and competitions were presented on a
large stage, which was moved around
the most popular beach areas.
Channel 9 and radio station 3AK
each presented different programs.
3AK playing popular music and GTV9
siliconchip.com.au
recording the events to present in the
evening news. The highlight was the
Miss Victorian Beach Girl quest.
3AK’s equipment was housed in
a rather makeshift custom audio
console, with modest domestic tape
recorders, basic by today’s standards,
but it did the job.
Well-known television presenters
and judges included Rosemary Margan and ‘baby’ John Burgess. Blind
60’s rock singer and radio announcer
Grantley Dee was in the line-up for
the 3AK broadcasts.
In 1974, Sydney Harbour Bridge
rigger Paul Hogan, becomes a comedy
star and “Countdown”, while ‘Molly’
Meldrum starts a 12-year run on ABC.
Colour our world
Only the first broadcast of television
can compare to the first broadcast of
regular colour programmes, on March
1, 1975. Channel Nine launched “The
Don Lane Show” resulting in an eight
year run. TEN10 launched the first
one-hour news service – “Eyewitness
News” hour. An infamous ‘bombblast’ episode of Number 96 wiped
out four regular characters in a bid
to reinstate top rating position and
Graham Kennedy made a ‘faaark,
faaark’ crow call while Rosemary
Margan read a live advertisement on
“The Graham Kennedy Show”. The
ensuing row forced Kennedy from
the network.
AWA manufactured monochrome
televisions at their Ashfield site until
the introduction of colour, when they
moved to a new facility at the AWV factory Rydalmere near Parramatta NSW.
Australian production and thousands of jobs were forced out of the
market after the government slashed
tariffs in 1976, rather than a long,
gradual phase out.
The future is here
Television is now changing at a
frenetic pace. In 2005, Sony made
their last CRT and posted profit losses,
while electronic equipment these
days usually displays the ‘made in
China’ label.
Where will television and video
technology advance in the next decade? Only the brave would predict.
Who would have anticipated the demise of the VCR for DVD players that
do not record?
The first attempt, Laservision, was
rejected by the public. Then a smaller
DVD disc made VCRs dinosaurs and
new higher-capacity discs are about
to become popular. Whatever the future holds, the pioneers of black and
white television paved the way for
tomorrow’s exciting (and expensive)
large screen colour entertainment
experiences.
SC
Credits and references are shown at:
www.aaa1.biz/sc.html
A young Pete Smith in Studio 9 sound booth. Pete is still doing voiceovers for
Channel 9.
siliconchip.com.au
August 2006 33
SILICON
CHIP
If you are seeing a blank page here, it is
more than likely that it contained advertising
which is now out of date and the advertiser
has requested that the page be removed to
prevent misunderstandings.
Please feel free to visit the advertiser’s website:
dicksmith.com.au
SILICON
CHIP
If you are seeing a blank page here, it is
more than likely that it contained advertising
which is now out of date and the advertiser
has requested that the page be removed to
prevent misunderstandings.
Please feel free to visit the advertiser’s website:
dicksmith.com.au
SILICON
CHIP
If you are seeing a blank page here, it is
more than likely that it contained advertising
which is now out of date and the advertiser
has requested that the page be removed to
prevent misunderstandings.
Please feel free to visit the advertiser’s website:
dicksmith.com.au
SILICON
CHIP
If you are seeing a blank page here, it is
more than likely that it contained advertising
which is now out of date and the advertiser
has requested that the page be removed to
prevent misunderstandings.
Please feel free to visit the advertiser’s website:
dicksmith.com.au
SILICON
CHIP
If you are seeing a blank page here, it is
more than likely that it contained advertising
which is now out of date and the advertiser
has requested that the page be removed to
prevent misunderstandings.
Please feel free to visit the advertiser’s website:
dicksmith.com.au
SILICON
CHIP
If you are seeing a blank page here, it is
more than likely that it contained advertising
which is now out of date and the advertiser
has requested that the page be removed to
prevent misunderstandings.
Please feel free to visit the advertiser’s website:
dicksmith.com.au
Amaze your friends
with this highly
visible animated
clock project.
It’s based on
a PICAXE
micro, a
quartz clock
movement
and a large
quantity
of low-cost
diodes and
LEDs. The
results will
surprise you!
Program & circuit design: RON RUSSO
Article & PC board design: CLIVE SEAGER
Clive Seager is Technical Director of Revolution Education
Ltd, the developers of the PICAXE system.
Novel PICAXE
LED Chaser Clock
I
T’S ALWAYS INTERESTING to see
the many and varied projects that
people create using PICAXE chips.
When first introduced to this LED
Chaser Clock from Ron Russo, I was at
first taken aback with the complexity
of the prototype; how could it possibly
have been made by hand? It was intricately assembled by wiring and soldering together well over 200 components,
all without a PC board!
As Ron himself stated, “the wiring
is kept to a minimum by the strategic
40 Silicon Chip
(piggy-back) placement of the shift registers and the unique way I coupled the
two banks of registers with the isolation diodes. The results of this method
appear more like a work of art than a
rats nest, which is the usual outcome
when no circuit board is used.”
However, most of us would not have
a steady enough hand or the patience
to build such a masterpiece. Therefore,
this incarnation of the project does
include a PC board so that everyone
has a chance to build it!
As can be seen from the photos, the
Chaser Clock is a marriage between an
analog quartz clock movement and a
circular array of LEDs. A continuous
visual display is created by synchronising LED effects with the movement
of the clock’s seconds hand.
Once every second, a “chaser” LED
starts from the 12 o’clock position
and appears to move around the dial
in an anticlockwise direction towards
the seconds hand. When it meets
the seconds hand, the LED appears
siliconchip.com.au
to “freeze” under the pointer (ie, it
remains illuminated).
So at each tick of the clock, one
more LED is illuminated. This creates
an arc of light that trails the seconds
hand. When the seconds hand reaches
12 o’clock, the arc closes to form a
complete circle of light, whereupon
all LEDs are turned off and the cycle
repeats over.
It’s difficult to visualise this effect
simply by reading about it, so we’ve
posted a short video of Ron’s prototype
clock in action on the SILICON CHIP
website. You’ll find it in the downloads section for this month.
Circuit basics
The complete circuit diagram for
the chaser clock appears in Fig.1.
A PICAXE-08 microcontroller (IC1)
drives the whole show with the aid
of timing pulses from the analog clock
mechanism.
The clock is used intact, with a pair
of diodes steering the pulses from its
coil to input3 of the micro. A 2.5V
supply for the clock mechanism is
derived from the 5V rail by dividing it
down with two 330W resistors, while
a 100mF capacitor supplies peak coil
current.
All 60 LEDs are driven by 74LS164
8-bit shift registers. Every tick of the
clock, the PICAXE-08 program performs a few simple calculations and
then manipulates the data (A&B), clock
(CLK) and clear (CLR) inputs of the
shift registers to produce the magical
effects mentioned earlier.
The 74LS164 shift registers are divided into two paralleled banks, with
isolation between the banks provided
in the form of series-connected diodes.
Registers SR1-SR8 handle the LED
chase effect, while SR9-SR16 handle
the arc of light that follows the seconds hand.
With this circuit arrangement, about
10-15mA of current flows through each
LED. No separate current-limiting
resistors are required, which greatly
simplifies the assembly task. Some
might be wondering how this simple
scheme is possible; don’t we always
need to limit LED current in a logicdriven circuit?
The answer is usually yes, of
course. However, by design, the 74LS
series TTL logic devices incorporate
a certain resistance in the upper NPN
output transistor’s collector circuit
(see Fig.3). In the case of the 74LS164,
siliconchip.com.au
this amounts to about 120W.
Accounting for the impedance of the
NPN output and the forward voltage
drop of the LEDs and series diodes,
the total current sourced from each
output shouldn’t exceed about 15mA.
This works very well, with the total
power dissipation for each IC remaining within safe limits.
Note that current will vary between
different brands of LEDs and shift registers, so for best results use devices
from the same manufacturer throughout. Do not be tempted to substitute
devices from another logic family.
For example, while 74HC164 devices
are pin compatible with the 74LS164,
they have an entirely different output
structure and will self-destruct in this
circuit!
Power supply
Due mainly to the large number of
LEDs, overall current consumption is
quite high, starting at about 200mA
and increasing to over 900mA as the
arc of light grows. The original circuit
was developed using an on-board
7805 regulator with a 9V supply but
when using this setup the regulator
gets very hot. Although a sizeable
heatsink would keep the regulator
within operating parameters, there is
still the possibility of heat damage to
surrounding materials.
The final version of the clock was
therefore developed for use with an
off-board regulated 5V power sup-
Par t s Lis t
1 PC board
1 2-way 5mm pitch terminal
block
1 miniature tactile push-button
switch (S1)
1 8-pin IC socket
16 14-pin IC sockets
1 analog clock mechanism (see
text)
Semiconductors
1 PICAXE-08 (IC1)
16 74LS164 8-bit shift registers
(SR1-SR16)
1 1N5817 (or 1N5819) Schottky
diode (D1)
2 BAT85 (or 1N5711) Schottky
diodes (D2 & D3)
120 1N4148 small-signal diodes
(D4-D123)
12 5mm yellow LEDs
48 5mm green LEDs
Capacitors
5 100mF 16V
8 100nF polyester
Resistors (0.25W 5%)
1 2.2kW
1 470W
2 330W
Also required (not in kit)
5V DC 1A (minimum) regulated
power supply (eg, Altronics
Cat.M 8909)
The kit includes two quartz
clock mechanisms like the
one shown here. These are
widely available for just a few
dollars. If you want to use
a dark clock face design,
you can paint the black
hands a lighter colour
(eg, yellow) to obtain a
good contrast.
August 2006 41
Fig.1: here’s the (almost) complete circuit diagram for the clock. As noted, we’ve left out some portions to make it
easier to follow. A PICAXE micro (IC1) manipulates 16 shift registers to control the light show, using pulses from the
clock mechanism for timing. Clever arrangement of the shift registers and LEDs allows the use of the smallest PICAXE
device in the range, with the program code consuming only 76 bytes!
ply, such as the Altronics M-8909.
However, if you prefer to build your
own regulated power supply, you’ll
find a suitable circuit in Fig.4. Note
that any supply should be located no
more than 2m from the clock and the
power leads should be formed from
heavy-duty hookup wire.
42 Silicon Chip
Power is connected to the board via
a 2-way screw-terminal block. A diode
in series with the positive input (D1)
is included for protection against accidental reversal of the leads. We’ve
specified a 1N5817 Schottky diode to
minimise voltage losses, so you should
get a reading of close to 4.7V when
measuring between the +5V and GND
rails on the PC board.
Putting it together
Assembly is very straightforward,
but time consuming! The PC board
is a double-sided design (tracks on
both sides), so take care that you have
siliconchip.com.au
the board the right way up. All of the
components except the LEDs mount
on side with the white silk screen
overlay!
Put all of the LEDs aside for the moment and begin by fitting the diodes
and resistors. Take care to insert each
diode around the right way; the cathode (banded) ends must go in as shown
on the overlay diagram (Fig.2). Also,
don’t mix up the 1N4148 and BAT85
types, which may look very similar
depending on the brand supplied.
siliconchip.com.au
Add all the IC sockets next, orienting the notched (pin 1) end as indicated. Follow with the few remaining components, including the reset
switch, terminal block and capacitors.
Note that the electrolytic capacitors
are polarised devices and must be
installed with their positive leads
oriented as shown.
The final task is to install all of
the LEDs. As shown on the overlay
diagram (Fig.2), there are two possible positions for the LEDs. Most
constructors will probably go for the
outer circle but some clock designs
may suit the inner circle. Don’t install
LEDs in both positions.
Before soldering the LEDs, work out
carefully what your clock face design
is going to look like and how it is going
to fit to the PC board – you may wish to
mount the LEDs several millimeters off
the PC board. Whatever your design,
remember that the LEDs are fitted on
the reverse side of the PC board to all
the other components!
August 2006 43
With all the LEDs in place, plug
the 74LS164 shift registers into their
sockets. It’s very important that the
notched end of each IC lines up with
the notch in its socket.
Clock mechanism
This view shows the fully-assembled clock prototype. Note that there have
been some changes to the PC board since this photo was taken – just follow
the parts layout diagram of Fig.2.
The final task is to “hack” the
clock mechanism. This requires a
steady hand and lots of patience!
The aim is to solder four wires to
the clock PC board; one to each
coil end and two to the battery
connection points.
Start by holding the assembly over a tray to catch any
gears that may drop out. Use a
flat screwdriver blade to carefully open the clock’s plastic
case by sliding it under the
tabs on either side of the casing.
Don’t bend the plastic too far or
it will snap!
You then have to remove the
gears to get access to the coil and its
small PC board. It’s a good idea to take
notes as you remove each piece, as
you have to rebuild the gearbox later!
Before lifting out the circuit board,
study the assembly carefully to see
how the two battery connector strips
make contact with the PC board. Make
a note of which PC board pad connects
to the positive side of the battery.
Lift out the PC board complete with
its plastic surround. You will see two
+
–
Start by removing the
back half of the clock’s
casing. This can be
achieved by sliding a flat-bladed
screwdriver under the tabs on
either side of the casing. Don’t bend
the plastic tabs too far or they will
snap!
44 Silicon Chip
After removing
several of the nylon
gears, you’ll be able to
lift out the complete
coil assembly. Solder
light-gauge wires to the
coil and battery pads on the PC board,
positioned as shown here. Make a
note of which wire goes where – so
that you’ll be able to hook them up
correctly once it’s reassembled.
Remove all of the gears and the two
battery contacts from the case half.
Cut a slot roughly as shown to allow
the four wires to pass out of case
once it is closed, then reassemble the
lot in reverse order. Don’t force the
case halves together – it you feel any
significant resistance, then a gear has
most likely jumped out of position!
siliconchip.com.au
Fig.2: follow this diagram and the legend on the board when assembling your clock. Don’t mix up the different types
of diodes and take care with the orientation of the ICs, diodes, LEDs and 100mF capacitors.
Table 1: Resistor Colour Codes
o
o
o
o
siliconchip.com.au
No.
1
1
2
Value
2.2kW
470W
330W
4-Band Code (1%)
red red red brown
yellow violet brown brown
orange orange brown brown
5-Band Code (1%)
red red black brown brown
yellow violet black black brown
orange orange black black brown
August 2006 45
Program Listing: PICAXE Clock
symbol Sec = b13
symbol Leds = b12
symbol TmLength = w0
symbol ChaseClock = 0
symbol NewSec = 1
symbol NewMin = 2
symbol ChaseData = 4
'seconds counter
'chase counter
'duration of pulsout to match chase with second
'pin0
'pin1
'pin2
'pin4 (chase data output & reset input for sync)
MAIN:
pause 100
high NewMin
goto RES_MIN
'settling time
'release SR9-SR16 reset (MR) inputs
'go initilise for start of new minute
LOOP:
input 4
if input4 = 1 then RES_MIN
if input3 = 1 then NXT_SEC
'set pin 4 as input
'if sync button is pressed initialise for new minute
'else a high-going pulse on input 3 indicates one second has elapsed,
'so start a new second
' NOTE: Some analog clocks have low-going rather than high-going pulses (change the above line to suit).
goto LOOP
NXT_SEC:
output 4
if Sec = 0 then RES_MIN
Sec = Sec – 1
'loop until a clock pulse occurs
'set pin4 to output to send chase data
'if min is up then go reset minute
'else one sec has elapsed so decrement secs
' Calculate optimum time factor so that all intended LEDs are illuminated just before the current
' second is up. A multiplication factor of 90 is optimum for the PICAXE-08.
TmLength = 61 – Sec
TmLength = TmLength * 90
CHASE:
high ChaseData
'set chase data bit high
for Leds = Sec To 0 Step –1
'count back starting from relevent second
pulsout ChaseClock, TmLength 'pulse with calculated duration to increment clock input of chase
'regs(SR1-SR8).
low ChaseData
'after first clock pulse, set data low for rest of chase
next Leds
'do rest of LEDs until this sec finished
low NewSec
pause 1
high NewSec
goto LOOP
RES_MIN:
Sec = 60
low NewMin
pause 1
high NewMin
Fig.3: the equivalent circuit
for each output (O0-O7) of a
74LS164 shift register. The
resistance in the collector leg of
the high-side transistor greatly
reduces the maximum current
that these devices can source.
'zero SR1-SR8 outputs, clock SR9-SR16
'make pulse 1ms wide
'return high
very fine wires connecting the coil to
two small pads near the edge of the
PC board. These are only as thick as a
human hair, so you may need a bright
light and a magnifying glass!
Now carefully solder two light-gauge
hookup wires (about 150mm long) to
the coil connection pads. Study the
orientation and dress of the wires in
the photos before you begin.
The kit for this project includes two
PP3 battery snaps that can be sacrificed
for their black and red wires. Simply
cut off the battery snaps and use the
pre-tinned wire ends for the clock connections. Alternatively, you could use
rainbow cable for the job.
Only hold the soldering iron in
'power up or minute is up or syncro reset . . .
'reset all SR9-SR16 outputs to zero
'make pulse 1ms wide
' As the first 4 outputs of SR9 are not connected to LEDs we must send a dummy run of 4 clock
' pulses to shift regs SR9-SR16 to start at LED60 (SR9 output O4). This will also pulse the reset (MR)
' inputs of SR1-SR8, zeroing their outputs ready for the new minute.
for B10 = 1 to 4
pulsout NewSec, 10
next
if input4 = 1 then LOOP
goto NXT_SEC
46 Silicon Chip
'check input again if sync button still pressed
'else go start a new minute
Ron Russo’s prototype was made by
hand wiring over 200 components –
all without a PC board. The ICs were
even piggy-backed!
siliconchip.com.au
place for a fraction of a second – if a
joint is overheated the pad will lift off
or the coil wire come adrift. Next, solder the two power wires. Thankfully,
these are easier to work with, as the
pads are much larger. Be sure to note
the positive (+) and negative (-) wires
for later identification.
Important: it is not necessary to
remove the coil and its PC board from
the plastic surround. However, you
must be very careful not to contact
the gear posts that are part of the
plastic molding with the barrel of your
soldering iron!
Remove the two metal battery contact springs from the plastic casing and
use a sharp knife to cut a small opening
in the plastic to allow the four wires
to pass through (see photos).
You can now reassemble your
clock mechanism, with the aim obviously being to get all of the gears in
the right places! Finally, mount the
clock to the chaser PC board and
solder the four wires in position.
Fit the hands and then you’re
ready to go!
Made a mistake during the
assembly or lost a gear? Don’t
worry; the kit includes a spare
clock mechanism!
Fig.4: the clock must
be powered from a
regulated 5V DC supply
with at least a 1A
capacity. High-power
regulated plugpacks are
readily available but
if you want to use an
unregulated plugpack,
you’ll need to add a 5V
regulator circuit. Here’s
a suitable circuit based
on the popular 7805.
PICAXE program
The PICAXE chip in the kit
is supplied pre-programmed
with Ron’s original program.
However, the fully commented
listing is included here for those
who wish to experiment. In particular, the timing multiple (90)
may need tweaking slightly if your
chaser runs too fast or too slow.
A programming socket is not included on the PC board. However, it’s
a simple matter to reprogram the micro
in any of a number of different project
boards. If you don’t already have a
suitable board and programming cable,
check out the Schools Experimenter
Starter Pack (part. no. AXE092S) or
the PICAXE-08 Starter Pack (part no.
AXE-003). Both are available from
MicroZed Computers; see the adjacent
panel for contact details.
Synchronisation to the seconds
hand is achieved by pressing the
reset button and then waiting for the
seconds hand to reach 60. The LED
display will be blanked and then start
from 1 when the button is released.
The clock will stay in sync until power
SC
is removed.
siliconchip.com.au
This side of the board looks very bland without the clock face. You don’t
get one of these in the kit but you can easily create your own from a
favourite photograph or desktop wallpaper (we used “The Matrix” theme
wallpaper). The numerals can be added in just about any graphics program
and the result printed out on photographic quality stock.
Where To Buy A Kit Of Parts
The PC board copyright for this project is owned by Revolution Education
Ltd. Complete kits (part no. AXE115S) are available from authorized PICAXE
distributors – see www.microzed.com.au or phone MicroZed on 1300 735
420. Note: kit does not include clock face (see above).
August 2006 47
Re s u r r ec t y our o l d L P s an d 7 8 s . . .
Build this magnetic
cartridge preamplifier
an d d u b t h em on t o CD s or MP 3 f ile s
Do you have an old turntable but no RIAA
inputs on your preamplifier? If so, you
need this preamplifier for playback and for
converting them to CD or MP3 format.
By JOHN CLARKE
D
O YOU HAVE a collection of old
vinyl or 78 RPM records languishing in a cupboard? Perhaps you
should resurrect them before they
deteriorate further. To do this you need
a computer with a CD or DVD burner,
suitable software and a preamplifier.
The preamplifier described here can be
built to suit vinyl or 78 records and is
self-contained. You can build it into a
48 Silicon Chip
diecast metal case or underneath your
turntable.
Of course some people will just
want to listen to their records, without
the bother of feeding signals into a
computer and so on. This preamplifier
will suit those people too but ultimately, we think that anyone who has
become used to the high-quality sound
of compact discs or MP3 players will
be disappointed with the clicks and
pops and surface noise on LPs and 78s.
So by all means build the preamplifier
to play your old records but you will
probably end up going the whole way
and dubbing your records to CD. In the
process, you can filter out most of the
clicks and noise and once again enjoy
those old favourites.
If you only have vinyl records (LPs)
you can build this project as a standard
preamplifier with RIAA equalisation
but if you want to play 78s, you will
need to choose one of three equalisation curves which can also be built
in. You will also need a turntable that
can play at 78 RPM and a cartridge
that accepts the correct stylus (more
details on this in our feature article on
transferring LPs to CD next month).
siliconchip.com.au
Fig.1: the preamplifier circuit is based on two LM833 dual op amps (one channel only shown). It includes three sets
of feedback networks (R1-R3 & C1-C2) and the values are chosen to give the equalisation required (see tables).
Ideally, the turntable should have a
speed adjustment so that the pitch can
be changed but this is a rare feature.
Alternatively, commonly available
recording software can adjust the pitch
when you dub the records to CD.
The SILICON CHIP RIAA Preamplifier
is housed in a diecast box and has
RCA sockets for the input and output
connections. It has a control to set the
output level and is powered using an
AC plugpack.
By the way, this preamplifier supersedes the preamplifiers described in
March 2002 and April 1994.
in Fig.1. This shows the left channel
only; the right channel is identical.
Some readers may wonder why we
have used LM833 dual op amps instead of the newer high-performance
OPA2134 devices featured in our recent Studio Series Preamplifier. In fact,
they could be used but since the signal
source is a magnetic cartridge playing vinyl or 78 RPM shellac records,
any slight performance improvement
will be negligible and unable to be
discerned by listening.
The input signal is fed through in-
Specifications
Signal-to-noise ratio: -84dB unweighted with respect to 10mV in and
560mV out (-89dB A-weighted)
Total harmonic distortion at 1kHz 10mV in and 560mV out: 0.014%
Crosstalk: -79dB at 100Hz, -80dB at 1kHz and -70dB at 10kHz
Circuit description
Signal handling: 140mV before clipping
The preamp circuitry is based on
two LM833 dual op amp ICs, as shown
RIAA accuracy: typically within 1dB from 20Hz to 20kHz (see graph)
siliconchip.com.au
August 2006 49
Par t s Lis t
1 PC board, code 01108061,
102 x 81mm
1 blank PC board, 70 x 30mm
1 diecast box, 119 x 94 x 57mm
1 12VAC 250mA plugpack
1 SPST slimline toggle switch (S1)
2 dual RCA PC-mount sockets
1 5-pin DIN PC-mount socket
(optional)
1 2.5mm PC-mount DC socket
1 16mm dual 10kW log PC-mount
pot (VR1)
2 crimp eyelets
1 green banana socket
6 2-way 2.5mm pin headers
(from a 12-way header strip)
2 2.5mm jumper plugs
2 ferrite beads 4mm OD x
1.5mm ID x 5mm (L1,L2)
4 10mm M3 tapped spacers
4 adhesive rubber feet
4 M3 x 6mm screws
2 M3 x 10mm screws
2 M3 nuts and star washers
2 No.8 self-tapping screws
7 PC stakes
1 150mm length of green hookup wire
1 150mm length of red hook-up
wire
1 150mm length of 0.7mm tinned
copper wire
Semiconductors
2 LM833 dual op amps (IC1,IC2)
1 7812 12V regulator (REG1)
1 7912 -12V regulator (REG2)
2 1N4004 1A diodes (D1,D2)
1 5mm red LED (LED1)
Capacitors
2 1000mF 35V PC electrolytic
6 47mF NP or BP non-polarised
electrolytic
1 10mF 35V PC electrolytic
2 10mF 16V PC electrolytic
2 1mF NP or BP non polarised
electrolytic
2 560pF ceramic
2 100pF ceramic
Resistors (0.25W 1%)
2 47kW
4 150W
2 7.5kW
1 39W
4 1kW
RIAA components
2 200kW resistors
2 16kW resistors
2 15nF capacitors
2 4.7nF capacitors
50 Silicon Chip
Fig.2: the RIAA response curve. The bass and treble turnover frequencies are
set by the RC components in the feedback network connected to IC1a in the
preamplifier.
ductor L1, a 150W resistor and a 47mF
capacitor to pin 3 of IC1. The 47kW
resistor and 100pF capacitor provide
the loading for a typical magnetic
cartridge. As well, the 100pF capacitor functions as an RF input filter, in
conjunction with inductor L1 and the
150W resistor.
IC1a’s gain is set by the feedback
components between pin 1, pin 2
and ground. The 1kW resistor and
47mF non-polarised capacitor set the
low-frequency roll-off for this stage at
around 3Hz.
We have shown three sets of feedback components (C1, C2, R1, R2 &
R3) and these can be selected to provide the RIAA or other equalisation
responses for older recordings. The
three sets of feedback components are
labelled SET1, SET2 and SET3 and the
particular equalisation SET is selected
using jumper plug LK1, LK2 or LK3.
The feedback components for the various equalisation curves are shown in
Tables 2 & 4.
High-pass filter
IC1a’s output appears at pin 1 and
is fed to pin 3 of IC2a via a high-pass
filter comprising a 1mF capacitor and
a 7.5kW resistor. This filter rolls off
Why So Many Choices For Equalisation?
Readers may be surprised to see all the various equalisation curves for
vinyl (45 & LP) and 78 RPM records. It is not well-known these days that
before the recording industry standardised on the RIAA curves, the bigger
recording companies had their own equalisation curves, hence there were
curves such as Decca’s ffrr (it stood for “full frequency range recording”),
EMI, NARTB and Columbia.
The situation was even more chaotic before vinyl LPs came on the scene
and there was more choice (and confusion) with 78 records. Hence, some of
the equalisation curves used included Decca (EMI) 78, Westrex and so on.
The reason for including these different sets of components in Tables 2 &
4 is so that if you can identify the company that made a particular recording,
you can then select the appropriate equalisation characteristic.
Note that we have also shown values for flat frequency response (ie, no
equalisation) and tape head equalisation.
siliconchip.com.au
Table 1: Microgroove 45 & LP Frequencies
Curve
Treble
Turnover
Bass
Turnover
Lower Bass
Turnover
Cut at 10kHz Boost at 50Hz
RIAA
2.1215kHz
500Hz
50.5Hz
-13.6dB
17dB
ffrr LP
3kHz
500Hz
100Hz
-10.5dB
12.5dB
EMI LP
2.5kHz
500Hz
70Hz
-12dB
14.5dB
NARTB
1.6kHz
500Hz
–
-16dB
16dB
Columbia
1.59kHz
500Hz
100Hz
-16dB
12.5dB
Table 2: Components For Microgroove 45s & LPs
Curve
R1
R2
C1
C2
R3
RIAA
16kW
200kW
4.7nF
15nF
–
ffrr LP
220kW
18kW
15nF
3.3nF
270kW
EMI LP
330kW
18kW
15nF
3.9nF
270kW
NARTB
2.2nF
18kW
18nF
5.6nF//390pF
270kW
Columbia
100kW
18kW
18nF//2.2nF 5.6nF//390pF
270kW
Table 3: Coarse Groove 78 Frequencies
Treble
Turnover
Bass
Turnover
Decca 78
3.4kHz
150Hz
–
-9dB
11dB
ffrr 78
6.36kHz
250Hz
40Hz
-5dB
12dB
Westrex
Flat
200Hz
–
–
15dB
Blumlein
Flat
250Hz
50Hz
–
12dB
BSI 78
3.18kHz
353Hz
50Hz
-10.5dB
14dB
Curve
Lower Bass
Turnover
Cut at 10kHz Boost at 50Hz
Table 4: Components For Coarse Groove 78s
Curve
R1
R2
C1
C2
R3
Decca 78
open
18kW
68nF
3.3nF
270kW
ffrr 78
220kW
18kW
33nF
1.5nF
270kW
Westrex
18nF
18kW
33nF
–
270kW
Blumlein
220kW
18kW
33nF
–
270kW
BSI 78
220kW
18kW
22nF
3.3nF
270kW
Table 5: Components For A Flat Response
Gain
R1
R2
C1
C2
R3
x1
link
1kW
–
4.7nF
–
x 11
link
10kW
–
470pF
–
x 101
link
100kW
–
47pF
–
Table 6: Components For Tape Head Equalisation
NAB
R1
R2
C1
C2
R3
–
3.6kW
–
15nF
200kW
These tables show the components necessary to achieve the various response
curves required to play back from vinyl records and other recording surfaces,
including Shellac 78s and tape heads. The parts necessary to achieve a flat
response (with various gains) for general-purpose use are also shown.
siliconchip.com.au
August 2006 51
Table 7: Capacitor Codes
Value
68nF
33nF
22nF
18nF
15nF
4.7nF
5.6nF
3.9nF
2.2nF
1.5nF
560pF
470pF
100pF
47pF
μF Code
.068mF
.033mF
.022mF
.018mF
.015mF
.0047mF
.0056mF
.0039mF
.0022mF
.0015mF
NA
NA
NA
NA
EIA Code
683
333
223
183
153
472
562
392
222
152
561
471
101
47
IEC Code
68n
33n
22n
18n
15n
4n7
5n6
3n9
2n2
1n5
560p
470p
100p
47p
Above: this view shows the fully
assembled PC board with all feedback
component sets installed. In practice,
you would normally only install
one feedback set (typically for RIAA
equalisation) and omit the parts for
the other two sets.
The PC board is installed in the case by angling it as shown here, so that
the RCA sockets and the pot shaft go through their respective holes. It then
sits on Nylon spacers that are pre-fastened to the bottom of the case and is
secured using machine M3 x 6mm screws.
52 Silicon Chip
signals below 20Hz to reduce rumble
from the turntable. Signal above 20Hz
is free to pass to the next stage of amplification within IC2a.
The gain of op amp IC2a is adjustable using potentiometer VR1. When
VR1 is set fully anticlockwise, its
resistance is zero and IC2a has a gain
of 1. Conversely, when the wiper is
fully clockwise, VR1’s resistance is
10kW and so the gain is 11. The 560pF
capacitor across VR1 rolls off the gain
at higher frequencies to prevent oscillation.
The outputs from IC2 are fed to the
RCA sockets via 150W resistors, another measure to prevent oscillation
because the of the capacitance of the
screened signal leads.
Power for the circuit comes from a
12VAC plugpack which is fed to two
diodes and two 1000mF capacitors to
produce positive and negative supply
rails. These are fed to 3-terminal regulators to derive ±12V DC rails.
Note that the plugpack feeds the two
diodes via a 39W resistor to limit the
siliconchip.com.au
Fig.3: follow this parts layout and wiring diagram to build the preamplifier. Note that you can select
only one set of feedback components at a time using either links LK1 or LK2 or LK3.
Table 8: Resistor Colour Codes
o
o
o
o
o
o
o
o
o
o
o
o
o
o
No.
1
1
1
2
1
2
1
2
1
2
4
4
1
Value
330kW
270kW
220kW
200kW
100kW
47kW
18kW
16kW
10kW
7.5kW
1kW
150W
39W
peak current into the 1000uF capacitors. This minimises any tendency for
100Hz rectifier buzz to become audible
in the preamp’s output signal.
The case of the preamp may be
earthed should this be necessary to
siliconchip.com.au
4-Band Code (1%)
orange orange yellow brown
red violet yellow brown
red red yellow brown
red black yellow brown
brown black yellow brown
yellow violet orange brown
brown grey orange brown
brown blue orange brown
brown black orange brown
violet green red brown
brown black red brown
brown green brown brown
orange white black brown
avoid mains hum in the signal. In most
cases, this will not be required.
Building the preamplifier
The new preamplifier is built on a
PC board coded 01108061 and measur-
5-Band Code (1%)
orange orange black orange brown
red violet black orange brown
red red black orange brown
red black black orange brown
brown black black orange brown
yellow violet black red brown
brown grey black red brown
brown blue black red brown
brown black black red brown
violet green black brown brown
brown black black brown brown
brown green black black brown
orange white black gold brown
ing 102 x 81mm. It fits into a diecast
box measuring 119 x 94 x 57mm. Fig.2
shows the wiring details.
It’s a good idea to first check the PC
board for any defects such as shorts
between tracks or for any breaks in the
August 2006 53
earth available (eg, an earthed metal
case) to connect to the green banana
socket.
The shield consists of a piece of PC
board 70 x 30mm and is soldered to
the PC stakes in the position shown.
LED1 mounts high on its leads so it
can be bent over and inserted into a
hole in the side of the case.
Case work
The metal case can be earthed (via the
banana socket) if mains hum is a problem.
This usually won’t be necessary, however.
copper areas. Repair these if necessary
and also check that the board has the
correct hole sizes for the components
such as the RCA sockets, DC power
socket and the dual ganged potentiometer.
Now begin the assembly by installing all the links, PC stakes and 2-pin
headers. Before you insert the resistors, decide on the value of components you are going to use for each of
the equalisation sets. In most cases you
would only use one set for the RIAA
equalisation (the others can be left
out). Note that you need to place the
Fig.4: use the 5-pin DIN plug only
if you need an earthed supply. The
Jaycar MP-3022 earthed 17VAC
plugpack can supply the required
AC power and earth.
54 Silicon Chip
same components in both the left and
right channels for each set. Install the
resistors using the colour code table
(Table 8) as a guide to finding the correct values. It’s also a good idea to use
a digital multimeter to make sure they
are correct, as some of the colours can
be difficult to decipher.
The two ferrite beads are mounted
with short lengths of tinned copper
wire passed through them.
The ICs can go in next, taking care
to orient them correctly. Install the
two diodes and the two regulators and
make sure the 7812 and the 7912 types
are placed in the correct positions.
Next up are the capacitors. The
polarised electrolytic types must be
mounted with the correct polarity, as
shown on the overlay. Also, make sure
you use the 35V 10mF capacitor adjacent to IC2. The NP (non-polarised)
or BP (bipolar) electrolytic capacitors
can be inserted either way around.
Use Table 7 as a guide to selecting the
non-electrolytic capacitors.
Next, mount the two RCA sockets,
the potentiometer and the DC socket.
The 5-pin DIN socket can be installed
later if you find that you need an
earthed supply and there’s no mains
The metal case will require drilling
out to accommodate the two stereo
RCA sockets, the potentiometer and
the LED on the front face of the case.
On one side, holes are required for the
earth screw, the power switch and the
DIN socket if used. At the rear, holes
are required for the DC supply socket
and the banana socket.
Mark and drill these holes out. The
slot required for the switch is best
made by drilling about three holes
within the cutout area and then filing
it to shape. Four holes also need to
be drilled in the base for the plastic
spacers for the PC board.
That done, attach the four rubber
feet to the base of the case and then
wire up the switches and earth connections as shown in Fig.3.
Testing
Connect power to the preamplifier
and check that the LED lights when
power is switched on. If it does not
light, then perhaps the LED is installed
the wrong way around.
Next, measure the voltage between
pins 4 & 8 of IC1 and IC2. It should be
close to 24V DC in both cases. If this
is correct, you are ready to connect a
turntable and test the preamplifier.
Select RIAA equalisation for both
the left and right channels using the
jumper links, then connect the RCA
leads from the turntable to the input
sockets on the preamplifier. The RCA
outputs on the preamplifier go to either
a power amplifier or the line input of
a computer using a “Y” lead. The “Y”
lead consists of a shielded stereo lead
with RCA plugs at one end and a stereo
2.5mm jack plug at the other end.
If you are connecting the preamp to
an amplifier, then plug in headphones
or use loudspeakers. If you are playing to a computer, make sure the line
input level is turned up. You can set
this in Windows XP via Start/Settings/
Control Panel/Sounds and Audio Devices/Audio, then selecting Volume in
SC
the Sound Recording section.
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08/06
SERVICEMAN'S LOG
The dreaded black spot disease
Black spots on a plasma display panel aren’t
good at the best of times. This one really had
us scratching our heads for a while but the
explanation turned out to be quite simple.
We had a Philips 42PF9954/68C
Plasma (PDP) using a Fujitsu Hitachi
high-definition display come in with
the owner complaining of black spots.
Sure enough, when we raised it up on
our terrific new Panasonic display rig
trolley – which can raise or lower the
PDP (plasma display panel) to 45° or
flat – you could clearly see lots of tiny
black spots, which were in fact pixel
dropouts.
Pixel dropouts really are no longer
56 Silicon Chip
an issue these days – at least, not until
this set was dropped in. Anyway, we
checked the unit out carefully and
made sure that all the voltages were
correct but could find no reason for
this to have happened. It was then that
we started to notice a few clues that
pointed to possible owner abuse. For
an item as new as this, you wouldn’t
expect to see a lot of scratches around
the mounting screws, plus it was very
dusty and grubby.
Items Covered This Month
•
Philips 42PF9954/68C plasma
TV set (PDP) – FM242 chassis
•
Panasonic TX-80P300A TV
set – EURO 7 chassis
•
•
Funai Technicolor 212E VCR
•
LG Flatron RT-21FA31 (A) TV
set – MC1019A chassis
Panasonic TC68V86A TV set
– MX4M chassis
When we asked the client about this,
he finally admitted that the unit had
been fitted inside a bus and then taken
right around Australia, including the
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LTW
Harsh Environment Connectors
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C-16 Line
Multipin Circular Line
D-Sub Multipin
This is the picture on Mr Diesel’s Panasonic TV set after
replacing the flyback transformer. It looks like an EHT or
picture tube problem but the fault was quite different.
back of “Woop Woop”. Under those circumstances, especially considering the horrendous vibration over all those
corrugated dirt roads and the heat, the set was actually
performing pretty well!
The sick Panasonic
Mr Diesel’s 2001 Panasonic TX-80P300A TV set (EURO
7 chassis) weighed 74kg, so I was delighted when he and
his son carried it all the way onto my workshop bench.
The set appeared to be completely dead but an initial
inspection revealed nothing untoward, with no blown
fuses or burnt components. I then measured the power
coming into the set, tracing it all the way to relay RL801,
before checking for voltages on the solenoid. I was surprised to see there was 7.5V reaching the relay drivers
and in fact, I could toggle the relay using my ohmmeter
as a driver. However, nothing much else was happening
and one of the problems was that the U Board wasn’t
switching the relay on.
At this stage, I had to make up some sort of an estimate
for the repair of this set. Knowing that the U Board (and
DP Board) can give problems (they are the main microprocessor boards for control and sound), it was tempting
to just quote for the U Board and leave it at that. However,
in this case, I would have been wrong.
Being a sensitive individual, I really didn’t want to do
that without being sure and so I borrowed a U Board (with
MPU IC1101 SDA6000) from another set. This substitute
board produced more action, allowing the red standby
LED D1051 to come on and off and the relays to click.
However, there was still no EHT and the set switched
back to Standby.
This set does not lend itself to easy access, so it meant
quite a bit of mechanical surgery to get the D Board
completely out. Using an ohmmeter, I soon found a short
on the 144V rail which was due to the 2SC5591PK line
output transistor (Q551). So far so good but I now had
to find out why this transistor had failed.
I began by checking the tuning capacitors and D558
for leakage but these checks revealed nothing. It was
only after I removed the flyback transformer T551
(ZTM77018A1) and used the shorted turns tester on
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Multipin Circular
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LTW connectors represent the ultimate in value and reliability for
manufacturers of industrial equipment requiring waterproof connectivity.
Available in IP66, 67 & 68 ratings for use in almost any environment.
Altronic Distributors carry a range of products ex stock (see website for range
available). Other LTW models available upon request. Minimum quantities apply.
Sydney Melbourne Perth
DISTRIBUTORS PTY. LTD.
Phone: 1300 780 999
Web: www.altronics.com.au
The Microbric Viper is a perfect entry point into robotics
and programming, or the ideal compliment to your
existing robotics line up!
All modules are fully assembled, meaning there is no need
for a hot soldering iron to build your robot. This makes the
Microbric Viper perfect in an educational environment.
The Microbric connection system means fully reusable
modules can be put together and taken apart quickly.
Microbric requires nothing more than the supplied
screwdriver to assemble, making it possible to have an
operating robot in less than one hour!
The Viper is controlled by a BasicAtom.com microcontroller,
which is programmed in ‘BASIC’, an easy language to learn
the fundamentals of robotics programming.
Remote Control Robot
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August 2006 57
Serviceman’s Log – continued
pins 9 and 10 that I discovered the
real cause – the transformer was up
the spout.
The replacement parts arrived about
a week later and I immediately fitted
them. I then switched the set on, fully
expecting it to be working again and
only requiring some adjustments to
the two focus controls and the screen
potentiometers. Instead, I was horrified to find that not only did I have
great difficulty in switching the set
on (the remote wasn’t working) but
all I could get was a weird picture that
was small and out of focus (see photo).
And no matter what I did, I couldn’t
improve it.
I was beginning to suspect the picture tube and yoke but was once again
saved by having another working set.
Swapping the complete chassis soon
proved that it wasn’t that so I swapped
over the CRT socket board (L) but it
wasn’t that either. I then swapped over
the entire defection D board but again
drew a blank.
By now, I could really feel my frustration level rising. I just couldn’t work
out what could possibly be causing
these symptoms, particularly the lack
of focus. Surely this could only be an
EHT problem? However, I had already
replaced that entire section.
58 Silicon Chip
Well, I persevered, swapping between the two chassis board by board
in an effort to track the fault down. It
wasn’t until I got to the main motherboard (A) that I finally managed to
transfer the fault. None of its modules
made any difference though, including
the U Board.
Well, because of the multitude of
weird symptoms, I opted to replace
the EEPROM IC1104. Bingo! – that was
the cause of all the problems.
IC1104 has ST24LC16B.1A45 written on it and the part number is listed
as 24LC16B1PA45. The only problem
was that the new IC arrived unprogrammed and gave an extremely bright
uncontrollable raster that would probably quickly damage the new flyback
transformer if left on.
Well, what was I supposed to do
now? I ordered an EEPROM read/
writer from Jaycar but there were some
further checks to do before this piece
of equipment arrived. First, I went
through our pile of scrapped TV chassis looking for a Panasonic EEPROM
that was similar to the one required.
Eventually, I found one in what looked
like an MD-1 chassis.
Installing this in my chassis gave a
reasonable picture but with a limited
amount of control. However, I could
at least get into the service menus
and “Self Check” reported only six
errors.
Fortunately, having the service manual helped in setting up the EEPROM
edit mode. As I quickly discovered,
this is somewhat involved. You have
to go into both Service Mode 1 and
Service Mode 2 before entering the
EEPROM Edit Mode.
To do this, you must select Channel
99, set the OFF timer to 15, the Bass to
maximum and the Treble to minimum,
press the “F” button on the TV and
set the volume to zero. The volume
display must be ON while you simultaneously press the Volume Down on
the TV and the Recall or Index button
on the remote.
To get to the next menu you have to
scroll down to the last menu page of
Service Mode 1 (SPL, GAIN) with the
RED remote button and then press the
HOLD key. You then press the RECALL
button on the remote and if the menus
haven’t timed out in the process you
should have arrived at the EAROM
Editor with a large table of addresses
and data.
The OPTION addresses are OE0 to
OE7 and OE8 to OEF and you have to
make sure that the data for each address
is correct for your model in the table
list in the service manual. In my case, I
had five options that needed changing.
You scroll with the coloured keys and
channel up/down on the remote and
change the data value with volume +
and -. When the value is correct, you
have to store it by pressing the STR
button. You then exit the edit mode
by turning the set off.
In my case, I had to re-enter the
menus several more times to get the
geometry and grey scale correct for
this specific set.
It was at this stage that I suddenly
realised that I had lost the sound.
This was caused by dry joints on the
DP Board (TVPA1727ZA) which is no
longer available. The current revision
is V5 which is printed on the edge
of the board. The dry joints involve
IC2510 – a 32 pin dual in-line surfacemounted IC – and a lot of feedthrough
solder connections. This is fiddly detail
work that I find difficult but necessity
is the mother of invention.
Anyway, that finally fixed all Mr
Diesel’s problems but as you can appreciate, a job like this is extremely
difficult to quote for without actually
doing all the work first.
siliconchip.com.au
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Ironically, I found out later that
you can obtain the EEPROM preprogrammed for less money than the
empty one. The correct part number
for the TX-80P300A is TVRJ2A021
which is no longer available but is
substituted with TVRJ2A007 for the
TC-68P22A.
VCR formats
In 1980, the VCR manufacturers
were in a huge mess over which format standard to adopt – VHS, Beta or
VC2000 – and the marketing wars were
on for young and old. Suddenly, a new
contender appeared with the compact
CVC quarter inch (6.25mm) cassette.
This lightweight portable (3.5kg)
player came out of nowhere from a
small company called Funai (F612VE)
and sold for around $1500! It was
marketed around the world under a
variety of different brands and was
sold with a variety of different accessories. The camera option was either
a JVC GX-44E or Hitachi GP-41D and
there was also a TV tuner.
This upstart precipitated a new
round of technology, including the
Video 8 and VHS-C cassettes. The
siliconchip.com.au
CVC cassette format quickly lost out
and you rarely even hear of it now 26
years later.
When a good friend of mine passed
away recently, his family was left with
a complete CVC system, including one
cassette on which a recording had been
made. Hoping that this contained significant video coverage of my friend,
they asked me to copy it onto DVD.
This was going to be no mean feat as
the recorder no longer worked properly. This particular model was called
a Technicolor 212E and the last time
I had seen one of these was well over
15 years ago.
However, I was pleasantly surprised
to discover a copy of the original Funai
service manual buried in our archives.
It had been supplied by Hanimex who
were the local agents at that time.
The recorder is well built and is easy
to disassemble, apart from a couple
of hidden screws on the righthand
side control panel. The deck I was
working on had no reel torque and
consequently was chewing up tapes on
play and stop when the loading motor
unravelled and spilt the tape inside.
Once the deck was out, it didn’t take
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long to discover that the problem was
caused by disintegrating rubber drive
belts – in particular the reel belt which
had broken into several lengths on the
bottom of the unit.
I thought that guessing the size of
this belt would be a problem but was
pleasantly surprised to discover that
I still had the original parts in stock
(“never throw anything out, it might
come in handy” is my motto). However
I wasn’t quite that lucky – my stock belt
was also 26 years old and had also perished. However, it wasn’t too far gone
for me to be able to measure it and order
a generic one the same size.
The other four belts were also ordered at the same time and when they
arrived, I quickly fitted them and reassembled the deck. I then connected a
DVD recorder to the AV outputs on
the power supply and made quite a
reasonable copy. In fact, I was quite
impressed with the performance of
this machine, considering it was built
some 25 years ago.
Recycling an LG
A young lady recently phoned and
asked me to come and pick up her LG
August 2006 59
Serviceman’s Log – continued
at the rear of the set, especially round
the AV sockets.
I suspected that the problem was
an AV switching fault but it was too
hard to fix in a poorly accessible dark
corner in the house. The set had to
go back to the workshop and once on
the bench, I used a CRO to quickly
trace the fault to the AV switching IC
(IC3001, M51321P) on the H Board
where all the AV inputs are. A new
one fixed everything.
Back to school
Flatron RT-21FA31 (A) TV set. This set
uses an MC1019A chassis and the unit
in question was only a few years old.
She didn’t want the set fixed, however. Instead, she wanted me to take it
away and do whatever I wanted with
it. The set was dead and she was recycling it the best way she knew. The
cost of repairing it versus upgrading
the set to an LCD or plasma set made
it redundant.
Well, the set was in good condition
and looked the part. And it didn’t take
me long to determine that it was dead
(or rather pulsating) because the line
output transistor (Q402, TT2140) was
short circuit.
Its replacement is part number
OTR570200AA which can be substituted with a 2SD2627 or KSD5702.
My only concern was what caused its
early demise.
First, I pulled the flyback transformer T401 out and checked for shorted
turns – it measured OK so I figured it
was probably OK. That’s the problem
with a shorted turns tester – it’s not
a conclusive test and often doesn’t
pick up shorts in the EHT overwind
diodes.
Silicon Chip Binders
H Each binder holds up to 12 issues
H SILICON CHIP logo printed on spine
& cover
Price: $A12.95 plus $A5.50 p&p each. Available in Australia only. Buy five and get them
postage free.
60 Silicon Chip
It cost me an extra transistor before
I woke up to the fact that it really did
need a new flyback transformer as well
(Part No. 6174V-6006E). My excuse is
that I was seduced by the dry joints on
the horizontal driver transformer and
(incorrectly as it turned out) blamed
these for the transistor failure.
This fixed the fault but was it really
worth it? The set is now only worth
about $200 new and the trade cost of
the parts alone was about $75, so selling it for about $100 won’t even pay for
my labour, let alone give me a profit.
It’s incredible but perfectly good
technology is destined to become
landfill in less than five years in ever
increasing amounts. How is the planet
going to filter out the dangerous chemicals before we eventually eat and drink
the residue?
The corroded Panasonic
I was called out to a customer’s
home to attend to a supposedly dead
Panasonic TV.
When I arrived, it looked like a fairly
modern silver 68cm unit but when I
checked the model, it was a TC68V86A
which uses a fairly old MX4M chassis. The set wasn’t dead but was only
showing a blue raster with no TV, AV1
or AV2 video. Instead, there was only
AV sound even though every source
was working!
When I removed the back, I could
see that the set had been corroded due
to its proximity to the beach for most
of its life. This corrosion was worse
I was contracted for a service call
to an NEC FS68T90 TV in a primary
school classroom.
The complaint was that the set
wouldn’t start and I thought that the
repair would be straightforward. Unfortunately, I arrived while the class
was in full steam and I was as much a
distracted by the kids and their antics
as they were by me.
The first thing I noticed was a little box marked “Video Commander”
screwed to the top of the back shell of
the cabinet. “What the heck is that?”,
I thought.
The next thing I noticed was that
the power cord from the TV set was
plugged into this box, which in turn
was plugged into the mains wall
socket. I unplugged the TV from the
box and connected it directly to the
wall socket, switched the TV on and
it worked OK. Obviously, there was
nothing wrong with the TV; it had to
be the box.
It took a little while before I understood what was happening here. The
school had recently been upgraded
and a computerised system had been
installed which was controlled in
the library. When a teacher wanted
to show a particular video to a class,
he/she would book that video in the
library which would then route it into
that classroom via the Video Commander at the time requested.
It initially struck me that such a
system was a little bit of overkill in
terms of complexity and resources.
Why not have individual VCRs and
just borrow the tapes?
On second thoughts, it’s probably an
excellent scheme. There’s no chance
of the tapes getting lost and the number of VCRs required is dramatically
reduced, along with their maintenance
requirements.
Perhaps the “guvmint” really knows
SC
what it’s doing after all!
siliconchip.com.au
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CHIP
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which is now out of date and the advertiser
has requested that the page be removed to
prevent misunderstandings.
Please feel free to visit the advertiser’s website:
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CHIP
If you are seeing a blank page here, it is
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has requested that the page be removed to
prevent misunderstandings.
Please feel free to visit the advertiser’s website:
www.jaycar.com.au
SILICON
CHIP
If you are seeing a blank page here, it is
more than likely that it contained advertising
which is now out of date and the advertiser
has requested that the page be removed to
prevent misunderstandings.
Please feel free to visit the advertiser’s website:
www.jaycar.com.au
SILICON
CHIP
If you are seeing a blank page here, it is
more than likely that it contained advertising
which is now out of date and the advertiser
has requested that the page be removed to
prevent misunderstandings.
Please feel free to visit the advertiser’s website:
www.jaycar.com.au
SILICON
CHIP
If you are seeing a blank page here, it is
more than likely that it contained advertising
which is now out of date and the advertiser
has requested that the page be removed to
prevent misunderstandings.
Please feel free to visit the advertiser’s website:
www.jaycar.com.au
SILICON
CHIP
If you are seeing a blank page here, it is
more than likely that it contained advertising
which is now out of date and the advertiser
has requested that the page be removed to
prevent misunderstandings.
Please feel free to visit the advertiser’s website:
www.jaycar.com.au
SILICON
CHIP
If you are seeing a blank page here, it is
more than likely that it contained advertising
which is now out of date and the advertiser
has requested that the page be removed to
prevent misunderstandings.
Please feel free to visit the advertiser’s website:
www.jaycar.com.au
SILICON
CHIP
If you are seeing a blank page here, it is
more than likely that it contained advertising
which is now out of date and the advertiser
has requested that the page be removed to
prevent misunderstandings.
Please feel free to visit the advertiser’s website:
www.jaycar.com.au
PRODUCT SHOWCASE
Altronics’ “Proart”: and you shall have music wherever you go
The fact that the Proart home audio
distribution system appears in the same
issue as a major home theatre projector review is purely coincidental . . .
but timely!
For those thinking about installing a
home theatre system, the Proart Audio
Distribution System could be just what
they are looking for, the perfect accompaniment. And for those who have
never even considered a home theatre
system but liked the idea of piping
any types of audio signals anywhere
around the home – in fact, a variety of
different audio signals at the same time
to a number of different rooms with
complete control – this system is well
worth a second (or third!) look.
With many new homes these days
being Cat5 “wired” for data during the
building stage, maybe wiring for audio
– controlled by a system such as this –
should also be a high priority.
And for commercial/industrial users, the Proart could also solve a lot of
audio problems (eg, sound through a
building).
But we are getting a bit ahead of the
game. First of all, what is the Proart
Audio Distribution System?
From Altronics (who also had a
hand in the design), it’s a new and,
we believe, quiteinnovative method
of controlling and routing up to eight
input sources to up to 12 speaker zones
(rooms, if you like) or if you prefer, less
stereo and/or surround sound zones.
What’s more, it’s fully remote controllable, it connects together using
Cat5 cable and RJ45 connectors and
it’s delightfully easy to install and
configure.
Stacked for our photo, the
A5024 12-channel amplifier (top) and
the A5020 Matrix Control Unit below. Inset
is one of the infrared remote control unit wall plates
along with its controller.
There are three components to the
system (not including the eight audio program sources, which you can
choose yourself to suit your requirements, anything from tuners to DVD,
CD or even TV sound. You could even
have different tuners feeding different
radio stations).
First is the A5024 multi-channel
amplifier. Well, that’s probably a misnomer: this beast actually contains
twelve independent 40W amplifier
modules, which may be connected
any way you wish (ie, 12 single (mono)
rooms, 6 rooms with stereo, 1 room
with 6-channel surround sound and
6 other rooms, etc etc).
The amplifiers can also be oper-
ated in bridge mode to achieve higher
power – in fact, you could operate
all in bridge mode to achieve three
stereo amplifiers of 120W per channel capacity.
As well as standard RCA socket
input for each channel, there are
RJ45 “bus” inputs for each channel
with switches to select between the
Continued on p70
STEPDOWN
TRANSFORMERS
60VA to 3KVA encased toroids
Harbuch Electronics Pty Ltd
The back panel of the A5024 12-channel amplifier, shows what a busy beast it
is! The sockets immediately below the RCA input sockets are for the buses.
siliconchip.com.au
9/40 Leighton Pl. HORNSBY 2077
Ph (02) 9476-5854 Fx (02) 9476-3231
August 2006 69
Proart Audio Distribution System – continued
two. What are the bus inputs for?
Read on!
Performance-wise, it’s no slouch:
each amplifier has THD of <.005%
(20Hz-20kHz), frequency response is
within 0.4dB 10Hz-50kHz and it has
better than 60dB crosstalk and 80dB
hum and noise.
It can be powered from 240V AC
or 24V DC.
That’s the amplifier – pretty impressive in its own right. But it’s when
you team it up with the A5020 Matrix
Control Unit that the goalposts move
– right into the next field!
Matrix controllers can basically
connect any input to any output – in
whatever combination you wish. The
Proart A5020 will do this but it will do
so much more. It’s used in conjunction
with the A5026 wall plate to give total
infrared remote control – not just of the
signal program switching and volume,
but will also allow other devices such
as CD/DVD players, etc, in other rooms
to be remotely controlled.
Each channel has RCA inputs and
outputs but, like the 12-channel amplifier, the controller also has RJ45
“buss” outputs which to link it to the
same connectors on the amplifier or
the wall plates.
As well as being “receivers” for the
remote control, the A5026 wallplate
has pushbuttons for manual control.
A LED display and indicators show
the current volume setting and sig-
PC-Bay LCD Information
nal sources. The unit fits a standard
electrical wall box and is wired with
standard Cat5/RJ45 cable. In most cases, a single wallplate will adequately
cover even a large room but if more
wallplates are needed, they can be
“daisy chained” (just like computer
networks).
There’s also a range of infrared accessories to suit the system – it’s best
to refer to the Proart brochure (downloadable from http://www.altronics.
com.au/download/Brochures/Audio/
A5020.pdf)
OK, you can probably tell that we
are impressed by the Proart Audio
Distribution System. It’s not cheap
– but it is significantly cheaper than
anything else on the market (and
we’re not convinced they will do the
job as well).
The A5020 Matrix Control Unit
sells for $990, the A5024 12-channel
amplifier $1099 and the A5026 remote
control panels $199 each for two or
more (and you’ll need more than two!).
There’s also a package deal but there’s
not a great deal of point talking about
it because it costs exactly the same as
the individual units!
Dominion Electronics has available two
new series of MX series LCD Digital Information Inserts.
Made by Matrix Orbital, these are designed to fit into standard PC front-panel
cutouts – single height in the case of a the
MX200 series and double height for the
MX400 series.
They can be used to give information
about the operation of the PC or can be used
in place of a monitor. The MX200 offers a
20 x 2-line display, while the MX400 has a
20 x 4-line. Display colours are green on
yellow, blue on cool white, white on blue
or inverse yellow. The display draws 25mA;
the backlight 150mA.
They’re available with or without a
7-key keypad and a USB or serial (TTL)
interface.
The MX200 sells for $155.00 (+GST)
while the MX400 is $212.00 (+GST).
Contact:
Contact:
174 Rowe St, Perth WA 6000
Tel: (08) 9428 2199 Fax: (08) 9428 2198
Website: www.altronics.com.au
U13, 82 Reserve Rd, Artarmon NSW 2064
Tel: (02) 9906 6988 Fax: (02) 9906 7145
Website: www.dominion.net.au
Altronics Distributors
Dominion Electronics Pty Ltd
Smartcal and TRIO Test & Measurement Solutions merge
SmartCal and TRIO Test & Measurement Solutions announce their merger
on 1st July 2006.
The new company, TRIO Smartcal
Pty Ltd offers a one-stop-shop for test
equipment sales, service and calibration.
Smartcal, Australia’s most experienced Tektronix service, repair and
calibration providerwas formed by
ex-employees of the Tektronix service
department when Tektronix closed their
Australian T&M office in 2001.
Smartcal is also the authorized Calibration Provider for National Instruments
and in addition offers repairs and calibration on many other leading brands such
as Fluke and takes pride in its integrity
and loyalty to its customers.
TRIO was formed 40 years ago in
70 Silicon Chip
Adelaide and has grown to be one of Australia’s premier national T&M distributors
representing world-class suppliers such
as Fluke, Yokogawa, LeCroy, Hameg and
Rohde & Schwarz. TRIO T&M also has a
manufacturing division and is Australia’s
premier manufacturer of portable appliance testers.
The new company offers a complete
test and measurement solution, including
pre- and post-sales advice, technical support, repair and calibration. TRIO Smartcal
provides national geographic coverage
with offices in Sydney, Brisbane, Adelaide
and Melbourne.
An interesting service is the custom
R&D bench which can be rented on a daily
basis when customers have a project but
do not need to buy, or cannot afford to
buy, a lot of performance test equipment
such as spectrum analyzers, signal and
arbitrary waveform generators, performance oscilloscopes etc.
TRIO Smartcal can offer un-biased
advice for users of older test equipment
whether repair or replacement is the
most economical course of action. This
differs from organizations focused only
on repair or sales where customers do
not get this un-biased choice or advice.
In most cases if replacement is chosen
TRIO Smartcal will offer a trade-in allowance for the old test equipment.
Contact:
Trio Smartcal Pty Ltd
3 Byfield St. North Ryde NSW 2113
Tel: 1300 853 407 Fax: 1300 853 409
Website: www.triotest.com.au
siliconchip.com.au
And the
winner is...
A NOTE TO
SILICON
CHIP
SUBSCRIBERS
Your magazine address sheet shows when
your current subscription expires.
This month’s winner of one of
these superb DSE 20MHz dualchannel ’scopes in the SILICON CHIP
subscriptions promotion is:
Glenn Collins of
Wavell Heights, Qld.
Check it out to see how many you still have.
If your magazine has not turned up by the
first week of the month, contact us at
silchip<at>siliconchip.com.au
Three new Eddystone boxes from Hammond Electronics
Hammond Electronics,
one of the world’s leading
manufacturers of small diecast aluminium and plastic
enclosures, purchased the
tooling and intellectual property of the well-know Eddystone range from Marconi in
1998. The complete range of
European and North American manufactured Hammond
enclosures is now available
from national, regional and
local distributors throughout
Australasia.
Probably one of the best
know brands in the small enclosure sector, the
Eddystone range consists of nine sizes of thin
siliconchip.com.au
wall shallow lid general purpose
die-cast aluminium enclosures
and a further five variants fitted
with a deep lid.
Hammond’s Australian
operation is a manufacturer in its own right. Hammond Electronics Pty has
introduced a further three
sizes to complement the
original 14-strong family.
Designed and manufactured only in Australia, the
new sizes are 50 x 50 x
21, 92 x 92 x 38 and 125 x
125 x 53mm. In addition to
serving the needs of the local market, the
Australian manufactured enclosures are
exported in large volumes to Hammond’s
European operation.
SC
Contact:
Hammond Electronics Pty Ltd
GPO Box 812, Adelaide SA 5001
Tel: (08) 8235 0744 Fax: (08) 8356 3652
Website: www.hammondmfg.com
August 2006 71
Ever wanted to be able to listen to the
‘unlistenable’ – sounds that are
way beyond the range of normal
human hearing? Like the supersonic whine of a gas leak, or the
echo-location ‘chirps’ of bats?
Here’s a low-cost project that
will let you do just that. It’s a
down-converter which shifts
ultrasonic sound signals down
into the frequency range where
they can be heard (or recorded).
by
Jim Rowe
ULTRASONIC
EAVESDROP
A
FEW WEEKS AGO, I found myself watching a wildlife doco on TV in which naturalists were studying
the behaviour of bats. They were using infrared
lighting to photograph them and a down-converter so that
they could hear and record the ultrasonic ‘chirps’ that the
bats use for navigation in the dark – and often for tracking
down their insect prey.
My curiosity was aroused and I decided to ‘have a go’
at coming up with a low cost down-converter of my own.
This project is the end result, presented so that other readers can indulge their curiosity as well.
I won’t claim that the project has all kinds of uses,
because it’s mainly going to be useful for listening to the
ultrasonic sounds emitted by bats and one or two other
nocturnal insect-eating creatures.
But you should also be able to use it to track down the
exact location of high-pressure gas leaks -- which apparently also produce an ultrasonic whistle or whine. You
could even use it to make sure an ultrasonic dog whistle
is working, if Fido seems to be ignoring it (perhaps his
hearing has deteriorated like mine)!
How it works
Most of the sounds emitted by bats are in the frequency
range from about 15kHz to 50kHz, with a few extending
72 Silicon Chip
up to about 150kHz and a small number extending down
below 10kHz.
So most of them are above the range of human hearing,
and some well above. (Young people can often hear up to
about 18-20kHz but this upper limit generally falls as we
grow older.)
The idea of the eavesdropper is to shift the ultrasonic
sounds down in frequency, so they fall within our comfortable hearing range.
This is done by using the heterodyne principle, in much
the same way as it’s used in many radio receivers. Or more
accurately, in exactly the same way as it’s used in ‘direct
conversion’ receivers: we mix the incoming ultrasonic
signals with a continuous ultrasonic signal from a ‘local
oscillator’.
In the mixer the two signals heterodyne or ‘beat’ together,
generating signals which correspond to the sum and difference of the two frequencies.
The ‘sum’ signal will be very high in the ultrasonic
range – and thus even more inaudible – but the ‘difference’
signal is easily arranged to be much lower in frequency and
therefore in the audible (to humans!) range.
You can see how this down-conversion system works
from the block diagram in Fig.1.
The ultrasonic sounds are picked up by a small electret
siliconchip.com.au
PPER
microphone, which turns them into small ultrasonic electrical signals. This type of microphone has a frequency
response which extends well up into the ultrasonic region.
The signals are then passed through a preamplifier to
boost them to a more useful amplitude (or level), where
they can be passed into one input of a balanced mixer.
The other input to the mixer is fed with a continuous
ultrasonic signal produced by a tuneable ‘local oscillator’,
so it can be varied in frequency from about 15kHz to 50kHz.
As a result the output of the balanced mixer contains
three main frequency components: the difference signals
(FIN - FOSC) and (FOSC - FIN), and the sum signal (Fin +
FOSC). The sum signal is obviously even higher in the
ultrasonic range than FIN and FOSC, so it’s of no interest
to us. We filter it out, anyway. But by adjusting the tuning
of the local oscillator the difference signals can be placed
down in the audible range, so all we have to do is feed
them through an audio amplifier (via a volume control),
before they can be either heard in a
pair of headphones or sent to a tape
or other recorder (even recorded on a
computer hard disk or memory card for
later analysis).
What’s with the dish?
Fig.1: the block diagram shows the various functional elements
of the Ultrasonic Eavesdropper.
siliconchip.com.au
Used by itself, the electret microphone insert works – but not very well.
To make it more effective, we concentrate the ultrasonic sound waves with
a small, “somewhat” parabolic dish.
As you may recall from previous
SILICON CHIP projects, a parabolic dish
reflects all the waves which strike it
back to its focal point. With the miAugust 2006 73
74 Silicon Chip
siliconchip.com.au
1nF
220k
10nF
4.7k
4
6
9
8
VR2
5k
8
470Ω
220k
1
5
6
IC3: LM833
8
O5-9
12
O0
O1
O2
O3
O5
O6
O7
O8
O9
1
5
6
9
11
3
2
4
7
IC2
4017B O4 10
CP1
Vss
MR
CP0
IC3a
470nF
2
3
PREAMP
GAIN
180k
13
15
10 14
6.8k
7
14
Vdd
ULTRASONIC EAVESDROPPER
MIC
INPUT
CON1
47 µF
5
VR1 5k
IC1b
11
OSCILLATOR
FREQUENCY
1.2k
MIC1
ELECTRET
INSERT
2
IC1a
13
IC1d
IC1c
16
4
IC3b
16k
10k
16k
120k
120k
7
22 µF
100nF
100nF
680Ω
100nF
1k
+12V
4.7nF
11k
11k
30k
30k
100nF
1k
560Ω
470Ω
8
10
1.5k
+12V
3
1k
14
MIXER
BALANCE
VR4
1
6
4.7nF
12
470Ω
4
5
10k
λ LED1
1k
IC4
MC1496
2
220Ω
K
A
Fig.2: the circuit beats the “bat” frequency against the supersonic generator formed by IC1 and IC2.
SC
2006
+
100nF
1
3
12
IC1: 4093B
100nF
4.7nF
4.7nF
1k
2x
3.3k
100 µF
100Ω
A
ZD1
K
2
VOLUME
VR3
10k 3
2.2 µF
6
1
4
10 µF
IC5
LM386N
ZD1
12V
1W
220 µF
A
K
100Ω
7
8
5
10Ω
47nF
220 µF
2200 µF
K
A
D1 1N4004
A
K
1N4004
LED
12-15V
DC
INPUT
STEREO
PHONES
CON2
RECORD
OUT
CON4
1k
A
K
CON3
Fig.3: the entire
project mounts on a
single PC board, with
the electret mic insert
connected via an RCA
socket on the left side.
The sockets on the
right connect power
(12VDC), earphones
and some form of
audio recorder. We
used IC sockets (as
seen in the photo
below) but these are
not really necessary.
crophone insert mounted at the focal point (or as close
as we can guess!), pick-up becomes much more efficient
and effective.
This dish can be made from just about any material which
will reflect sound waves – we used a laminated wood cereal
or salad bowl, bought from a ‘bargain store’ for just a couple
of dollars. It is about 155mm in diameter and about 39mm
deep but this is not at all critical – a larger dish should be
even better but would start to become unwieldy.
A similar (hard) plastic or even stainless steel salad bowl
could also be used.
We said a moment ago that it was “somewhat” parabolic
in shape – it has a flat bottom. This might not be technically
ideal but it is good enough for our purposes – and certainly
makes it a lot simpler to attach things to!
You can work out the focal point of a parabola by formula
(but it is complicated by the flat bottom), or you could line
the bowl with aluminium foil and aim the bowl at the sun
to enable you to get it spot on (as we did for the dishes
used in our WiFry articles).
Another way of finding the focal point would be to connect the mic insert to an audio amplifier and aim the dish
at a single point sound source (such as a speaker connected
siliconchip.com.au
to an oscillator). Moving the microphone back and forward
along the centre axis would reveal one point where the
maximum signal was found.
Having said all that, we found near enough (an educated
guess) was good enough – but feel free to experiment with
distances!
We’ll look at mounting the dish and microphone a little later.
The circuit
Now let’s look at the circuit diagram (Fig.2) for a more
detailed understanding of how it works. The ultrasonic
sounds are picked up by the electret microphone insert,
MIC1.
The fairly small signals from MIC1 are fed in via CON1
and first amplified by IC3a, half of an LM833 dual low-noise
op amp. It’s used here as a preamp with its gain variable
between about 40 and 400, using trimpot VR2.
This allows the project to be set up for either short or
long range bat monitoring, and with bats having either loud
or soft ‘chirping’ (they do vary, between species).
After amplification, the signals are passed through IC3b,
the ‘other half’ of the LM833, connected as a unity-gain
August 2006 75
The completed PC board screwed to
the lid of the UB-3 box, which becomes
the base. Actually, this photo is a tad premature
in the assembly sequence because you need to screw the
lid to the timberwork, then fit the PC board to the lid.
buffer to provide a low impedance source feeding the mixer
IC4, via a 1kW series resistor.
The ultrasonic signal used for our ‘local oscillator’ is
generated using IC1 and IC2. This signal (a) needs to be
tuneable over a fairly wide frequency range; (b) should be
reasonably low in harmonic content and (c) should also be
fairly constant in amplitude. However, this combination of
qualities is not easy to produce using conventional audio
oscillator circuits.
So we generate it in a slightly unusual fashion. Gates
IC1a, IC1b & IC1d are used as a relaxation-type oscillator,
producing a square wave clock signal which is variable
between 150kHz and 500kHz using pot VR1. This clock
signal is buffered by gate IC1c and fed into the clock input
of IC2, a 4017B Johnson-type decade counter.
This IC therefore counts the clock signals so that its 10
outputs, O0 - O9, switch high in turn, on a continuous
cyclic basis. These outputs are used to drive a simple
digital to analog converter (DAC) using a set of resistors.
While it may appear that output O7 is not used, it is – its
“infinite value” resistor (ie, open circuit!) actually sets
the zero point.
The values of the resistors are carefully chosen so that
as the outputs of IC2 go high in turn, a 10-sample approximation of a sinewave is developed across the output
(ie, the 680W resistor between pins 10 and 8 of IC4). The
4.7nF capacitor which is also across the output provides
a measure of low-pass filtering and further ‘smoothing’ of
Here you can see how the plastic case needs to
be drilled and slotted . . .
76 Silicon Chip
the sinewave.
The result of this simple
digital waveform synthesis is a fairly
smooth sinewave signal of reasonably constant amplitude,
with a frequency exactly one tenth that of the clock signal
from IC1. So as the clock signal is varied between 150 and
500kHz via VR1, the ‘local oscillator’ sinewave signal at the
pin 10 input of IC4 is varied between 15kHz and 50kHz.
IC4 is an MC1496 double-balanced mixer, expressly
designed for this kind of use. When we feed our amplified
ultrasonic sound signal into its pin 1 input and our local
oscillator signal into its pin 10 input, it performs analog
multiplication between them and provides the corresponding sum and difference frequency signals at its outputs (pins
6 and 12, which are simply dual polarity outputs).
By the way, the mixer strictly only produces just the sum
and difference signals at its outputs when it is carefully
balanced using trimpot VR4. If it is not truly balanced, both
of the input signals can also be present in the outputs –
although this is not a major problem here because both of
these input signals are inaudible.
All the same, it’s a good idea to have the mixer reasonably close to balance, to reduce distortion in the audio
amplifier.
We’ll explain how to
do this later.
. . . so that the PC
board is an easy fit.
Again, the lid is screwed
to the handle before the board is
placed inside the box.
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As you can see in this project we take the mixer
output signal from pin 6 of IC4 and then pass
it through a simple low pass filter using the
1kW series resistor and 4.7nF capacitor (across
volume control VR3). This filtering attenuates
the ‘sum’ frequency components quite
significantly, leaving mainly just the
audible ‘difference’ components that
represent the downshifted version of
our ultrasonic sound signals. We then
pass these through audio amplifier IC5,
after adjusting their volume level via pot VR3.
The amplified output of IC5 is used to drive a
standard pair of stereo headphones via CON4 and/
or an audio recorder via line-level output CON2.
The complete circuit is designed to operate from
almost any source of 12-15V DC, which is fed in via
CON3 and can come from either a small AC plugpack
supply or a nominal 12V battery such as that in a car or
motorcycle.
The total current drain is less than 35mA, so you could
also run it from a pair of 6V lantern batteries connected
in series or even a pack of eight ‘C’ cells. Zener diode ZD1
limits the voltage which can be fed to ICs1-3, while LED1
is an indicator that power is applied.
Construction
All of the Eavesdropper circuitry is mounted on a
single PC board, measuring only 122 x 57mm and coded
01208061. As you can see the board has rounded cutouts at
each corner so it can be mounted snugly inside a standard
plastic utility box measuring 130 x 68 x 44mm.
Microphone input socket CON1 is mounted on the lefthand end of the board, while the DC input, headphone
output and recording output connectors are all mounted
on the right-hand end.
The local oscillator ‘tuning’ pot VR1, power LED1 and
volume control pot VR3 are all mounted along the front
side for easy accessibility.
Begin construction by checking the PC board for any
etching problems or undrilled holes and fixing these before
you proceed. Then it’s a good idea to fit the various connectors (CON1-CON4), as these sometimes require a small
The “gun” assembly
immediately before the UB-3 case
lid is secured. You can clearly see
the way that the piece of coat hanger
wire which supports the electret
microphone is attached.
amount of fiddling and board hole enlargement.
There is only one wire link to be fitted to the board, so I
suggest you fit this next to make sure it isn’t forgotten. It’s
located just behind CON4, at lower right as viewed in the
PC board overlay diagram.
Next fit the various fixed resistors, taking care to fit
each one in its correct position. These can be followed by
trimpots VR2 and VR4, making sure you don’t swap them
around. The 5kW trimpot is VR2, while the 1kW trimpot
is VR4. Don’t fit the two larger pots at this stage, though –
they’re best fitted later.
Now you can fit the capacitors, starting with the two
100nF multilayer monolithics (near IC1 and IC2) and
then progressing through the small MKT caps, the 2.2mF
tag tantalum electrolytic (just to the front of IC5) and then
the other electrolytics. Remember that all the electrolytics
are polarised, so make sure you orient them correctly (as
shown in Fig.3, the PC board overlay diagram).
After these you can fit the semiconductors, starting with
diode D1 and zener diode ZD1 – again make sure you don’t
swap these accidentally and that they are both fitted with
the correct orientation as shown in the overlay diagram and
Fig.4: use this diagram in conjunction with the
photo above to work out which bit goes where!
siliconchip.com.au
August 2006 77
photos. Then fit the ICs, preferably in reverse numbered
order (ie, IC5 first, then IC4, working your way back to IC2
and IC1). Even though we did, there is no need to fit any
of the ICs in sockets unless you wish to. All five ICs must
be oriented as shown.
If you are soldering IC2 and IC1 directly into the board,
take care to protect them from the possibility of electrostatic
damage. Use an earthed soldering iron, earth yourself if
possible (or at least discharge yourself before handling the
ICs) and solder the supply pins of the ICs first (pins 7 and
14 on IC1, pins 8 and 16 on IC2) to enable their internal
protection circuitry as early as possible.
After the ICs are all in position, it’s time to fit power LED1.
This is fitted to the board vertically to begin with, with its
longer anode lead to the right and both leads soldered to
their pads underneath with the LED’s body about 18mm
above the board. Then using a pair of needle-nose pliers
or similar, bend both leads forward by 90°, 12mm above
the board. This will position the LED facing forward and
ready to protrude through the matching hole in the box,
after final assembly.
The last two components to mount on the board are
control pots VR1 and VR3, which are both fitted along the
front of the board on either side of LED1. You may need to
cut the pot spindles to about 10-12mm long before they’re
fitted, if they’re not already this length. Make sure you fit
Fig.5: hole drilling diagram for a UB-3 plastic box.
78 Silicon Chip
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the 5kW linear (B) pot as VR1, and the 10kW log (A) pot as
VR3, as shown in the overlay diagram.
Your Eavesdropper board should now be complete and
ready to be fitted to the lid of the UB3 box, which is used
here as the base. But before doing this, you may need to
prepare both the lid and the box itself, by drilling and
cutting the various holes that are needed for mounting, assembly and access to the various connectors and controls.
The location and dimensions of all of these holes are shown
in the drilling diagram (Fig.5), so you shouldn’t have any
problems if you use this as a guide.
The hardware
It would also be a good idea at this stage to make the
Eavesdropper’s wooden ‘handle’ and attach to its front the
small dish we mentioned earlier.
The dish is simply attached to the front of the wooden
handle using a couple of 15mm long self-tapping screws,
passing through 3mm holes drilled in the centre of the
bowl. Two further 3mm holes were drilled just above these
mounting holes to allow the mic support ‘bracket’ and its
shielded lead to pass through.
The mic support bracket was bent up from a 200mm length
of 2.2mm diameter steel wire, salvaged from a coat hanger.
After straightening and cutting to length, the wire was bent
into a small loop at one end (around the shank of a 4mm
twist drill). Then the straight section of wire was passed
through the matching hole in the back of the bowl, and the
loop end attached to the top of the wooden handle about
45mm behind the bowl using a 15mm long woodscrew,
with a small flat washer under the screw head.
The front end of the bracket was then bent around and
downwards in an open ‘J’ shape, about 20mm in diameter,
so the end was aligned very closely with the centre axis
of the bowl and about 65mm in front of the bowl’s inside
centre – corresponding to an approximation of this bowl’s
likely ‘focus’ as an ultrasonic reflector.
Then the mini electret mic insert was cemented to the
side of the wire’s end using epoxy cement, with its ‘front’
facing the centre of the bowl (ie, it looks backwards, not
forwards).
After the epoxy cement has cured, solder the wires at
one end of a 300mm length of light duty, screened microphone cable to the mic insert connection pads, with the
cable screen wires connected to the insert’s earthy/case pad
and the inner wire to the other ‘+’ pad. This is a slightly
tricky job, as the pads are very small and closely spaced.
So take your time, and take care not to overheat the mic
insert in particular.
If you’re new to soldering, it might surprise you to find
that a hot, well-tinned iron poses much less danger than
a cooler iron. The solder job is completed much more
quickly – before the insert has had a chance to realise it’s
getting hot!
It’s also a good idea to connect the cable screen to the
wire support bracket just near the mic using a short length
of fine tinned copper wire, to minimise hum pickup.
The free end of the mic cable is then passed back through
the remaining hole in the centre of the bowl and fitted with
a metal-shelled RCA plug at the other end ready to plug
into the Eavesdropper.
To prevent the cable from flapping around it can be
fastened to the mic supporting wire using three short
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Parts List – Ultrasonic Eavesdropper
1
1
2
1
1
1
1
1
4
4
8
2
PC board, code 01208061, 122 x 57mm
Plastic utility box, UB3 size (130 x 68 x 44mm)
RCA socket, PC-mount (CON1, CON2)
2.5mm DC socket, PC-mount (CON3)
3.5mm stereo socket, PC-mount (CON4)
Electret mic insert, miniature type
300mm length of screened mic cable
RCA plug, metal screened type
10mm long M3 machine screws, countersink head
M3 star lockwashers
M3 nuts
Small control knobs (for VR1 and VR3)
Semiconductors
1 4093B quad Schmitt NAND gate (IC1)
1 4017B decade counter (IC2)
1 LM833 dual low noise op amp (IC3)
1 MC1496 double balanced mixer (IC4)
1 LM386N audio amplifier (IC5)
1 12V 1W zener diode (ZD1)
1 3mm green LED (LED1)
1 1N4004 1A diode (D1)
Capacitors
1 2200mF 16V RB electrolytic
2 220mF 16V RB electrolytic
1 100mF 16V RB electrolytic
1 47mF 16V RB electrolytic
1 22mF 16V RB electrolytic
1 10mF 16V RB electrolytic
1 2.2mF 35V TAG tantalum
1 470nF MKT metallised polyester
5 100nF MKT metallised polyester
2 100nF multilayer monolithic
1 47nF MKT metallised polyester
1 10nF MKT metallised polyester
4 4.7nF MKT metallised polyester
1 1nF MKT metallised polyester
Resistors (0.25W 1%)
2 220kW
1 180kW
2 120kW
2 30kW
2 16kW
2 11kW
2 10kW
1 6.8kW
1 4.7kW
2 3.3kW
1 1.5kW
1 1.2kW
5 1kW
1 680W
1 560W
3 470W
1 220W
2 100W
1 10W
1 5kW linear pot, 16mm or 24mm PC-mount (VR1)
1 5kW mini trimpot, horizontal PC-mount (VR2)
1 10kW log pot, 16mm or 24mm PC-mount (VR3)
1 1kW mini trimpot, horizontal PC-mount (VR4)
lengths of ‘gaffer’ tape (visible in the photos) wrapped
around them both.
At this stage, we gave the whole assembly a couple of
coats of matte black spray paint. It looks 100% better than
leaving it “au naturel”, which looks like a wooden salad
bowl screwed to a piece of timber . . .
If you do this, don’t forget to completely cover the electret mic insert in adhesive tape to stop it getting painted.
Masking tape is preferable because ordinary adhesive tape
can be a real pest to remove!
Once the handle-dish-mic assembly is complete, you
August 2006 79
01208061
Fig.6 (above): the same-size PC board pattern, while below, (Fig 7) is the same-size
front panel artwork. We simply laminated and glued the paper label to the box,
leaving about a 2mm border around the edge.
can attach the Eavesdropper’s lid/base
plate to the top rear of the wooden
handle using a couple of 15mm long
woodscrews through the two 3mm
holes in the centre. As you can see the
lid is orientated at right angles to the
handle axis, and centred over it.
With the box lid attached to the
handle, you can fit the Eavesdropper’s finished PC board assembly to
the lid.
It’s attached using four 10mm long
M3 machine screws with countersink
heads, passed up from below and each
then fitted with a star lockwasher and
M3 nut. These nuts act as spacers, so
the screws and nuts should be firmly
tightened before the board assembly
is fitted. Then when it is in position,
four further nuts are used to hold it
in place.
Checkout and adjustment
When the PC board assembly is fixed
in place, it’s time to fire up the Eavesdropper and give it a quick functional
checkout.
Set both of the main control pots to
roughly their midrange positions and
also set both trimpots to their midrange
positions using a small screwdriver or
alignment tool. Then plug the mic cable into CON1, a pair of standard stereo
headphones into CON4 (but don’t put
them on yet, just in case something is
Resistor Colour Codes
o
o
o
o
o
o
o
o
o
o
o
o
o
o
o
o
o
o
o
o
No.
2
1
2
2
2
2
2
1
1
1
1
1
5
1
1
3
1
2
1
80 Silicon Chip
Value
220kW
180kW
120kW
30kW
16kW
11kW
10kW
6.8kW
4.7kW
3.3kW
1.5kW
1.2kW
1kW
680W
560W
470W
220W
100W
10W
4-Band Code (1%)
red red yellow brown
brown grey yellow brown
brown red yellow brown
orange black orange brown
brown blue orange brown
brown brown orange brown
brown black orange brown
blue grey red brown
yellow purple red brown
orange orange red brown
brown green red brown
brown red red brown
brown black red brown
blue grey brown brown
green blue brown brown
yellow purple brown brown
red red brown brown
brown black brown brown
brown black black gold
5-Band Code (1%)
red red black orange brown
brown grey black orange brown
brown red black orange brown
orange black black red brown
brown blue black red brown
brown brown black red brown
brown black black red brown
blue grey black brown brown
yellow purple black brown brown
orange orange black brown brown
brown green black brown brown
brown red black brown brown
brown black black brown brown
blue grey black black brown
green blue black black brown
yellow purple black black brown
red red black black brown
brown black black black brown
brown black black gold brown
siliconchip.com.au
Two views looking for’ard and aft. If you paint the whole
shebang black, like we did, make sure you wrap a piece
of masking tape around the microphone insert first. They
don’t like being covered in paint!
wrong!) and the cable from your 12V
battery or plug pack into CON3.
Power LED1 should immediately
light up, to show that the circuit is
operating. If the LED doesn’t light, this
will probably be because one of three
components is fitted to the board with
reversed polarity: LED1 itself, D1 or
ZD1. Either that or the plug on your
DC input cable is wired with reversed
polarity.
With your multimeter you can check
the voltage between the anode of D1
and the board’s ground – it should be
the same as the incoming DC. Similarly
the voltage at the cathode of D1 should
Capacitor Codes
Value
470nF
100nF
47nF
10nF
4.7nF
1nF
μF Code
0.47µF
0.1µF
.047µF
.01µF
.0047µF
.001µF
siliconchip.com.au
EIA Code
474
104
473
103
472
102
IEC Code
470n
100n
47n
10n
4n7
1n0
be only 0.6V lower, while that at the
cathode end of ZD1 should be a little
lower again. You should also be able
to measure the same voltage at pin 14
of IC1, pin 16 of IC2 and pin 8 of IC3.
Similarly at pin 6 of IC5 you should
find the same voltage as you measured
at the cathode of D1.
Listen to the headphones without
actually putting them on. If they are
not shrieking, place the headphones
on your ears and you should hear a
small amount of noise and/or hum. If
you turn up volume control pot VR3,
this noise should increase a little,
showing that the audio section of the
circuit is working correctly.
Now try returning VR3 to its midrange position and adjusting ‘tuning’
pot VR1 up or down. You may hear
a faint heterodyne ‘whistle’ as you
tune through one position in the tuning range. This is probably due to
the mic preamp picking up a small
amount of RF from a local AM radio
station, which then heterodynes with
the Eavesdropper’s local oscillator or
one of its harmonics. This is not likely
to interfere with the Eavesdropper’s
normal operation but if nothing else
it shows that the Eavesdropper’s local oscillator, ultrasonic preamp and
mixer sections are all working.
If all seems well at this stage, your
Eavesdropper is probably working
correctly and all that remains to be
done before final box assembly is to
set the mixer balance trimpot VR4 to
the correct position.
Got a ’scope?
Mixer balance adjustment is easiest
with an oscilloscope but if you don’t
have access to one, you don’t really
have to concern yourself about it;
simply leave VR4 set to its midrange
position, which is very likely to be
‘near enough’ for most purposes.
If you do have access to a scope and
you want to set the mixer for the best
possible performance, the adjustment
is quite easy.
All you need to do is monitor the
level of the Eavesdropper’s ‘local
oscillator’ signal appearing at pin 6
of IC4 with your ’scope, while adjustAugust 2006 81
Here’s what the finished project looks like, ready
to use (all you need is a 12V battery pack!). The
headphones can be just about anything – including
the bargain shop $2 cheapies!
ing VR4 with a small screwdriver. At
either end of the trimpot’s range the
signal will increase in level, while
it will pass through a minimum or
‘null’ somewhere near the middle of
the range.
The correct setting for VR4 is right
at the centre of this null – this corresponds to the mixer being balanced.
Final assembly
The final assembly step is to fit the
box itself down over the PC board assembly, as a protective cover.
This is done by inverting the box
and tilting it an angle of about 45° so
that it can be offered up to the PC board
with the control pot spindles and LED1
entering their matching holes on the
box ‘front side’ from the inside.
Then the box is moved towards
the mic and reflector bowl, gradually
tilting it down so the undrilled long
side swings down outside the 220mF
electrolytic and the other components
along the rear of the board.
The slots at each end of the box will
allow the ends to clear the protruding
sleeves of RCA connectors CON1 and
CON2.
When the box has been juggled into
position, it can be attached to the lid/
base using the four small self-tapping
screws supplied with it. Then the control pots can be fitted with their nuts,
which can also be lightly tightened
to help support the pots when the
Eavesdropper is being used.
After this you can fit the knobs, and
your Eavesdropper should be ready
for use.
Using it!
The top trace of this ’scope shot shows the synthesised sine wave coming from
the ladder network of IC2. The lower (blue) trace shows the output at pin 6
of IC4. The very low mean voltage measurement of 5.38mV shows that the
modulator is balanced.
82 Silicon Chip
This is also very straightforward.
You use ‘tuning’ pot VR1 to search
for ultrasonic sounds over the Eavesdropper’s range and then when you
find one the same control is used to
shift the sounds down to a convenient
frequency for listening or recording.
Volume pot VR3 is used simply to
adjust the output audio to a convenient level.
You’ll probably find the Eavesdropper sensitive enough to pick up bat
chirps, etc with the preamp gain trimpot VR2 left in its suggested midrange
position.
However if you want to have the
highest possible sensitivity, VR2 can
be turned up to its fully clockwise
position.
Happy bat tracking!
SC
siliconchip.com.au
Making sense of all the information
Part 2: by Julian Edgar
Race Car Data Logging
This data screen shows the car, a Formula Ford, half way
through Turn 4 at the Philip Island circuit on Lap 5. (The
map in the bottom right-hand corner shows this location.)
From top to bottom, five parameters have been chosen for
graphing. These are: engine speed (4814 RPM at this point);
corrected speed (78.8km/h); throttle position (85.3 per cent);
longitudinal acceleration (0.23g); and steering angle (1.7
degrees). In addition to the graphed information, the other
logged parameters are also available in table form. They
include engine oil pressure (32.63 psi); lateral acceleration
-1.31g; suspension heights (front-left: -4.9mm, front-right:
11.3mm, rear-left: 11.9mm, rear-right: -1.1mm) and so on.
Any of these parameters can be selected for graphing.
By moving the vertical blue cursor to the left or right,
the status of the car at any position on the track can be
displayed.
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Staying on Turn 4, the race engineer can zoom in on the
graphed data so that instead of looking at one complete lap,
he or she is looking at only 10 seconds or so. The engineer
can then overlay the logged data from another lap – here
this other data is from Lap 1 and shown in black.
This indicates that the driver on Lap 1 drove quite differently; exiting Turn 4 he was 12km/h quicker and the
mid-corner steering input was dramatically changed.
Note the throttle use – a racing car spends most of its
time at either zero or 100 per cent throttle.
The data in the right-hand column can be configured
to show the absolute numbers or the relative difference
between them; the latter has been done here.
August
ugust 2006 83
2006 83
A
L
ast month we looked at the data that is now routinely
logged from sensors in racing cars. But when the car
has come into the pits, what does the race engineer
do with the logged information?
It’s interpretation, rather than collection of information
which is of the utmost importance in improving lap times.
And this is where data analysis software like MoTeC’s i2
is used.
When a drag run, such as that shown opposite, can be
over in under five seconds, having the ability to carefully
and slowly play back data log records is a huge advantage.
The first stage in analysing the data is to put it into a
frame of reference. It’s no good simply knowing that for
Video footage can be synchronised with the data as it is
played back real time, allowing observation of the driver
or even such aspects as suspension deflection or anti-roll
bar behaviour.
Data can be
logged to either a
digital dash or the existing
programmable engine
management unit.
example the peak engine speed was 6354 RPM and at one
stage the car was travelling at 217.9km/h.
That frame of reference is provided by the track map.
Using the data collected by the lateral accelerometer and
speed sensor or longitudinal accelerometer, the software
is able to construct a virtual track map. The different sections of the track can then be automatically or manually
Any of the logged parameters can be displayed in a
‘gauge’ format. The gauges are user-definable and can comprise circular bargraphs, traditional gauges with pointers,
bar graphs, or on/off status blocks. In addition, a graphic
showing the steering wheel position can be added and the
track map can be used to show the location of the car when
the data was collected.
As with the graphing described above, when the position
of the car on the track is altered, the gauges also change
to show what is occurring. An animation function is also
available where the car automatically ‘drives’ around the
track, the gauges reflecting the changing status as it does so.
This animation can occur at actual car speed or anywhere
from 0.1 to 100 times real speed. More than one lap can
be displayed simultaneously, with the second lap’s data
displayed with black needles, bars and steering wheel.
In addition to displaying the logged parameters, the
MoTeC i2 software can also calculate data from the logged
information. It does this by using maths expressions either
supplied in the software or added by the user. For example, Oversteer (ie, the car yawing because the rear of the
car is sliding laterally) is calculated using the following
expression:
Oversteer (rad) = smooth(choose(‘Corr Speed’[km/h]<50, 0,
sgn(‘G Force Lat[m/s/s])*((‘Vehicle Wheelbase’[m]*’G Force
Lat[m/s/s]/sqr(‘Corr Speed’[m/s])) – sgn(stat_mean(‘Steered
Angle’[rad]*’G Force Lat’[m/s/s]))*’Steered angle’[rad])), 0.2)
This calculated data can then be graphed along with
the logged data. For example, here mid-corner the car is
showing a calculated -3.9° of oversteer with a measured
steering angle of 7.8°, a speed of 75.5km/h and a throttle
position of 49.7%.
84 Silicon Chip
siliconchip.com.au
labelled (eg, “Turn 1” and “Straight 4-5”), allowing the
analysis of data to proceed, based on where on the track
the car was at the time.
Other Functions
In addition to the screens shown here, the i2 software
can:
• Draw scatter graphs (for example, graphing brake
pressure versus front/rear brake bias - a technique that
shows if the dual master cylinder brake pedal mechanism
is flexing);
• Correlate imported video imagery with the movement of the car around the track (in addition to showing
the driver in action, video cameras can be used to examine
suspension arm flexing and adjustable anti-roll bar behaviour);
• Draw histograms for any of the logged parameters
(eg showing the time the engine spends at different revs
at full throttle, allowing optimisation of the shape of the
engine power curve for that track).
Conclusion
The days of the driver down-changing too early, overreving the engine and then blaming something else for
the engine failure are well and truly gone. In fact, one can
almost feel pity for the driver who has every single one of
their driving actions analysed in such detail! However, to
be competitive in any high level motor sport, logging and
analysis software has become vital.
Another calculated value is damper (shock absorber)
velocity expressed, in mm/s. This is calculated by the
software on the basis of damper position and time and is
most usually displayed in histogram form. The histogram
bars correspond to 10 mm/s increments and both bump
and rebound velocities are shown. A division between high
speed and low speed damper movements is set that matches
the damper valving characteristics (eg, 25 mm/s) and then
analysis is possible of the proportion of time each damper
spends moving at the different velocities in both low speed
and high-speed bump and rebound. Specialist race car
engineers suggest that symmetrical suspension damper
velocity histograms (as here) show the correct bump and
rebound damper settings are being used. This information
is impossible to collect and view without sophisticated data
logging and analysis software.
siliconchip.com.au
Data is logged and later analysed in all racing cars. Making
sense of the collected information is the task of the race car
engineer working with a dedicated analysis software package.
The MoTeC I2 software shown here is available as a free
download from http://software.motec.com.au/release/
The software comes with sample logs.
MoTeC Pty Ltd. Phone: (03) 9761 5050.
Website: www.motec.com
The previous displays show a circuit racing car but data
analysis is equally as important with a drag car. This screen
grab shows data from a drag racing car at the Willowbank
track in Queensland. Engine RPM and temperatures of the
eight exhausts are shown on the graphs, while the righthand column again shows other data that was logged.
This includes a longitudinal acceleration of over 4g(!), a
supercharger boost pressure of 36 psi and a fuel flow of
just under 44 US gallons/minute. (Note the facility of the
software to mix and match units; purists may hate it but
it’s the way of the racing world.) At this stage in the run
wheel speed was only 33.5km/h; just over five seconds
SC
later it was 446km/h!
August 2006 85
SILICON
CHIP
If you are seeing a blank page here, it is
more than likely that it contained advertising
which is now out of date and the advertiser
has requested that the page be removed to
prevent misunderstandings.
Please feel free to visit the advertiser’s website:
www.altronics.com.au/
SILICON
CHIP
If you are seeing a blank page here, it is
more than likely that it contained advertising
which is now out of date and the advertiser
has requested that the page be removed to
prevent misunderstandings.
Please feel free to visit the advertiser’s website:
www.altronics.com.au/
SILICON
CHIP
If you are seeing a blank page here, it is
more than likely that it contained advertising
which is now out of date and the advertiser
has requested that the page be removed to
prevent misunderstandings.
Please feel free to visit the advertiser’s website:
www.altronics.com.au/
SILICON
CHIP
If you are seeing a blank page here, it is
more than likely that it contained advertising
which is now out of date and the advertiser
has requested that the page be removed to
prevent misunderstandings.
Please feel free to visit the advertiser’s website:
www.altronics.com.au/
Multi-Throttle Control
Are you into PC flight simulators? Find the control
your typical controllers give you just a bit less than
satisfying? Take a step up: add this very simple multithrottle controller and start flying with the big boys . . .
T
HIS PROJECT SHOWS how to
construct a “bare bones” throttle
controller for up to four engines.
It is essentially a 4-axis, 4-switch
analog controller, which plugs into
a standard PC games port or can be
expanded for those modern computers without such, to connect via a
USB port.
90 Silicon Chip
Make no mistake, Flight Sims (FS)
and many Flight Combat Games (FCG)
are complex software.
You’ll typically learn to master them
by throttling all engines (assuming
a multi-engine plane!) by the same
By Robert Gott
amount at the same time.
But as any pilot will tell you, that
is simply not realistic. You need to
be able to control the engines individually.
Before we proceed further, a few
words about controlling Flight Simulators are appropriate. A twist-handle
USB joystick (4 axis – Aileron, Pitch,
siliconchip.com.au
Rudder & Throttle) is absolutely essential even for the beginner. Taxiing,
take-offs and landings are pretty miserable without proper rudder control
on the joystick.
Don’t be tempted to buy cheap basic
joysticks. You’ll regret it! Common
good brands are Microsoft, CH, Saitek
and Logitech. All of these now use the
USB port.
Assuming one has mastered the
basics of flying using one throttle
control that varies all engines’ RPM
simultaneously, it’s time to now proceed to individual throttle control.
Unfortunately, though, that control
is not available on typical joysticks.
That’s where this project comes in.
It allows the “pilot” (you!) to vary the
individual engine speed (measured in
revolutions per minute or RPM) using
Microsoft’s proprietary Control Panel
settings in Windows. It would be wonderful if Microsoft would embody say
eight or sixteen arbitrary “axis” and
the same number of “buttons” in their
next incarnation of Windows but for
the moment 4 + 4 is the best available.
Proprietary Throttle Quadrants
such as CH USB 300-133 (shown
above) use their own software but the
cost is almost as high as the planes fly
– circa US$150! With this project, we
will achieve a modicum of reasonable
results – but much cheaper.
In fact, we believe it should cost no
If you have the readies, this
commercial throttle unit (CH
USB 300-133) is regarded as
one of the best around. Ours is
just a tad simpler and a whole
lot less expensive!
more than about $25 or so: eight dollars for the four pots, a similar amount
for the four switches and the balance
for a box to put it all in. You’ll also
need a multi-way cable with D15 connector but these can often be sourced
from the junk box. OK, if you want to
go all out and add knobs and a fancy
label, you might stretch it to $25 – but
not much more.
The games
Many of the older excellent games
like the renowned “European Air
Wars” by Microprose, “Battle of Britain” and “Red Baron 3D” by Sierra
will not now install or run properly
in Windows XP Pro, the author’s O.S.
Sometimes a game will run in Windows “Compatibility” mode. (Right
click desktop games icon>PROPERT
IES>COMPATIBILY>follow prompts.)
Other software called “Wrappers”
try to emulate the original game playing software, not very successfully
in the author’s experience. The list,
which is by no means exhaustive,
gives some hints and where this
project will work, the author has
personally tested the games using
Multi-Throttle.
PC Hardware and software.
My PC is a four-year-old AMD
for PC Flight Sims
siliconchip.com.au
August 2006 91
S1
ENGINE 1
100k LIN
S2
ENGINE 2
100k LIN
LIGHT GREEN
8
7
GREEN
6
5
PINK
4
MUSTARD 3
2
RED
1
15
14
13
BROWN/
BLACK
BLACK
12
11
Construction
GREY
10
9
VIOLET
S3
ENGINE 3
100k LIN
S4
ENGINE 4
100k LIN
PC GAMES PORT
(D15 PLUG)
BROWN
SC
2006
FLIGHT SIM MULTI THROTTLE controller
Control up to four engines on a multi-engine flight sim plane. It plugs into
your PC’s games port (or USB port via a USB adaptor)
XP1800+, with 768MB RAM, 64MB
GF3 Ti 200 AGP with games port,
USB 1.1 and USB 2.0 sockets. The
joystick is a
Microsoft Sidewinder Precision Pro
USB (Twist stick rudder control) run-
ics (no separate graphics card) may
struggle to play the named games
anywhere near fully optioned. Modern
PCs are better, but even Celeron and
Sempron PCs with integrated graphics may use main swap memory and
struggle similarly with the latest FS.
To be realistic any PC older than
a PentiumII 350MHz would not do
justice to many, if any, of the games
listed.
ning Windows XP Pro with SP1 and
DirectX (9c). The multi-throttle unit
has NOT been tested with Windows
98SE but the Joystick configuration in
Control Panel may work.
Note: Older PCs with integral graph-
There’s not much to this – no PC
board, no difficult wiring. That’s
mainly because there are few “components” as such – just the four
switches and four pots wired to the
D15 connector.
Mount the hardware first because
the wiring simply connects between
it. Any plastic box of 130(W) x 70(D)
x 45mm(H) or larger will suffice.
Position the circular potentiometers
and switches on the lid allowing for
the size of chosen knobs and enough
clearance for your fingers. Mark out
and drill appropriate holes, four each
for the pots and switches.
Drill one hole in the preferred end
of the box for the 15 core cable. It’s
best to secure the cable with a cable
clamp so you’ll need an extra hole for
this. If you normally use a joystick
with your right hand, the controller
Parts List:
Flight Sim Multi Throttle
1 ABS box, approx. 130 x 70 x
45mm
4 100kW linear pots
4 knobs to suit with index lines or
pointers.
4 SPST toggle switches, (low
voltage)
1 plastic cable clamp
1 10mm M3 screw, washer and
nut
1 1.8m D15 male to female game
cable extension.
(eg, Altronics P1765)
(or 2m D15 PC joystick extension
cable (eg Maplin* TA50E <at>
£4.99)
1 D15 to USB Converter if required. (eg, Maplin* UA22Y <at>
£8.00)
Possible alternative suppliers:
www.wyntec.com.au or
www.trianglecables.com
*(www.maplin.co.uk)
92 Silicon Chip
Here’s a view inside the “opened out” controller
siliconchip.com.au
Flight Simulators and Combat Flying Games
GAME/Publisher
Windows
Version
API: Direct X
OpenGL, 3DFX
CPU: Pentium or Playable
equiv AMD
MultiEngines
2 or 4
Tested With
Multi-Throttle?
Comments
FS 2004 Microsoft
XP
DX 9.0c
P4 or AMD64
2 and 4
No but should be
OK
Should work OK. Needs latest mid
price graphics card minimum.
FS 2002 Microsoft
98 ME XP
DX 8.0a
P4
2 and 4
Yes
Needs good graphics card, plenty
of memory.
Wings of War Gathering
98 ME XP
DX 9.0
P4 1.8G
None
Yes n/p
*
Geforce 4 graphics. Pity 2 engines
not playable.
B17 Flying Fortress Atari
95 98 ME XP
DX 8.0
P3 800
2 and 4
Yes
Fantastic game with realistic crew.
CFS 3 Microsoft
98 ME XP
DX 8.1
P4
2
Yes
Battle for Europe
CFS 2 Microsoft
95 98 ME
DX 7.0a
P3 600
2
Yes
Pacific theatre
CFS 1 Microsoft
95 98
DX 6.0
P3 600
None
Yes n/p
*
European theatre. Will not work
with MultiThrottle connected to PC.
FS98 Microsoft
95
DX 5.0
P2 350
2
No
IL2 Sturmovik,
Forgotten Battles, Ubisoft
98 ME XP
DX 8.1
OpenGL
P3 800
2 and 4
Yes n/p
*
Pentium III 800 or above Geforce 3
or 4 or above.
IL2 Sturmovik Ubisoft
98 ME XP
DX 8.1
P3 600
2
Yes n/p
*
Geforce 2 card or above.
Flanker 2
98SE
?
P4
2
No
Screen lock-up. Try XP
F18E
98SE
DX 6.1
P3 600
2
No
Will NOT play in Win XP
F22
98SE
?
P3 600
2
No
Demo played OK
Red Baron 3D
95 98SE
Not XP
DX 5.0 3DFX
P2 350
None
Yes n/p
Run in compatibility mode for
Win 98SE
European Air Wars Microprose
98SE
3DFX
DX 6.0
P2 350
2
Yes n/p
*
Will play in Direct X
Crimson Skies Microsoft
95 ME XP
DX 7.0a
P3 800
2
Yes n/p
NOT Win 98 or SE
Flight Unlimited II
98SE
OpenGL
P3 800
2
No
Not Win XP
Battle of Britain
98SE
?
P3 800
?
No
Will NOT play in Win XP
NOTES
N/P = Not possible as tested by author:
MultiThrottle configuration is NOT possible in this game.
API = Application Programme Interface; A software written for
games. Note: The minimum version of Direct X required is indicated.
Sometimes the game plays only or best in that version, but as the latest
version is supposed to be backward compatible, ALWAYS use the latest
version first. Most Microsoft games play with Direct X 9.0c, the latest
version at the time of writing. The other two common APIs are 3DFX
Glide and OpenGL.
CPU = Intel or AMD minimum recommendation to play reasonably well
optioned.
MEMORY: 512Mb absolute minimum.
siliconchip.com.au
OPERATING SYSTEM (OS): Although Windows 95 is listed above it
must be ORS2 to work with USB. Quite frankly Win95 is now so old
hat that it should be avoided where possible. Win 98SE much better.
Win98Me quirky!
ENGINES: By implication, ALL games listed have SINGLE engine
aeroplanes. Only those games listed in the “Multi-engines” column
have flyable aircraft.
* Do NOT connect the MultiThrottle unit to the PC as it causes wrong
configuration, so I found – and the joystick does not get the correct
assignments. (If you really must stick your neck out, install and try
the game without the MultiThrottle first. If everything works OK then
plug in MultiThrottle. Should you not be able to juggle the assignments
satisfactorily, unplug MultiThrottle, uninstall then reinstall game. You’re
on your own!)
August 2006 93
Calibration.
ENGINE 1
100k LIN
ENGINE 2
100k LIN
ENGINE 3
100k LIN
S2
S3
S1
ENGINE 4
100k LIN
S4
5
1
8
15
D15 PLUG
9
12
Here’s the complete wiring
diagram – with a matching photo
below to make wiring really simple!
Check and double check your wiring and if satisfied, plug the D15 into
the games port of your computer when
it is turned off. When you switch on
your PC – assuming Windows XP
Home or Pro – it will detect new
hardware.
You may follow the prompts but the
preferred method is to CANCEL the automatic install and proceed as follows;
CONTROL PANEL>GAME CONTRO
LLERS>ADD>CUSTOM>JOYSTICK>
AXES 4>BUTTONS 4>CONTROLLER
NAME (what you want to name the
controller is up to you – I called mine
RobertMultiThrottle)>OK.
Reboot the PC and ensure that the
new controller is listed in GAME
CONTROLLERS and its STATUS is
OK. We assume your joystick or any
other controller attached shows STATUS OK also.
So far so good! Now calibrate the
MultiThrottle exactly the same as you
would a joystick.
As previously mentioned don’t be
too worried whether clockwise rotation of your pots give exactly what
you expect.
It is important that the full excursion of the axes is recognised and
saved. Similarly, the switches need to
be recognised as the relevant 1,2,3,4.
Flight Sim Assignments
is best placed with the cable at the
left side for use with your left hand.
Mount the components and push on
the indexed knobs.
Next prepare the cable using the
commercial games extension cable.
WARNING: Before you cut the cable,
use a test meter or battery and lamp
to check out that all 15 conductors
are wired.
Ensure that you chop off the unwanted end(!). Leave about 250mm
cable connected to the socket as you
may find a use for the discarded bit,
like wiring wire!) and bare back a
generous 150mm or so outer sheath.
Strip off 3mm of insulation on all the
conductors.
Now trace out which colours go to
which pins on the D15 games port
plug.
The colours shown on the circuit
and wiring diagrams were those on
94 Silicon Chip
the prototype but we cannot guarantee
all cables/connectors will be the same.
So double check which coloured wire
goes to which pin and if necessary,
correct the circuit and wiring diagrams
to avoid later confusion.
The circuit is basically standard
game port wiring without using the
Midi terminals, therefore only 10
wires out of the 15 are employed.
The five D15 pins not connected
are pins 5, 8, 9, 12 & 15). Identify
which wires go these pins and chop
off the bared 3mm on the 5 unwanted
conductors to minimise the chance of
short circuits.
Anchor the cable inside the box
with a plastic cable clamp then solder the wires as shown in the circuit
diagram and wiring diagram.
The logical designation of pots and
switches is left to right equals port
(left) to starboard (right) engines.
It is beyond the scope of this simple
project to give more than a few hints.
Most who “fly” the games listed above
will have some if not good experience
of changing keyboard and joystick
assignments. It is largely a matter of
experiment. What follows is mainly
for beginners.
When a game is installed it usually
loads its default or standard CONFIGURATION of controls. Unless you tell it
otherwise, often the joystick will be
detected as the primary controller.
However with other controllers
connected, when assignments are
altered in “preferences” or “options”,
to alleviate the frustration of setting
up every time the game is played,
many games allow you to SAVE the
CONFIGURATION with a new given
name, say Multi-Throttle. If this is
not automatically the default when
you next play the game, then select
it manually.
USB Operation
For those PCs without a game port,
siliconchip.com.au
Flying a B17
This is chosen to demonstrate assignments as it is typical of
the user-friendly type icon based games. (ie, non-menu type) It is
also a very cheap re-released game with four propeller engines.
Actual crew can be seen and moved around in the fuselage. A truly
exciting game if you are not a die-hard purist simmer! Using the
default assignments, the MultiThottle unit switches appear to work
immediately as “Select Engine 1 - 4”. If not reconfigure as such.
Throttles wired as previously mentioned, clockwise potentiometer rotation gives 100k-0k, which configures in “Engine One
Throttle” = “Axis #1 (X), Controller #2, Normal.” “Normal” means
that with clockwise pot rotation, the propeller increases RPM.
Configure the other three throttles similarly.
Note: Step by step instructions for “Engine One Throttle.” Click
on “Engine One Throttle” and it highlights. In the opposite panel,
click on “Axis”. As it scans rotate the Engine 1 pot fully a couple
of times. This will be detected as shown.
In B17 all propellers turn the same way – clockwise as seen by
the pilot. This is not always the case. Some twin engine aeroplanes
have the propellers turning in opposite direction to counter the
torque effect. With a Lancaster bomber (A FS2004 add-on) the
pull to port must be countered by opposite rudder or decrease
starboard revs – not something you would do with maximum
bomb load!
In the early days getting B17 engines to start caused the author
great frustration. At the bottom RHS of the game screen is an
icon – a picture (Gif) – of a PC. This means that the PC is on AUTOMATIC and controls the flight. Press keyboard key “M” and the
icon changes to a hand meaning – you’ve guessed it! – MANUAL
control. At this point in external view, select Engine 1 on MultiThrottle unit, rpm minimum, then press key “A.”
From this point B17 controls the start procedure beginning
“Master Switch ON”, etc, finally “meshing” (cranking!) and away
she goes. To stop an engine, again select the appropriate switch
on MultiThrottle, then press key “S.” B17 controls selected engine
shut down. Feathering, so that propeller stops windmilling, press
key “D”. Now you are cooking with gas!
FS2002
This is a much more sophisticated simulator used for “real life”
flying rather than a game. (FS2004 is similar) They are not as user
friendly as other icon based set-ups but their menu type assignments are very comprehensive.
With a little trial and error the MultiThrottle unit is fairly easy to
configure. The basic FS2002 has two and four engine jet engine
planes but no such prop models. The Lancaster bomber as previously mentioned is an add-on.
Rather than B17’s (Fig 7) style, Microsoft uses “tabs” and “drop
down menus” to choose between Joystick or Keyboard assignments. It also has a separate window for setting sensitivities and
deadbands, and many more keyboard commands.
Observe “Joystick type” in Fig 8. Note that RobertMultithrottle
has been selected. In the “Assignment list” Microsoft specifies a
throttle as an axis. Click on “Engine 1 Throttle axis.” It highlights.
Click on “Change assignment.” Rotating Throttle 1 potentiometer
will cause x-axis to be recognised. Save the assignment. Engine
2, 3, 4, are recognised as y-axis, Throttle and Rudder (not visible
in Fig 8) respectively. It may be necessary to use the “Reverse”
mode (shown checked - an X within the box) to get correct throttle
increase (clockwise=increase RPM).
simply plug the Multi-Throttle unit
15 pin “D” plug into a USB Converter
“D” socket, then plug the converter
USB plug into any PC USB port. The
green object on the left side of the desk
(opening photo) is such a converter. It
happens to be from Maplin (UK) but
they are also often seen on eBay and
other places on the ’net.
siliconchip.com.au
Set the converter to MODE 3 before
booting the PC.
Conclusion.
The MultiThrottle Controller gives
added interest to Flight Sims at little extra cost and may overcome
the problem of ‘no games port’. The
Multi-Throttle unit may work with
other flying games but ask the retailer
to verify before purchase or check the
Websites.
I’m not an expert on flight Sims. I am
still grappling with the complexities
of FS! The ability to control engine
RPM individually has given me a real
buzz. And make flying that much more
SC
pleasurable. Happy simming!
August 2006 95
CIRCUIT NOTEBOOK
Interesting circuit ideas which we have checked but not built and tested. Contributions from
readers are welcome and will be paid for at standard rates.
Infrared remote
extender
This project sprang from the need
to be able to remotely control audiovisual equipment placed inside
cupboards. RF-based commercial
units such as those used for home
theatre were found to be overkill for
this application.
The circuit is based on a commonly available infrared receiver
module (IRX1) and a PIC12F675
microcontroller (IC1) – see circuit.
Most infrared standards specify a
nominal 38kHz carrier signal for
data transmission, which the module receives and demodulates.
Digital data output
Here’s how to install the parts on the IR extender PC board.
96 Silicon Chip
The digital data output from the
module is fed into GP2 (pin 5) of
the PIC micro, where it’s received
by the PIC program and duplicated on output GP1 (pin 6). This
flashes the “Signal” LED to give a
visual indication that the extender
is receiving the remote control’s
transmissions.
In addition, the program regenerates the nominal 38kHz carrier and
modulates this with the incoming
signal on output GP0 (pin 7). This
drives the bases of transistors
Q1-Q3, which in turn drive three
infrared LEDs positioned near the
AV equipment.
Note that the infrared receiver
has an open-collector output that
requires an external pull-up resistor.
siliconchip.com.au
; IR Remote Repeater by Alex Sum
; V1.03A 11/12/2005
In this design, the pull-up is provided by enabling the PICs internal
port pull-up on the GP2 input.
Power for the unit is sourced from
a 9-12V DC plugpack. A conventional 3-terminal regulator (REG1)
reduces this to 5V to power the
extender circuit. Diode D1 provides
protection against accidental reversal of the power leads.
Source code
The panel at right lists the assembly language source code for the
program. It’s a relatively short piece
of code and a useful example for
those learning about PIC microcontroller programming. The program
and an accompanying flowchart is
available for download from the
SILICON CHIP website in a file named
“IRREPEAT.ZIP”.
A PC board for the infrared extender is available from RCS Radio
– phone (02) 9738 0330 and quote
board number RCS 5584s. Follow
the overlay diagram to construct
the board. The DC power connector (CON1) is available from Jaycar
Electronics (Cat. PS-0520), as are
the 3.5mm phone sockets (CON2CON4, Cat. PS-0123).
The infrared receiver module
is available from both Jaycar (Cat.
ZD-1952) and DSE (Cat. Z-1955),
while the PIC12F675 and its 16MHz
resonator (X1) can be obtained from
MicroZed (see www.microzed.com.
au). Once built, it can be housed in
an ABS project case.
list
p=12f675
;list directive to define processor
errorlevel -302
;suppress message 302 from list file
#include <p12f675.inc>
;default processor specific header file
__CONFIG _CP_OFF & _WDT_OFF & _BODEN_OFF & _MCLRE_OFF & _PWRTE_ON & _HS_OSC &
_CPD_OFF
; Constants
Delay equ
; Data
; Code
ORG
0x20
Statevar RES
Cntr
RES
ORG
goto
ORG
retfie
ORG
1
1
0x00
MCUINIT
0x04
0x08
MCUINIT:
BANKSEL ANSEL
Clrf
ANSEL
clrf
VRCON
movlw b’00111100’
movwf TRISIO
movlw b’01001000’
movwf OPTION_REG
bsf
WPU,2
BANKSEL GPIO
clrf
GPIO
movlw 0x07
movwf CMCON
movlw 0x00
movwf statevar
sigwait:
btfsc
goto
movlw
movwf
bsf
cloop:
movlw
movwf
movf
xorlw
movwf
btfsc
goto
gp0low:
bcf
goto
INPUT
sigwait
0x00
statevar
LED
Delay
cntr
statevar,w
0x01
statevar
statevar,0
gp0high
t2now:
btfss
goto
LEDoff:
bcf
signal:
bcf
goto
btfss
goto
goto
end
;RAM area
;carrier output toggle
;counter for T/2
;reset vector
;interrupt vector
;return from interrupt
;program starts here
;bank 1
;GP0-3 as digital I/O
;turn off VREF
;GP0-1 as outputs, GP 2 input
;weak pull up enabled, rising edge
;assign PS to WDT 1:1
;GP2 weak pull up enabled
;Bank 0
;turn off comparator
;read GP2 and check for Z
;no wait until Z
;make sure statevar is zero
;turn LED on
;(52-n)/y*dly01
;toggle state
Alex S
is this m um
on
winner th’s
Peak At of a
las
Instrum Test
ent
IRLED
dly01
gp0high:
bsf
IRLED
dly01:
decfsz cntr,F
goto
notyet
notyet:
siliconchip.com.au
;should be (52-n)/y*dly01
;y is number of instructions in dly01
;n is overhead in cloop etc
;IR LED on GP 0
;Status LED on GP 1
;Input on GP 2
#define IRLED GPIO,0
#define LED
GPIO,1
#define INPUT GPIO,2
Infrared LEDs
The infrared LEDs can be mounted on a small piece of prototyping
board and connected with 3.5mm
mono phone plugs and 2-core
cable. The author used both 3mm
(Jaycar Cat. ZD-0100) and surface
mounted (Altronics Cat. Y-1094)
LED varieties.
The SMD variety are particularly useful in this application, as
they can be mounted on a tiny section of circuit board and attached
to the infrared receiver window
of the AV equipment with doublesided tape.
Alex Sum,
Eastwood, NSW.
.7
;reach T/2 yet?
INPUT
cloop
;yes T/2 now so check input again
LED
;turn off LED, wait for more
IRLED
sigwait
;make sure IR is off as well
INPUT
dly01
LEDoff
;check input again
August 2006 97
Circuit Notebook – Continued
PICAXE battery
protector
While many low-battery cutout
circuits have been published in the
pages of Circuit Notebook before,
this design is a little different. Its
distinguishing feature is the ease
with which the threshold voltages
can be trimmed, thanks to the use
of a PICAXE-08M microcontroller.
Mains-derived
timebase
This simple circuit shows how
to derive a 1Hz timing signal from
the 240VAC mains. It would be useful in applications requiring time
synchronisation or could simply be
used to drive a clock circuit.
A small 12VAC transformer feeds
an optocoupler (OPTO1) via a 1.5kW
current-limiting resistor, such that
each positive half-cycle causes
98 Silicon Chip
It can be built to work with 6-24V
batteries and uses a MOSFET to
switch the load.
Power for the circuit is provided
by an LM2940CT-5 +5V regulator
(REG1). A low dropout type was
chosen so that the circuit can operate with 6V batteries.
The battery voltage is monitored
via one of the A-D converter inputs
(ADC4) of the PICAXE (IC1) after be-
its internal LED to conduct. The
negative half-cycles are shunted by
diode D1. The output of the optocoupler is a square wave of 50Hz,
which is applied to the clock input
(pin 10) of a 14-bit binary counter
(IC1).
Outputs O0, O3 and O4 of the
counter are ANDed by IC2a and then
inverted by IC2b. As a result, when
all three of the counter’s outputs go
high, equating to a count of 50, the
output of IC2b goes high, clocking
ing divided down by resistors R1 &
R2. When this voltage drops below
the programmed lower threshold,
the BASIC program sets a “flag”
to indicate that the battery needs
recharging/replacing. This flag is
stored in non-volatile memory, so
that its state is remembered even if
power is disconnected.
Next, the program writes a high to
output2 to light the LED and a low
to output1 to turn off the MOSFET
(Q1) and interrupt load current.
The microcontroller then continues
to monitor the battery voltage and
when it rises above the programmed
upper threshold, the MOSFET is
switched on again and the LED is
turned off.
A bypass facility is also provided
for testing. When the program
detects a low on input3 (ie, the
“bypass” link is installed), the load
is connected regardless of the battery voltage. The LED then flashes
continuously to indicate bypass
mode. Power must be removed to
exit this mode.
Note that a logic-level MOSFET, such as the MTP3055VL, is
required to switch the load. Other
types of MOSFETs may not be
fully enhanced by the low (5V)
the J-K flipflop (IC3).
The flipflop is wired to toggle
with each input clock pulse, so
its output is a square wave with a
one-second high/one-second low
period.
As is usual practice, 100nF capacitors should be connected between
the power and ground pins of each
IC and unused logic gate inputs
should be grounded.
Gary Smith,
Montrose, Tas. ($30)
siliconchip.com.au
Listing 1: PICAXE Battery Protector
' Low Battery Cutout
' PICAXE-08M
symbol lo=296
symbol hi=503
'low limit (turn off voltage)
'high limit (turn on voltage)
main:
if pin3=0 then bypass
read 0,b2
'bypass for testing or adjustment purposes
'read recharge flag from memory into variable b2
main2:
readadc10 4,w0
if w0>lo and w0<hi then check
'flag set
if w0<lo then shutdown
if w0>hi then start
start:
high 1
low 2
if b2=1 then clearflag
'read ADC on input4 into variable w0
'if w0 is between lo and hi then check if recharge
'if w0 is less than lo then turn off (shutdown)
'if w0 is greater than hi then turn on (start)
'switch output on
'switch off RECHARGE LED
'if recharge flag set then clear flag
pause2:
pause 1000
goto main2
'pause 1s before next reading
'loop
shutdown:
low 1
high 2
'switch output off
'switch on RECHARGE LED
gate drive voltage, with the result
being reduced voltage to the load
and potential overheating of the
transistor.
The values of resistors R1 and
R2 are determined according to
the maximum battery voltage. In
practice, their division ratio must be
chosen so that the maximum voltage
at the input to the PICAXE never
exceeds 5.0V. Higher voltages may
if b2=0 then setflag
pause 50
low 2
pause 1000
goto shutdown 'loop
clearflag:
let b2=0
write 0,b2
goto pause2
'if recharge flag not set then set flag
'pause 50 ms
'switch off RECHARGE LED (flashes LED)
'pause 1 second
'clear recharge flag
'store value in memory
'loop back into start
setflag:
let b2=1
'set recharge flag
write 0,b2
'store value in memory
goto shutdown 'loop back to shutdown
check:
if b2=0 then start
'if recharge flag not set go to start
goto shutdown 'else go to shutdown
bypass:
high 1
'switch output on
flash:
high 2
pause 250
low 2
pause 250
goto flash
'switch on RECHARGE LED
'pause 250 milliseconds
'switch off RECHARGE LED
'pause 250 milliseconds
'loop
damage the microcontroller.
For best results, keep the combined values of R1 & R2 at around
10kW. Note that if the battery is to
be charged in circuit, the higher terminal voltage that occurs towards
the end of charge must also be taken
into account.
Finally, the “lo” and “hi” values
in the program must be set to suit
your battery pack and divider ratio.
Suitable values are easily determined by feeding the circuit with
a variable voltage while monitoring
the w0 variable using the debug
command.
Details on how to use the debug
command to monitor output from
the readadc10 command are included in the PICAXE manual.
Terry Mowles,
via e-mail. ($40)
Contribute And Choose Your Prize
As you can see, we pay good money
for each of the “Circuit Notebook” items
published in SILICON CHIP. But there are
four more reasons to send in your circuit
idea. Each month, the best contribution
published will entitle the author to
choose the prize: an LCR40 LCR
meter, a DCA55 Semiconductor
Component Analyser, an ESR60
Equivalent Series Resistance
Analyser or an SCR100 Thyristor &
Triac Analyser, with the compliments
of Peak Electronic Design Ltd – see
siliconchip.com.au
www.peakelec.co.uk
So now you have even more reasons
to send that brilliant circuit in. Send it
to SILICON CHIP and you could be a
winner.
You can either email your idea to
silchip<at>siliconchip.com.au or post it
to PO Box 139, Collaroy, NSW 2097.
August 2006 99
Circuit Notebook – Continued
Automatic daytime
running lights
The safety benefits of using vehicle headlights during daylight hours
is now well proven, with increasing
numbers of vehicles including this
feature as standard equipment.
This add-on design provides a
low-cost method of automatically
activating the low-beam headlights
when driving. With only a little
added complexity, a useful delayed switch-off function has also
been included that will light your
way when you leave the vehicle
at night!
A fused feed from battery positive
powers the low-beam lamps via the
contacts of relay RLY1 and a 35A
bridge rectifier (BR1). The series
100 Silicon Chip
diodes reduce the voltage applied
to the lamps, which substantially
increases filament life for only a
small reduction in brightness.
Note that the bridge must be a
metal-cased type and needs to be
bolted to a large flat metal surface
for heatsinking.
Power for the relay coil is sourced
from the ignition switch via transistor Q2. This transistor is controlled
by the parking brake switch, so that
when the parking brake is applied,
Q2 is switched off and vice-versa.
A second transistor (Q1) simply
inverts the signal from the parking
brake switch for use with a negative
switched input.
To use with a positive-switched
input (ie, warning lamp and parking
brake switch transposed), simply
omit resistor R1 and transistor Q1,
as indicated on the circuit.
The relay coil finds ground
through the high-beam lamp filaments. This causes the relay to
switch off when high beam is
selected, thus preventing simultaneous operation of both high and
low beams.
A 555 timer (IC1) wired as a
monostable provides the delayed
switch-off function. To activate
it, switch the headlights off, on
for a moment then off again. This
triggers the 555, which drives pin
3 high to energise the relay. After
about 29 seconds, the 555 times out,
switching the relay off and removing power from the circuit.
Graeme Duncan,
Otago, Tasmania. ($40)
siliconchip.com.au
supply terminals.
If you’d like to
test the unit before
connecting your
(exp ensive) LED,
temporarily connect a 10W 5W resistor in its place.
Apply 9-24V to the
input and measure
the voltage drop
across the 10W resistor; it should remain constant at
about 3.2V.
Note that not all
chargers have an output filter capacitor installed. Typically, this is a
220mF 10V or 16V electrolytic unit.
To save a few cents, the manufacturers sometimes leave this component
out, relying on the mobile’s battery
to perform the filtering task.
If the 220uF capacitor is missing
from your charger’s PC board, it
should be installed before the supply is used. Use a 25V rated part if
you intend to power the unit from
more than 16V. This allows for accidental disconnection of the LED
with power applied, where the
output voltage will rise close to the
input voltage.
Finally, data on the MC34063 can
be downloaded from www.onsemi.
com and a useful development aid
is to be found at www.nomad.ee/
micros/mc34063
Editor’s note: we described an
efficient 12V fan speed controller,
also based on mobile phone chargers, in the January 2005 edition.
Dave Sime,
Hughes, ACT. ($35)
Fig.1: a typical switchmode battery
charger as used in mobile phones.
Cheap 1W Luxeon
LED driver
Step-down switchmode power
supplies are often used in preference to their linear counterparts in
applications where there is a large
input to output voltage differential.
Such is the case when driving Luxeon 1W Stars and their derivatives
from a 12V DC source, which is the
focus of this circuit.
Mobile phone chargers based on
the MC34063 switchmode controller IC are easily modified to operate
as a simple constant-current source,
suitable for powering a single 1W
white or blue LED, or two 1W red
LEDs in series. Defunct mobile
phone chargers are readily available
at local markets and on ebay.com.
au for a few dollars.
These units are quite easy to pull
apart. First, unscrew the metal nipple from the end and remove the
fuse, then prise off the metal collar
that holds the two halves together.
You can then easily separate the
two halves and extract the circuit
board.
The circuit shown in Fig.1 is
typical of most chargers, with some
including a few extra components
Fig.2: how to modify the
charger circuit to drive a
1W Luxeon Star LED.
siliconchip.com.au
for indicator LEDs. Resistors R1 and
R2 set the regulated output voltage,
which can be calculated using the
formula VOUT = 1.25(1 + R2/R1).
This will result in a 7.1V output
using the values shown.
Because the MC34063 strives to
maintain a constant 1.25V across
R1, we can replace R2 with our 1W
LED (Fig.2) and select a much smaller value for R1 using the formula
I = 1.25/R1. Using a value of 3.9W,
about 320mA of regulated current
will flow through the LED.
To modify the charger, start by
removing R1 and R2. Note that
the labelling of the resistors on the
circuit board will probably be different; use your meter or follow the
tracks on the board to identify the
resistors of interest.
Replace R1 with a 3.9W 1W resistor and wire the Luxeon Star into
the R2 position using medium gauge
hook-up wire. Keep the wire length
as short as possible and make sure
that you’ve connected the anode
(+) to the positive output and the
cathode (-) to the junction of
R1 and R2. Do not connect
anything to the metal heatsink of the Star; this must
be isolated from the power
It’s quite easy to modify a discarded mobile
phone charger to drive a 1W Luxeon Star LED.
August 2006 101
mini
T h eremin
Mk.2
PART 2: By JOHN CLARKE
B
Last month, we described the
features of our new Theremin and
gave the full circuit details. This
month, we show you how to build
it and describe the adjustment
procedures.
102 Silicon Chip
UILDING THE MINI THEREMIN
is straightforward, with virtually
all parts (except for the loudspeaker
and switches S1 & S2) are mounted
on a PC board coded 01207061 (188
x 103mm). This is housed in a plastic
UB2 utility case measuring 197 x
113 x 63mm.
Fig.5 shows the assembly
details. Begin by carefully
checking the PC board
for any defects (eg,
shorts between tracks
or broken tracks). Check
also that all the hole sizes are correct
for the various parts. In particular,
siliconchip.com.au
Fig.5: install the parts on the PC board and complete the wiring as shown here. Note that the pitch antenna
lead should initially be connected to point “X” (near T2), so that the equalising coil is bypassed – see text.
check the hole sizes for the 6.35mm
jack sockets, the DC power socket,
the IF coils and the potentiometer
mounting holes and redrill the holes
siliconchip.com.au
to a larger size if necessary.
Note also that the corners of the PC
board need to have cutouts as shown
in Fig.5, to clear the four corner pillars
in the case. If necessary, these can be
cut using a small hacksaw and carefully filed to shape using a rat-tail file.
Begin the board assembly by installAugust 2006 103
Table 1: Resistor Colour Codes
o
o
o
o
o
o
o
o
o
o
o
o
o
o
o
o
No.
1
10
1
2
4
1
4
6
2
1
2
1
3
1
3
Value
330kW
100kW
47kW
22kW
10kW
4.7kW
2.2kW
1kW
680W
330W
220W
150W
100W
39W
10W
ing PC stakes at the eight external
wiring points, test points (TP1 & TP2)
and the GND point (adjacent to VR2).
In addition, PC stakes are used to terminate the leads from the equalising
coil (L1). That done, you can install
all the wire links using 0.7mm tinned
copper wire.
Note that the wire links all have a
12.5mm lead spacing. The assembly
will be much faster if you cut a 12mmwide metal or wooden jig and use this
as a spacer to bend the link leads.
Follow the links with the resistors,
using the colour codes in Table 1 as a
guide to selecting values. It is also a
good idea to use a digital multimeter
to check each resistor before it is
installed, as some of the colours can
be confusing.
The ICs, including the 4-pin optically-coupled LDR (OPTO1), can go
in next, followed by the diodes. Make
Table 2: Capacitor Codes
Value
220nF
100nF
47nF
22nF
10nF
1nF
470pF
330pF
68pF
μF Code
0.22µF
0.1µF
.047µF
.022µF
.01µF
.001µF
NA
NA
NA
EIA Code
224
104
473
223
103
102
471
331
68
104 Silicon Chip
IEC Code
220n
100n
47n
22n
10n
1n0
470p
330p
68p
4-Band Code (1%)
orange orange yellow brown
brown black yellow brown
yellow violet orange brown
red red orange brown
brown black orange brown
yellow violet red brown
red red red brown
brown black red brown
blue grey brown brown
orange orange brown brown
red red brown brown
brown green brown brown
brown black brown brown
orange white black brown
brown black black brown
sure that all these parts are orientated
correctly – OPTO1 goes in with the
dot on its body orientated as shown in
Fig.5 (note: the numbering shown on
the pinout diagram in Fig.4 last month
is incorrect). The capacitors can then
be installed (see Table 2) but watch the
polarity of the electrolytics.
The JFETs and transistors are next
on the list. Note particularly that Q6
is a BC337 while Q7 is a BC327. The
remainder are all 2N-5484 or 2N5485
types – be sure to use the correct type
at each location.
Once those parts are in, the trimpots
can all be installed. Orientate the
top-adjust multi-turn types with the
adjusting screw at top, as shown in
Fig.5. The IF coils can then go in. Make
sure that the black-cored can goes in
the T4 position. The three white-cored
cans go in the T1-T3 positions.
Now install the two 3-terminal
regulators (REG1 & REG2). As shown,
REG1 (7809) is mounted horizontally,
with its metal tab secured to a small
heatsink and to the PC board using a
machine screw and nut.
To do this, first bend REG1’s two
outer leads down by 90° about 8mm
from its body and its middle lead down
by 90° about 6mm away. It can then
be installed along with its heatsink on
the PC board and secured using an M3
x 6mm machine screw and nut, after
which its leads can be soldered.
Note that the leads are soldered last
of all. Do not solder the leads before
fastening the regulator to the PC board,
5-Band Code (1%)
orange orange black orange brown
brown black black orange brown
yellow violet black red brown
red red black red brown
brown black black red brown
yellow violet black brown brown
red red black brown brown
brown black black brown brown
blue grey black black brown
orange orange black black brown
red red black black brown
brown green black black brown
brown black black black brown
orange white black gold brown
brown black black gold brown
otherwise the PC pads may crack or lift
due to stress as the screw is tightened.
No heatsink is required for the 7808
regulator. It simply mounts vertically
with its metal tab towards REG1.
Next, install the 6.35mm jack sockets and the DC power socket. Note
that we have specified high-quality
6.35mm sockets (Jaycar Cat. PS-0195)
here. These have a shorter threaded
bush than other commonly-available
units, which will clear the side of the
case when the PC board is installed.
Note: standard sockets are not suitable since they have a longer bush.
This would protrude through the side
of the box, making it impossible to
install the PC board.
Potentiometers
Before installing the potentiometers, it’s necessary to cut their shafts
to length to suit the knobs. On the
prototype, this meant cutting the
shafts to 11mm. They can be cut using
a hacksaw, with the end of the shaft
secured in a vice.
Having cut the shafts, break off the
locating lug on each potentiometer.
The pots can then be soldered in turn
to the PC board, taking care to use the
correct value at each location.
The speaker/headphone volume
potentiometer at the top of Fig.5 is
the only logarithmic type. It will have
an “A” marking (A = log curve) on its
body (eg, “A10k”). Don’t confuse it
with the 10kW linear pot used for the
Skew control (curve B).
siliconchip.com.au
This is the fully-assembled PC board, ready for installation in
the case. Note the earthing link that’s used to connect the bodies
of the pots together and to the ground stake on the board.
As shown in Fig.5, the pot bodies
are all wired together and connected
to circuit ground. This is done by
soldering a 140mm length of tinned
copper wire along the top of the pot
bodies and then running a short link
back to the GND PC stake.
Note that the anodised coating on
each pot body will need to be scraped
away at the soldering points.
Earthing the pot bodies helps prevent tuning changes due to capacitance effects when your hand touches
the adjusting knobs. The plastic knobs
also help to prevent tuning changes
so be sure to only use plastic knobs.
Once the pots are in, LED1 can be
installed. Take care with its orientation – its anode lead is the longer of
the two). Note that the LED should be
mounted at full lead length so that it
can later be bent over to pass through
its matching hole in the front panel
(this hole is in line with the potentiometer shafts).
Coil winding
The last component to mount on the
board is equalising coil L1. It comprises a bobbin and two core halves and
siliconchip.com.au
is wound using 300 turns of 0.25mm
enamelled copper wire.
The coil is wound onto the bobbin
after which the two core halves are fitted, along with a 2.5mm Nylon spacer.
This spacer provides an air gap which
lowers the effective permeability of the
core. This lessens any variations in the
inductance of the equalising core with
respect to temperature.
Winding the coil is straightforward –
it’s simply a matter of winding on the
300 turns of wire and then twisting the
leads together to prevent the coil unwinding. That done, trim these leads
to about 20mm and clean the enamel
from their ends, so that they are ready
to solder to the board.
Important: equalising coil L1 must
be wound so that its self-capacitance
is as low as possible. In practice,
this means that the windings should
be jumble-wound by hand without
regard to neatness. Do not wind each
layer with each turn neatly placed
adjacent to the next.
The core can now be fitted to the
bobbin, as follows. First, insert an M4
x 25mm Nylon screw through one core
half and install three M4 Nylon wash-
ers (these effectively form the 2.5mm
Nylon spacer). That done, install the
second core half in position, fit the
assembly to the PC board and secure it
using an M4 Nylon nut – ie, the screw
protrudes through the PC board and
the nut is placed on the underside.
Finally, solder the two coil leads to
their adjacent PC stakes.
Cut-outs & hardware
If you buy a complete kit, the case
will probably be supplied pre-drilled
and with screen-printed lettering on
the front panel. Alternatively, if you’re
starting from scratch, you will have
to drill the plastic case as shown in
Figs.6-8.
Basically, this involves drilling the
following holes:
• eight holes in the front side of the
case for the pot shafts (7) and the LED;
• holes in the lefthand end and rear
side for the antenna brackets;
• holes in the righthand end for the
two jack plug sockets, the DC power
socket, the two rocker switches and a
banana socket;
• holes in the bottom of the case to attach the metal baseplate and a ¼-inch
August 2006 105
Fig.6: this diagram can be copied and used as a template to mark the hole positions in the ends of the case. Also
shown are the details for the pitch and volume antennas.
Tee nut (which is used to attach the
stand); and
• holes in the lid of the case to mount
the loudspeaker and to let the sound
escape.
Note that the holes for the switches
can be made by first drilling a series
of three holes for each and then filing them to the required rectangular
shape. The banana socket requires
an elongated hole and this can be
done by first drilling and reaming it
to 6mm and then elongating it using
a rat-tail file.
As shown in the photo, the metal
baseplate is attached to the underside
(base) of the case and is secured using M3 x 6mm screws and nuts. The
¼-inch Tee nut goes in the centre
106 Silicon Chip
and is glued to the baseplate and box
using epoxy adhesive. Alternatively,
you could use builders adhesive (eg,
Selleys Liquid Nails).
Note that an eyelet and short length
of green hook-up wire is attached to
the front left corner baseplate mounting screw – see Fig.5
Finally, the lid of the case requires
four 3mm holes to mount the loudspeaker plus a pattern of 13 x 6mm
holes directly in front of the loudspeaker cone.
The antennas
The pitch and volume antennas are
both based on towel-rail end brackets
and lengths of 16mm chromed steel
tubing (or towel railing) – see Fig.6.
The pitch antenna is cut to 375mm
long, while the volume antenna is
125mm long. Plastic end caps are used
to cover the exposed ends of each antenna while the opposite ends fit into
the end brackets which in turn are attached to the case using M4 x 10mm
screws and M4 nuts.
Final assembly
Now we come to the final assembly. The PC board simply clips into
the integral slots inside the case but
before doing this, it’s necessary to first
remove the top screw that’s used to
secure the mounting bracket for the
Volume antenna
In addition, it will be necessary
to remove some of the ribbing inside
siliconchip.com.au
Fig.7: these are the drilling details for the front and rear sides of the case. The 7mm holes can be made by
drilling small pilot holes first and then carefully enlarging them to side using a tapered reamer.
the box adjacent to the DC socket and
around three of the potentiometers,
so that they sit flat against the sides
of the case.
siliconchip.com.au
You can quickly determine what has
to be removed by trial fitting the board
inside the case. A sharp chisel can then
be used to remove the ribbing.
Next, solder the green earth wire
from the groundplane to the GND stake
on the underside of the PC board (ie,
to the same stake that earths the pot
August 2006 107
bodies). A second 150mm-long green
earth wire should then be soldered
to the GND stake on the top of the
PC board for later connection to the
banana socket. Don’t do this after the
PC board is in the case, as heat introduced into the GND stake could melt
the soldered joint for the groundplane
lead without you knowing.
You can now fit the washers to the
pot shafts and insert the PC board into
the box. This is done by angling it so
the pot shafts enter the holes in the
side of the box, after which the board
can be clipped into the integral side
mouldings.
Once it’s in, secure each pot with its
nut and fit the two jack socket nuts.
The leads on the LED can then be bent
down by 90° so that it goes through its
matching hole in the front panel.
All that remains now is to fit the
two switches and the banana socket
and complete the external wiring.
Note that the connections to both
the volume and pitch antenna brackets are made via crimp-connection
eyelets which are secured under the
nuts of the mounting screws. Initially,
the pitch antenna wire should be
connected directly to the PC stake
marked with an “X” (adjacent to
T2), to bypass the equalising coil
(L1). It’s later connected to
its correct PC stake after
the setting-up procedure
has been completed (more
on this later).
The connections to the
two switches can either be soldered or made via spade connectors. The final wiring connections are
to the loudspeaker and to the banana
socket from the GND stake.
Initial checks
Fig.8: here’s how to drill the bottom of the case and the aluminium base
plate. Make sure that the holes for the Tee nut are accurately positioned.
Right: the threaded Tee nut is pushed through
its holes in the baseplate and secured in position
using epoxy adhesive. It accepts the threaded tip
of the microphone desk stand.
108 Silicon Chip
Now for the initial set-up procedure.
Here’s what to do, step-by-step:
Step 1: set trimpots VR9 & VR10 fully
clockwise, VR8 & VR11 fully anticlockwise, VR12 fully anticlockwise
and pots VR1-VR7 to mid-position.
If necessary, now is also a good time
to remove the indicator buttons from
the knobs and replace them so that the
pointers are vertical.
Step 2: check that the power LED
lights when power is applied. If it
doesn’t light, check the polarity of
the DC plug from the plugpack. The
centre pin should be the positive. If
this is correct, then the LED might be
installed the wrong way around.
siliconchip.com.au
The PC board is installed in the case by first angling it down at the front so that the pot shafts pass through their
respective holes in the front panel. The back of the board is then lowered and clipped into the integral slots.
Step 3: check the supply rails to the
ICs. IC2 should have 9V between pins
4 & 11, IC3 should have 9V between
pins 4 & 7, IC4 should have 9V between
pins 4 & 6, and IC5 should have 9V
between pins 4 & 8.
Step 4: connect a multimeter between
test points TP3 and TP GND. Apply
power and adjust transformer T4 for
a reading of about 1.5V.
Step 5: connect the multimeter to TP4
and adjust VR14 for a reading of about
7V, regardless of hand movement near
the volume antenna.
siliconchip.com.au
Step 6: check each oscillator for correct operation by measuring the DC
voltages on the drains of JFETs Q1, Q3
and Q5. These should each measure
between 3V and 6V.
Step 7: check the voltages on the remaining JFETs and transistors. Q2 and
Q4 should have around 0.3-0.4V on
their source (middle) pins; Q6 should
have about 1.4V on its base (middle
pin); and Q7 should have about 7V
on its emitter.
Step 8: vary VR3 and check that the
voltage at TP1 ranges from about 0.7V
to 7V. Similarly, varying VR4 should
vary the voltage on TP2 over the same
range.
Step 9: set VR2 to its centre position
and adjust the slug in T2 until a lowfrequency sound is produced from the
loudspeaker. Check that the pitch of
this sound changes in response to hand
movement near the pitch antenna. This
should start off at a very low frequency
with the hand away from the antenna
and rise in frequency as the hand is
brought nearer to the antenna.
Step 10: attach the microphone desk
August 2006 109
increases as the hand is brought closer
to the pitch antenna.
Frequency changes with hand
movement should now be quite linear
for each octave up to 2048Hz. Note that
if the antenna gives very strange results
or the frequency does not appear to
change, the resonance setting for the
equalising coil is probably incorrect.
In that case, adjust T2’s slug slightly
anticlockwise and readjust T1 until
the effect disappears.
Volume adjustment
The microphone desk stand screws into the Tee
nut that’s attached to the underside of the case.
stand to the unit and readjust transformer T2 carefully until the results
are correct. Check that VR2 alters the
tuning frequency.
Equalising coil
If this is all working, it is time to
tune the unit with the equalising coil
connected. Here’s the step-by-step
procedure:
Step 1: set pot VR2 (Pitch Range) to
its mid-position.
Step 2: wire up the test circuit as
shown in Fig.9 using insulated wire.
Note that the equalising coil lead must
be lifted from point X and connected
to the far left side of the board via a
length of hook-up wire instead. Note
also that the pitch antenna lead is
moved to its correct location.
Step 3: turn T2 slowly and find the
point where the voltage is lowest. In
the prototype, the voltage dropped
from over 2V down to around 0.4V at
the dip. The idea of this test is to find
the frequency where the antenna and
equalising coil resonate, as indicated
by a dip in voltage as T2 is adjusted.
Step 4: move your hand so that it is
about 10cm away from the antenna.
The voltage dip should change by
about 50mV. By contrast, if you incorrectly set T2 at a position away from
the dip setting, the measured voltage
will vary by more than 200mV on
this test.
Step 5: verify this dip in voltage by
placing the lid on the box (as this affects
the reading) and placing your hand
about 10cm away from the antenna.
110 Silicon Chip
Now remove the lid, adjust T2 slightly,
replace the lid and repeat the previous
step (Step 4). Note: the Theremin must
be away from metal objects or the
results will be affected.
Step 6: repeat step 5 several more
times, adjusting T2 just a little each
time (don’t forget to replace the lid
after each adjustment).
If the slug inside T2 has to be set at
the top or bottom of its range to give
the required voltage dip, you will
need to change the number of turns
on L1. Add a turn or two if the slug
is at the top of its range and take off a
turn or two if the slug is at the bottom
of its range. If you cannot find the dip,
check that the antenna has the same
length and diameter as used in our
prototype.
The gap between L1’s cores also
affects the resonance. A slightly
smaller gap will give a lower resonant
frequency and a wider gap will raise
the resonant frequency.
When you are satisfied that the
resonance adjustment is correct, do
not make any further adjustments to
T2’s setting.
Step 7: connect the equalising coil
back into circuit by reconnecting it
to point X, as shown on the overlay
diagram (Fig.5). The two insulated
wiring leads (shown green and orange on Fig.9) should also now be
removed.
Step 8: adjust T1 until the tone is
at a low frequency, then put lid on.
In necessary, readjust T1 so the tone
starts off at very low frequency and
One problem that you may have at
this stage is heterodyning (ie, an audible squeal) in the audio output. This effect is an audible beat frequency which
is produced by frequency differences
between the volume oscillator and the
pitch and reference oscillators.
The solution to this problem is to
adjust transformer T3 until the whistle
disappears. Note that changing T3 may
affect the voltage at TP4. If this drops
below 6V, you may not hear anything
at all and so T4 will need readjusting
to bring TP4’s voltage back above 7V.
Check again for spurious noises in
the sound.
Now connect your multimeter between TP3 and TP GND and adjust
T4 so that voltage falls as your hand
approaches the volume antenna.
Set T4 so that the voltage on TP3 is
around 1.6V.
Note that if you set T4 so TP3 is at
1.3V instead, then the volume control range with hand movement will
be less. This will cause the volume
control to be more abrupt. Conversely,
setting it at more than 1.6V will widen
the control range with hand movement, so there will be more gradual
volume control.
Next, make sure that VR1 is set to
its mid position, then set VR14 so that
TP4 is at 6V when your hand is away
from the volume antenna. That done,
adjust VR1 so that the volume control
range is nice and smooth.
Waveform adjustments
The waveform adjustment range is
made by first setting VR3 fully anticlockwise and adjusting VR9 so that
the reading at TP1 is 0.7V. Once that’s
been done, set VR3 fully clockwise and
adjust VR8 for 1.5V at TP1.
The Symmetry range adjustment
uses a similar procedure. First, set
VR4 fully anticlockwise and adjust
VR11 for 6.9V on TP2, then set VR4
siliconchip.com.au
Fig.9: this diagram shows how to wire the unit for the resonance adjustments (see text). Don’t forget to restore the
equalising coil wiring as shown in Fig.5 and remove the insulated leads after making these adjustments.
fully clockwise and adjust VR10 for
0.9V on TP2. You can experiment with
these ranges but be aware that with
wider adjustment settings, the signal
can drop out for particular settings of
VR3 and VR4.
Skew range
The skew range is adjusted using
VR12. This increasingly limits the
skew range as it is turned clockwise
and vice versa.
You may wish to limit the skew
range for several reasons. First, you
will find that with too much skew control, the lowest frequency that can be
played will be too high. This is because
the pitch and reference oscillators lock
together at high skew settings. The
oscillators will only snap to a different
frequency when pulled sufficiently
by a large change in hand movement
adjacent to the pitch antenna.
Second, once a certain skew level is
reached, further increasing the skew
does not necessarily change the tone.
Finally, too much skew will pull the
reference and pitch oscillators so far
off frequency that the pitch adjustment
siliconchip.com.au
This view shows the
parts on the righthand end of the case.
control will no longer be able to set the
lowest frequency required.
Adjustment of VR12 should be done
with these points in mind.
Earthing
Finally, note that the Theremin
will work best if the circuit earth
connects to either mains earth or to
your body.
A mains earth connection is automatically made if the Theremin
is connected to an earthed amplifier. However, if the Theremin is not
earthed in this way, an earth strap can
be used to connect between your lefthand wrist and the banana socket on
the Theremin. A suitable (anti-static)
strap is available from Jaycar – Cat.
TH-1780.
Alternatively, you could also run
the Theremin from a 12V supply that
has an option to connect the 0V rail
SC
to mains earth.
August 2006 111
Vintage Radio
By RODNEY CHAMPNESS, VK3UG
The HMV B11A 5-valve
battery-operated mantel receiver
Manufactured around 1950, the HMV B11A
is a battery-operated mantel receiver that
was designed for use in rural areas. It was
one of the first domestic receivers to use
miniature 7-pin valves.
B
ATTERY-OPERATED RECEIVERS
made between the mid-1930s and
the late 1940s used valves that required
2V on their filaments and a high-tension (HT) supply of about 135V. This
involved using a 2V lead-acid cell and
three 45V dry batteries.
These batteries were all quite expensive in one way or another. The
2V cell required regular recharging
and this was usually done by the local
radio serviceman or at a local motor
vehicle repair garage. This was not only
inconvenient but also meant that the
household was sometimes deprived of
the use of the radio for a day or two. The
45V batteries could not be recharged
and were expensive to buy.
As a result, battery-operated sets
were usually only turned on when a
specific program was being broadcast,
then turned off. They were certainly
not left on all day as background entertainment, because the cost of running
them was too great. Of course, these
sets were mostly located in rural areas
that lacked mains power, so the batteries had to be conserved as much as
possible.
To lessen the cost of recharging
and replacing batteries, valves were
developed that only required 1.4V
on the filaments and around 90V of
HT. These became available around
the beginning of WWII and used the
octal valve base. Later on, around
1945, 7-pin miniature valves using the
same voltages became available – to
the military at least – and these had
somewhat similar characteristics to
their octal predecessors.
Seven-pin miniature valves were
subsequently used in consumer equipment in the late 1940s and continued
in use up until the early 1960s when
valves gave way to transistors.
The HMV B11A
This is the fully-restored receiver in its cabinet. Automotive cut and polish
can restore old bakelite cabinets to “as-new” condition.
112 Silicon Chip
HMV’s B11A comes in a “chunky”
bakelite case and features a slide-rule
dial scale which was quite typical of
the era. There are only three controls:
off-on-tone, volume and tuning.
The set itself would have been
aimed at the middle of the market. It
is a broadcast band only receiver and
instead of including a radio frequency
(RF) stage as was usual in most 5-valve
battery radios, this set has two stages of
intermediate frequency (IF) amplification instead. This simplified the front
end, as a 2-gang tuning capacitor could
be used instead of a 3-gang unit. This
siliconchip.com.au
also meant that the associated extra
tuning coil and adjustments were not
needed.
One drawback is that the dial scale
has no provision for dial lighting, so
tuning at night requires adequate external lighting. This no doubt was an
economy measure.
The chassis itself was originally
designed to take octal battery valves,
as evidenced by the small plates used
to cover the holes where these valves
were located. The 7-pin miniature
valves use the same locations and so
their sockets are mounted in the middle of these plates.
Circuit details
Fig.1 shows the circuit details of the
set. It’s a fairly conventional superhet
design with no surprises.
The converter is based on a 1R5
which is neutralised via capacitor
C5, with resistor R3 used to smooth
out variations in the oscillator’s output across the band. The 457.5kHz
converter output is then coupled to
the first IF stage which uses a 1T4. Its
output in turn goes to the second IF
stage which also uses a 1T4.
From there, the signal goes to the
detector and an automatic gain control
(AGC) diode in the 1S5. The resulting
audio output from the detector/AGC
diode is then applied to the grid of the
pentode section of the 1S5 via the volume control. This in turn feeds the 3V4
output stage which drives the speaker
via output transformer T1.
The AGC signal is taken from the
top of the volume control and is fed
via R7 to R1, C3 & C11. The receiver
uses simple AGC, as delayed AGC
(DAGC) could not easily be achieved
with the miniature battery valves that
were available. However, this appears
to have little effect on the receiver’s
performance.
The audio amplifier has two negative feedback loops. First, C25 gives
some negative feedback to the screen of
the 1S5 from the voice coil. The other
loop is via C23 when it is connected to
the plate of the 3V4. This capacitor can
be switched to one of three positions
and acts as a tone control.
The 3V4 is the only valve which has
bias applied to it and this is achieved
using back bias resistor R14. The 1S5
obtains contact potential bias due to
the high value of its grid resistor. By
contrast, the RF stages have no standing bias.
siliconchip.com.au
Despite its rather grubby condition, this set was relatively easy to restore
as all the original parts were still in place. The chassis was cleaned by first
dusting it with a paintbrush and then using a kerosene-soaked rag and a
kitchen scourer.
This view shows the front of the chassis after restoration. The dial-drum is
driven by a rubber tyre assembly.
Note that V1 and V2 have AGC
applied to them even with no signal
being received. That’s due to the noise
picked up on the antenna generating
some AGC voltage. V3 has no AGC
applied to it but will develop grid
leak bias if the incoming signal is sufficiently great.
One interesting little circuit quirk is
the fitting of the radio frequency choke
(RFC) CK1 in the filament supply line.
This isolates the second IF amplifier
from the converter and the first IF
amplifier and makes the receiver more
stable. As an experiment, I shorted
out this RFC but found no evidence
of any feedback anywhere across the
broadcast band. Apparently, HMV
wanted to make sure that there was
no likelihood of instability in the IF
amplifier stages.
Dismantling & cleaning
The radio was quite grubby when
August 2006 113
This is the under-chassis view after restoration. The new components are hardly noticeable and this helps to keep
the set looking original.
The chassis is fitted with a roll-over frame and can be tipped
into any position for servicing without damaging other parts.
114 Silicon Chip
it came into my possession, having
been stored for quite a few years after
a nasty accident (more on that later).
The back panel was held on by only
one screw and this was removed, as
were the three knobs at the front.
That done, the two chassis retaining
screws were removed and the chassis
separated from the cabinet.
The first thing I noticed was that the
roll-over frame had four screws missing along the rear of the chassis. This
problem was immediately fixed using
some small self-tapping screws, after
which the chassis was dusted using a
paintbrush to remove any loose dirt. It
was then rubbed down using kerosene
and a kitchen scourer and a most of
the muck came straight off.
Admittedly, there was some
corrosion where mice had been.
Fortunately, their stay must
have been brief, as little damage was caused.
Having removed the grime,
I oiled all the pulleys and
bearings on the dial drive system,
along with the various control shafts.
That done, the dial-drive pointer guide
was cleaned with a kerosene dipped
rag and then oiled sparingly.
siliconchip.com.au
Fig.1: the circuit is a fairly conventional superhet
design based on five miniature 7-pin valves: a 1R5
converter stage, two 1T4 IF stages, a 1S5 detector/
AVC/audio amplifier stage and a 3V4 audio output
stage.
The mechanics of the receiver were
now working as they should, with
one exception: the dial drive was a little “lumpy” in its action due to a flat
spot on the drive rubber. It wasn’t bad
enough to worry about, however.
Next, the speaker grill was removed
(it’s attached to the main part of the
cabinet by four speed nuts), after
which the cabinet (which splits into
two halves) and knobs were given a
good scrub in soapy water. Once dry,
these parts were then polished using
automotive cut and polish and this
brought the cabinet up to as-new appearance.
Overhauling the electronics
With the cleaning done, it was then
time to look at getting the receiver up
and running. Inspection under the
chassis showed an uncluttered layout,
so overhauling the electronics was
relatively easy. In fact, it would be nice
if all receivers were as easy to service
as this one.
The four battery leads had seen better days, so I decided to replace them
with new hook-up wire. There were
no plugs on the battery leads so the
circuit had to be carefully checked
to determine where each wire went
siliconchip.com.au
– connecting the filaments to the HT
lines would not have been nice!
Having done that, I checked for a circuit between the filament positive rail
and chassis. It should have measured
just a few ohms but it was open circuit.
It didn’t take long for the penny to drop
– the previous owner had obviously
connected the 90V HT line to the filaments and in a few milliseconds had
blown the filaments in all five valves.
As a result, I labelled the LT and HT
leads appropriately to avoid making
the same mistake in the future.
Because of the previous owner’s
carelessness, I had to replace all five
valves. Of course, this was also the
likely reason that the radio had been
set aside in the first place.
Fortunately, I have a good stock
of new and secondhand valves, otherwise replacing them would have
been an expensive exercise. In fact,
two of mine were faulty as well, so I
replaced seven valves in all to get the
set operating. These battery valves
have filaments that are rated at 50mA
and are quite delicate. Even when all
operating conditions are optimum,
they have a shorter lives than their
beefier mains-operated cousins.
Before replacing the valves, I
cleaned the sockets with Inox contact cleaner. I then connected my dry
battery eliminator which supplies a
variety of voltages to suit receivers like
this one. The various connections were
then triple-checked before applying
power, to avoid wrecking the valve
filaments again.
With the fresh valves fitted and an
outside antenna and earth attached,
the receiver was up and running but
its performance was poor. Most mains
This close-up view shows the rubber
tyre dial-drive system used on the
B11A receiver.
August 2006 115
This is the old B11A receiver before restoration. It was covered in dust and
grime, having been stored in a garage for many years.
receivers don’t require a separate earth
to achieve good performance as they
are “earthed” capacitively via the
mains. By contrast, a dry-battery set
does not have this “capacitive” earth
and therefore requires an earth for best
performance.
A few quick checks revealed that
the set was drawing normal current
and the voltage readings on all valves
were within specification with one
exception – the voltage on the screen
of the second IF valve was noticeably
higher than it should have been. This
valve didn’t appear to be drawing any
current, so another 1T4 was fitted and
then the set didn’t work at all! The
reason wasn’t hard to find – its filament
was open circuit.
Fortunately, I had another 1T4 and
fitting that made all the difference to
the performance. The set was now
performing quite well, although the
front-end alignment was out, with
stations not quite where they should
appear on the dial.
Alignment
The alignment procedure for this set
is quite straightforward. My first step
was to set the receiver to the 621kHz
mark on the dial, which is marked as
station 3AR (now 3RN). That done, the
oscillator coil slug was adjusted until
3RN came in.
116 Silicon Chip
Next, I tuned to the position for 3AK
(1500kHz) at the other end of the dial
and set my signal generator to run at
1500kHz with tone modulation. The
generator’s output was loosely coupled
to the aerial lead (ie, placed near it) and
I then adjusted the oscillator trimmer
on the tuning gang until I heard the
tone from the speaker.
That done, I rechecked the oscillator
coil adjustment at the low-frequency
end and then at the high-frequency
end again, as these two adjustments
interact with each other. I then tuned
to a nearby relatively weak station at
the high-frequency end of the dial and
peaked the antenna trimmer.
Having completed the front-end
alignment, it was time to align the
IF stages. This should also be done
with the set tuned to a weak station.
However, I found that the IF transformers were all correctly aligned, so no
work was required here. This didn’t
surprise me, as the set appears to have
had very little work done on it under
the chassis.
Finally, the various adjustments
were all sealed using a dab of nail
polish on the trimmers and re-melted
wax (using a soldering iron) on the
adjustment slugs.
Capacitor checks
Some readers may be wondering
why my standard practice of checking
all critical capacitors before switching
on was skipped on this occasion. The
reason is that because the voltages are
relatively low in this battery-operated
set, a few liberties were taken.
However, once the set was working,
I decided to take a closer look. Normally, I would replace audio coupler
C24 and the two AGC bypass capacitors (C3 & C11). In this set, however,
the audio coupler is a mica capacitor
and had minimal leakage, so it wasn’t
worth replacing. And if the two AGC
bypasses have high leakage, it won’t
harm the set – it just won’t work as
well and will probably overload on
strong signals.
I checked the voltage on the grid
of the 3V4 with a digital multimeter
and it was normal. I then tuned the
set to a strong station and measured
-5V at the detector and only -2.5V on
the AGC line. As a result, I replaced
the two AGC bypasses and the voltage
on the detector dropped to -3.5V (the
voltage across the two AGC bypasses
was also -3.5V). The AGC system was
now working as it should and the audio output level was nearly the same
on both strong and weak stations.
Next, I checked the paper capacitors
on the HT line and replaced any that
had excessive leakage (as measured
on my high-voltage insulation tester).
I also checked the HT filter electrolytic
capacitor (C22) and found that it had
dropped to just 1mF. This was replaced
with a 22mF 160V electrolytic, as I
didn’t have the correct value (8mF).
The receiver was now performing
quite well and proved to be remarkably
quiet with no signal coming in. It will
operate quite successfully with the HT
voltage as low as 45V. We often look at
such simple sets and think that they
cannot be good performers. However,
as shown by this set, that assumption
is often wrong.
Summary
The HMV B11A really is a surprise
packet. It’s a rather unassuming little
set but gives a very good account of
itself. It is quite sensitive, has adequate
volume and will work satisfactorily
with nearly exhausted dry batteries.
The design is straightforward and access for servicing is good.
HMV receivers of this era have always impressed me and this one is no
exception. It is a worthwhile addition
SC
to any radio buff’s collection.
siliconchip.com.au
Salvage It!
BY JULIAN EDGAR
The good bits inside flatbed scanners!
It’s not hard to obtain a computer flatbed
scanner for nothing – they’re a frequent
discard that can be found at garage sales,
kerbside rubbish collections and the tip. But
what use can be made of the parts inside?
Despite first appearances, quite a lot.
Pulling a scanner apart is easy: most
models just clip together and can be
separated by the judicious use of a
screwdriver. Inside you’ll find a moving carriage on which the cold cathode
fluorescent lamp (CCFL), focusing lens
and charge coupled device (CCD) image
sensor are mounted. In addition, the
carriage contains two or three mirrors
to reflect the image to the lens.
The carriage is driven by a geareddown stepper motor that operates a
toothed belt. There’s usually also a
position sensor to detect when the
carriage is in its “start” position and,
of course, the necessary image processing circuitry.
So getting the bits is easy – but what
can you do with them?
The CCFL
The Cold Cathode Fluorescent
Light (CCFL) is run by a high voltage
(HV) power supply which produces
several hundred volts. Warning – it’s
high enough to give you a nasty shock
Many scanners use small stepper motors integrated into a reduction gear train.
These make excellent hand-cranked generators (complete with a ~1:16 step-up
ratio) or they can be used conventionally in a host of projects.
siliconchip.com.au
or burn your skin! In fact, given the
right circumstances, a shock could
be fatal.
Salvaging this part of the system is
very easy – in most scanners, the HV
power supply is mounted close to the
CCFL on the carriage or alternatively,
is mounted remotely and is connected
to the CCFL via some HV wires. The
HV power supply is a separate circuit
board and contains a transformer,
inductor, a few capacitors and some
transistors.
The power supply is fed by either
two or three wires. When there is a
pair, you’ll normally find that they are
red and black – red for positive, black
for negative. Observing the polarity,
connect a variable voltage power supply to these wires and slowly wind
up the voltage. The CCFL will first
light at anywhere from 4.5–21V but
note that the HV power supply itself
delivers several hundred volts to the
lamp. If the original input voltage is
unknown, don’t go up any more than
a few volts over the “light-up” voltage
of the CCFL.
A 3-wire power supply also includes
a “control” input (in addition to the red
and black wires). If power is applied
via the red and black wires, supplying
this control input with a small voltage
(eg, 1V) will cause the CCFL to light.
CCFLs have some major advantages
over other lighting sources. First, the
tubes are extremely thin – 2.5mm is
common. Second, they provide a diffuse light, usually with good colour
rendition. And third, they are quite
bright but at the same time remain
cool!
However, you must remember that
the tubes are also fragile – where
possible, they should be supported
in exactly the same way as they were
in the scanner carriage. Remember
also that the power supply should be
housed in a plastic case and the lamp
August 2006 117
All flatbed scanners contain a
Cold Cathode Fluorescent Light
(CCFL) and its accompanying
high-voltage power supply. It’s
very easy to make these work
separately from the scanner, to
provide a free (or very low-cost)
2-3W fluorescent tube that can
be powered by low-voltage DC!
connections must be well insulated
and away from probing fingers.
Scanner CCFLs are typically rated
at 2-3W and are ideal for use in model
railway layouts (where they can provide concealed factory and station
lighting), for low voltage lighting (eg,
in a caravan or solar home) and for
instrument and gauge lighting.
Front Housing
The front of the scanner consists
of a flat sheet of high-quality glass
mounted in a plastic housing. And
that’s it – most times, the electronics,
carriage and motor are all in the bottom
half of the scanner. So what use is this
top half? Well, it isn’t an electronic application but if the housing is placed
over a shallow tray that’s been filled
with soil, you get an ideal device for
germinating seeds.
Want some other uses? The front
housing can also be used to protect
solar cells that aren’t already under
glass, or you can make a picture frame
that matches the glass size. When I was
a kid, I made a solar pie warmer that
used a front glass sheet very similar in
size to a typical flat bed scanner’s glass
panel – so there’s another use.
In short, wherever you need a precut, zero cost small sheet of good
quality glass, here it is! Why on earth
would you throw it away?
Stepper Motor
Scanners use stepper motors that are
attached to compact reduction gears.
Unlike many discarded consumer
goods from which you can obtain
steppers, the scanner stepper and its
gear train often comprise a standalone,
easily removable assembly. So if you
want a small stepper (they’re typically
25–35mm in diameter) that’s integrated with a ~16:1 reduction drive and
forms an assembly that’s only about
Rat It Before You Chuck It!
Whenever you throw away an old TV (or
VCR or washing machine or dishwasher
or printer) do you always think that surely
there must be some good salvageable
components inside? Well, this column is
for you! (And it’s also for people without a
lot of dough.) Each month we’ll use bits
and pieces sourced from discards, sometimes in mini-projects and other times as
an ideas smorgasbord.
And you can contribute as well. If you
have a use for specific parts which can
118 Silicon Chip
easily be salvaged from goods commonly
being thrown away, we’d love to hear from
you. Perhaps you use the pressure switch
from a washing machine to control a pump.
Or maybe you have a use for the highquality bearings from VCR heads. Or
perhaps you’ve found how the guts of a
cassette player can be easily turned into
a metal detector. (Well, we made the last
one up but you get the idea . . .)
If you have some practical ideas, write
in and tell us!
70 x 50 x 40mm, reach for the nearest
discarded scanner.
To drive these motors, you’ll need
a stepper motor control circuit. Of
course, the scanner already incorporated this but it’s easiest to use new
circuitry to achieve the control you
want – eg, the Stepper Motor Controller kit described in the May 2002 issue
of SILICON CHIP.
Alternatively, you can apply physical effort to rotate the output shaft
and so generate power! The 16:1
reduction ratio then becomes a 1:16
step-up ratio.
By adding a crank handle to the output cog (this is easy because this cog
originally needed clearance to drive
the belt and so always stands proud),
you can take advantage of the gear train
to turn the stepper motor at an easilyachievable 1500 RPM! The resulting
power produced is enough to charge a
battery or run a white LED.
For more on using stepper motors as
alternators, see “Our Fantastic HumanPowered LED Torches” in the February
2004 issue of SILICON CHIP.
The benefit of taking this approach
over using a larger, direct-driven stepper is that a very compact generator or
hand-cranked torch can be built. The
disadvantage is that the plastic gear
train may have a short life.
Miscellaneous
Don’t forget the other bits and pieces
inside the scanner. I always salvage the
chrome-plated steel bar on which the
carriage rides (and it runs in bronze
bushes, no less!). These bars are typisiliconchip.com.au
contain a variety of pre-focusing lenses
– and curved mirrors – but it’s the lens
closest to the image sensor that’s the
“good ‘un”. Often only about 8mm dia
meter by 10mm long, these typically
have a focal length of just of 15mm and
make for extremely effective close-up
hand lenses. They’re not super bright
but they’re of excellent quality and
provide huge magnification. They’re
just the thing for inspecting solder
joints or checking just how dull the
ends of those supposedly sharp multimeter probes are!
Finally, most scanners are powered
by plugpacks and many people throw
these away at the same time as they’re
getting rid of the scanner. It’s worth
keeping – you can never have too many
different plugpacks on the shelf.
Conclusion
Here’s a use out of left field. A scanner cover makes the ideal top half for a
small seed germinator. Alternatively, the glass can be used to cover solar cells,
in small solar projects or even in a picture frame!
cally 8mm in diameter and if you have
a metal turning lathe and/or a set of
thread-cutting dies, are excellent raw
material for all sorts of projects.
You’ll also find front-faced mirrors
(that is, the reflected light doesn’t have
to pass through the glass) and Halleffect position sensors.
I’ve nearly forgotten one of the gems
– the final focusing lens. Scanners
Not interested in free low-voltage
fluorescent lighting? Or seed germination boxes? Or geared stepper motors? Or hand-cranked generators? Or
a compact, high-magnification hand
lens? Or salvaging another plugpack
without cost?
That’s OK – just be sure you give any
old scanners that you have to someone
SC
who can make use of them!
From the publishers of SILICON
CHIP
PERFORMANCE
ELECTRONICS
FOR CARS
NOT A REPRINT: More than 160 pages of new and
exciting projects never published before – all designed
to get top performance from your car.
FASCINATING ARTICLES: 7 chapters explaining your
car – engine management, car electronics systems, etc
ADVANCED PROJECTS: You’ll build controllers for turbo
boost, nitrous, fuel injection and much more!
We explain the why as well as the how to!
Available direct from the Publisher ($22.50 inc postage):
Silicon Chip Publications, PO Box 139, Collaroy NSW 2097. Ph (02) 9939 3295; Fax (02) 9939 2648;
email silchip<at>siliconchip.com.au or via our website: www.siliconchip.com.au
siliconchip.com.au
August 2006 119
ALL S ILICON C HIP SUBSCRIBERS – PRINT,
OR BOTH – AUTOMATICALLY QUALIFY FOR A
REFERENCE $ave 10%ONLINE
DISCOUNT ON ALL BOOK OR PARTSHOP PURCHASES.
CHIP BOOKSHOP 10% (Does not apply to subscriptions)
SILICON
For the latest titles and information, please refer to our website books page: www.siliconchip.com.au/Shop/Books
PIC MICROCONTROLLERS: know it all
SELF ON AUDIO
Multiple authors $85.00
The best of subjects Newnes authors have written over the past few years,
combined in a one-stop maxi reference. Covers introduction to PICs and their
programming in Assembly, PICBASIC, MBASIC & C. 900+ pages.
PROGRAMMING and CUSTOMIZING THE
PICAXE By David Lincoln (2nd Ed, 2011) $65.00*
A great aid when wrestling with applications for the PICAXE
See
series of microcontrollers, at beginner, intermediate and
Review
April
advanced levels. Every electronics class, school and library should have a
copy, along with anyone who works with PICAXEs. 300 pages in paperback. 2011
PIC IN PRACTICE
by D W Smith. 2nd Edition - published 2006 $60.00*
Based on popular short courses on the PIC, for professionals, students
and teachers. Can be used at a variety of levels. An ideal introduction to the
world of microcontrollers. 255 pages in paperback.
PIC MICROCONTROLLER – your personal introductory course By John Morton 3rd edition 2005. $60.00*
A unique and practical guide to getting up and running with the PIC. It assumes no knowledge of microcontrollers – ideal introduction for students,
teachers, technicians and electronics enthusiasts. Revised 3rd edition focuses entirely
on re-programmable flash PICs such as 16F54, 16F84 12F508 and 12F675. 226 pages
in paperback.
by Douglas Self 2nd Edition 2006 $69.00*
A collection of 35 classic magazine articles offering a dependable methodology for designing audio power amplifiers to improve performance at every
point without significantly increasing cost. Includes compressors/limiters,
hybrid bipolar/FET amps, electronic switching and more. 467 pages in paperback.
SMALL SIGNAL AUDIO DESIGN
By Douglas Self – First Edition 2010 $95.00*
The latest from the Guru of audio. Explains audio concepts in easy-to-understand language with plenty of examples and reasoning. Inspiration for audio
designers, superb background for audio enthusiasts and especially where it comes to
component peculiarities and limitations. Expensive? Yes. Value for money? YES! Highly
recommended. 558 pages in paperback.
AUDIO POWER AMPLIFIER DESIGN HANDBOOK
by Douglas Self – 5th Edition 2009 $85.00*
"The Bible" on audio power amplifiers. Many revisions and
updates to the previous edition and now has an extra three
chapters covering Class XD, Power Amp Input Systems and
Input Processing and Auxiliarly Subsystems. Not cheap and not a book
for the beginner but if you want the best reference on Audio Power Amps,
you want this one! 463 pages in paperback.
DVD PLAYERS AND DRIVES
by K.F. Ibrahim. Published 2003. $71.00*
OP AMPS FOR EVERYONE
By Bruce Carter – 4th Edition 2013 $83.00*
This is the bible for anyone designing op amp circuits and you don't
have to be an engineer to get the most out of it. It is written in simple language
but gives lots of in-depth info, bridging the gap between the theoretical and the
practical. 281 pages,
A guide to DVD technology and applications, with particular focus
on design issues and pitfalls, maintenance and repair. Ideal for
engineers, technicians, students of consumer electronics and
sales and installation staff. 319 pages in paperback.
by Sanjaya Maniktala, Published April 2012. $83.00
Thoroughly revised! The most comprehensive study available of theoretical and practical aspects of controlling and measuring
EMI in switching power supplies.
Subtitled Exploring the PIC32, a Microchip insider tells all on this powerful
PIC! Focuses on examples and exercises that show how to solve common,
real-world design problems quickly. Includes handy checklists. FREE CD-ROM includes
source code in C, the Microchip C30 compiler, and MPLAB SIM. 400 pages paperback.
By Garry Cratt – Latest (7th) Edition 2008 $49.00
Written in Australia, for Australian conditions by one of Australia's foremost
satellite TV experts. If there is anything you wanted to know about setting up
a satellite TV system, (including what you can't do!) it's sure to be covered
in this 176-page paperback book.
See
Review
Feb
2004
SWITCHING POWER SUPPLIES A-Z
PROGRAMMING 32-bit MICROCONTROLLERS
IN C By Luci di Jasio (2008) $79.00*
PRACTICAL GUIDE TO SATELLITE TV
See
Review
March
2010
ELECTRIC MOTORS AND DRIVES
By Austin Hughes & Bill Drury - 4th edition 2013 $59.00*
This is a very easy to read book with very little mathematics or
formulas. It covers the basics of all the main motor types, DC
permanent magnet and wound field, AC induction and steppers and
gives a very good description of how speed control circuits work with these
motors. Soft covers, 444 pages.
NEWNES GUIDE TO TV & VIDEO TECHNOLOGY
By KF Ibrahim 4th Edition (Published 2007) $49.00
It's back! Provides a full and comprehensive coverage of video and television technology including HDTV and DVD. Starts with fundamentals so is
ideal for students but covers in-depth technologies such as Blu-ray, DLP,
Digital TV, etc so is also perfect for engineers. 600+ pages in paperback.
RF CIRCUIT DESIGN
by Chris Bowick, Second Edition, 2008. $63.00*
The classic RF circuit design book. RF circuit design is now more important
that ever in the wireless world. In most of the wireless devices that we use
there is an RF component – this book tells how to design and integrate in a
very practical fashion. 244 pages in paperback.
PRACTICAL RF HANDBOOK
AC MACHINES
By Jim Lowe Published 2006 $66.00*
Applicable to Australian trades-level courses including NE10 AC Machines,
NE12 Synchronous Machines and the AC part of NE30 Electric Motor
Control and Protection. Covering polyphase induction motors, singlephase motors, synchronous machines and polyphase motor starting. 160
pages in paperback.
PRACTICAL VARIABLE SPEED DRIVES &
POWER ELECTRONICS
Se
e
by Malcolm Barnes. 1st Ed, Feb 2003. $73.00* Review
An essential reference for engineers and anyone who wishes
to design or use variable speed drives for induction motors.
286 pages in soft cover.
Feb
2003
BUILD YOUR OWN ELECTRIC MOTORCYCLE
by Carl Vogel. Published 2009. $40.00*
by Ian Hickman. 4th edition 2007 $61.00*
Alternative fuel expert Carl Vogel gives you a hands-on guide with
A guide to RF design for engineers, technicians, students and enthusiasts.
the latest technical information and easy-to-follow instructions
Covers key topics in RF: analog design principles, transmission lines,
for building a two-wheeled electric vehicle – from a streamlined
couplers, transformers, amplifiers, oscillators, modulation, transmitters and
scooter to a full-sized motorcycle. 384 pages in soft cover.
receivers, propagation and antennas. 279 pages in paperback.
*NOTE: ALL PRICES ARE PLUS P&P – AUSTRALIA ONLY: $10.00 per order; NZ – $AU12.00 PER BOOK; REST OF WORLD $AU18.00 PER BOOK
To
Place
Your
Order:
INTERNET (24/7)
PAYPAL (24/7)
eMAIL (24/7)
www.siliconchip.
com.au/Shop/Books
Use your PayPal account
silicon<at>siliconchip.com.au
silicon<at>siliconchip.com.au
with order & credit card details
FAX (24/7)
MAIL (24/7)
Your order and card details to Your order to PO Box 139
Collaroy NSW 2097
(02) 9939 2648 with all details
PHONE – (9-5, Mon-Fri)
Call (02) 9939 3295 with
with order & credit card details
You can also order and pay for books by cheque/money order (Mail Only). Make cheques payable to Silicon Chip Publications.
ALL TITLES SUBJECT TO AVAILABILITY. PRICES VALID FOR MONTH OF MAGAZINE ISSUE ONLY. ALL PRICES INCLUDE GST
ALL S ILICON C HIP SUBSCRIBERS – PRINT,
OR BOTH – AUTOMATICALLY QUALIFY FOR A
REFERENCE $ave 10%ONLINE
DISCOUNT ON ALL BOOK OR PARTSHOP PURCHASES.
CHIP BOOKSHOP 10% (Does not apply to subscriptions)
SILICON
For the latest titles and information, please refer to our website books page: www.siliconchip.com.au/Shop/Books
PIC MICROCONTROLLERS: know it all
SELF ON AUDIO
Multiple authors $85.00
The best of subjects Newnes authors have written over the past few years,
combined in a one-stop maxi reference. Covers introduction to PICs and their
programming in Assembly, PICBASIC, MBASIC & C. 900+ pages.
PROGRAMMING and CUSTOMIZING THE
PICAXE By David Lincoln (2nd Ed, 2011) $65.00*
A great aid when wrestling with applications for the PICAXE
See
series of microcontrollers, at beginner, intermediate and
Review
April
advanced levels. Every electronics class, school and library should have a
copy, along with anyone who works with PICAXEs. 300 pages in paperback. 2011
PIC IN PRACTICE
by D W Smith. 2nd Edition - published 2006 $60.00*
Based on popular short courses on the PIC, for professionals, students
and teachers. Can be used at a variety of levels. An ideal introduction to the
world of microcontrollers. 255 pages in paperback.
PIC MICROCONTROLLER – your personal introductory course By John Morton 3rd edition 2005. $60.00*
A unique and practical guide to getting up and running with the PIC. It assumes no knowledge of microcontrollers – ideal introduction for students,
teachers, technicians and electronics enthusiasts. Revised 3rd edition focuses entirely
on re-programmable flash PICs such as 16F54, 16F84 12F508 and 12F675. 226 pages
in paperback.
by Douglas Self 2nd Edition 2006 $69.00*
A collection of 35 classic magazine articles offering a dependable methodology for designing audio power amplifiers to improve performance at every
point without significantly increasing cost. Includes compressors/limiters,
hybrid bipolar/FET amps, electronic switching and more. 467 pages in paperback.
SMALL SIGNAL AUDIO DESIGN
By Douglas Self – First Edition 2010 $95.00*
The latest from the Guru of audio. Explains audio concepts in easy-to-understand language with plenty of examples and reasoning. Inspiration for audio
designers, superb background for audio enthusiasts and especially where it comes to
component peculiarities and limitations. Expensive? Yes. Value for money? YES! Highly
recommended. 558 pages in paperback.
AUDIO POWER AMPLIFIER DESIGN HANDBOOK
by Douglas Self – 5th Edition 2009 $85.00*
"The Bible" on audio power amplifiers. Many revisions and
updates to the previous edition and now has an extra three
chapters covering Class XD, Power Amp Input Systems and
Input Processing and Auxiliarly Subsystems. Not cheap and not a book
for the beginner but if you want the best reference on Audio Power Amps,
you want this one! 463 pages in paperback.
DVD PLAYERS AND DRIVES
by K.F. Ibrahim. Published 2003. $71.00*
OP AMPS FOR EVERYONE
By Bruce Carter – 4th Edition 2013 $83.00*
This is the bible for anyone designing op amp circuits and you don't
have to be an engineer to get the most out of it. It is written in simple language
but gives lots of in-depth info, bridging the gap between the theoretical and the
practical. 281 pages,
A guide to DVD technology and applications, with particular focus
on design issues and pitfalls, maintenance and repair. Ideal for
engineers, technicians, students of consumer electronics and
sales and installation staff. 319 pages in paperback.
by Sanjaya Maniktala, Published April 2012. $83.00
Thoroughly revised! The most comprehensive study available of theoretical and practical aspects of controlling and measuring
EMI in switching power supplies.
Subtitled Exploring the PIC32, a Microchip insider tells all on this powerful
PIC! Focuses on examples and exercises that show how to solve common,
real-world design problems quickly. Includes handy checklists. FREE CD-ROM includes
source code in C, the Microchip C30 compiler, and MPLAB SIM. 400 pages paperback.
By Garry Cratt – Latest (7th) Edition 2008 $49.00
Written in Australia, for Australian conditions by one of Australia's foremost
satellite TV experts. If there is anything you wanted to know about setting up
a satellite TV system, (including what you can't do!) it's sure to be covered
in this 176-page paperback book.
See
Review
Feb
2004
SWITCHING POWER SUPPLIES A-Z
PROGRAMMING 32-bit MICROCONTROLLERS
IN C By Luci di Jasio (2008) $79.00*
PRACTICAL GUIDE TO SATELLITE TV
See
Review
March
2010
ELECTRIC MOTORS AND DRIVES
By Austin Hughes & Bill Drury - 4th edition 2013 $59.00*
This is a very easy to read book with very little mathematics or
formulas. It covers the basics of all the main motor types, DC
permanent magnet and wound field, AC induction and steppers and
gives a very good description of how speed control circuits work with these
motors. Soft covers, 444 pages.
NEWNES GUIDE TO TV & VIDEO TECHNOLOGY
By KF Ibrahim 4th Edition (Published 2007) $49.00
It's back! Provides a full and comprehensive coverage of video and television technology including HDTV and DVD. Starts with fundamentals so is
ideal for students but covers in-depth technologies such as Blu-ray, DLP,
Digital TV, etc so is also perfect for engineers. 600+ pages in paperback.
RF CIRCUIT DESIGN
by Chris Bowick, Second Edition, 2008. $63.00*
The classic RF circuit design book. RF circuit design is now more important
that ever in the wireless world. In most of the wireless devices that we use
there is an RF component – this book tells how to design and integrate in a
very practical fashion. 244 pages in paperback.
PRACTICAL RF HANDBOOK
AC MACHINES
By Jim Lowe Published 2006 $66.00*
Applicable to Australian trades-level courses including NE10 AC Machines,
NE12 Synchronous Machines and the AC part of NE30 Electric Motor
Control and Protection. Covering polyphase induction motors, singlephase motors, synchronous machines and polyphase motor starting. 160
pages in paperback.
PRACTICAL VARIABLE SPEED DRIVES &
POWER ELECTRONICS
Se
e
by Malcolm Barnes. 1st Ed, Feb 2003. $73.00* Review
An essential reference for engineers and anyone who wishes
to design or use variable speed drives for induction motors.
286 pages in soft cover.
Feb
2003
BUILD YOUR OWN ELECTRIC MOTORCYCLE
by Carl Vogel. Published 2009. $40.00*
by Ian Hickman. 4th edition 2007 $61.00*
Alternative fuel expert Carl Vogel gives you a hands-on guide with
A guide to RF design for engineers, technicians, students and enthusiasts.
the latest technical information and easy-to-follow instructions
Covers key topics in RF: analog design principles, transmission lines,
for building a two-wheeled electric vehicle – from a streamlined
couplers, transformers, amplifiers, oscillators, modulation, transmitters and
scooter to a full-sized motorcycle. 384 pages in soft cover.
receivers, propagation and antennas. 279 pages in paperback.
*NOTE: ALL PRICES ARE PLUS P&P – AUSTRALIA ONLY: $10.00 per order; NZ – $AU12.00 PER BOOK; REST OF WORLD $AU18.00 PER BOOK
To
Place
Your
Order:
INTERNET (24/7)
PAYPAL (24/7)
eMAIL (24/7)
www.siliconchip.
com.au/Shop/Books
Use your PayPal account
silicon<at>siliconchip.com.au
silicon<at>siliconchip.com.au
with order & credit card details
FAX (24/7)
MAIL (24/7)
Your order and card details to Your order to PO Box 139
Collaroy NSW 2097
(02) 9939 2648 with all details
PHONE – (9-5, Mon-Fri)
Call (02) 9939 3295 with
with order & credit card details
You can also order and pay for books by cheque/money order (Mail Only). Make cheques payable to Silicon Chip Publications.
ALL TITLES SUBJECT TO AVAILABILITY. PRICES VALID FOR MONTH OF MAGAZINE ISSUE ONLY. ALL PRICES INCLUDE GST
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. Write to: Ask Silicon Chip, PO Box 139, Collaroy Beach, NSW 2097; or
send an email to silchip<at>siliconchip.com.au
TV signal
transfer problem
Are you aware of a device that can
transmit TV RF signals room to room
without coax cables or a VCR; ie, incoming RF from aerial to remote TV,
not using A/V transmitters? I have an
application where it would make life
a lot easier. Perhaps you could advise?
(I. M., via email).
• One possible approach may be to
adapt the portable masthead antenna
described in the August 1996 issue.
It will handle UHF and VHF signals.
You would need to connect its output
to a dipole antenna.
connect it to my PC logging multimeter
and want to know which pin I can get
an analog voltage equivalent to EMF
reading? (G. J., via email).
• There is no convenient place to connect a data logger since the DC signal
is a high impedance that is suitable for
the ICL7106 but not a data logger.
To enable a Data logger connection,
you would need to add a 10kW resistor
to the cathode side of diode D1 (this
diode connects to the pin 6 output of
IC2, an OP77). Then connect a 10mF
capacitor to the end of this resistor to
ground (plus side to the resistor). The
data logger can connect to the capacitor terminals.
Data logger connection
for magnetic field meter
Light dimmer has
reduced brightness
A few years ago I bought a Magnetic
Field Meter, as featured in the October
1991 issue. It has an LCD panel meter
and a 3-way rotary range switch and
runs from a 9V battery. I now want to
I recently assembled one of your
projects titled “Touch/Infrared Light
Dimmer” back in January & February
2002. It passed the low-voltage test
using the small bulb as suggested in
10-Level Tank Gauge Wanted
I recently wanted a water tank
gauge and searched high and low for
an economical commercial unit. My
search unearthed the “Water Level
Indicator” in the April 2002 issue of
SILICON CHIP. Its only shortcoming
was the 20% increment spacing. In
my tank’s case, this represents about
7400 litres and I would prefer more
accurate readings.
It was noted that the LM3914 had
10 comparator outputs and I toyed
with the idea of obtaining this kit
and modifying it to accommodate
10 LEDs. However, I recognised the
“Multi-Voltage Monitor” in the May
2006 issue as a similar project and
I think I have my answer.
If I construct this monitor, is there
any reason why I couldn’t add the
power supply, the “critical level”
indication (if required) and a sensor
122 Silicon Chip
array to convert this kit to the level
indicator I desire? I see my main
hurdle as the component selection
for the sensors, where I now will
have 11 sensor inputs as opposed to
the original six. How do I calculate
the resistor values please?
As well as providing me with this
answer perhaps you will consider a
“Mark II” version of the Tank Level
Indicator as I’m sure there are a lot
of punters out there that would
appreciate this luxury, especially
now that there has been a droughtinduced tank population explosion
in Australia. (P. W., via email).
• The calculations for the resistors
are quite tedious, particularly for 11
values. An easier method is to start
out with trimpots and adjust these
so the LEDs show correctly for each
tank level.
the article. And yes, I did change the
.001mF capacitor back to 0.1mF but
once I installed it, the unit can only
reach ~25% brightness level.
I suspect maybe the phase is too late,
as shown on one of the scope shots
published in the January issue. What
should I do to troubleshoot this?
By the way, I changed the 4MHz
PIC16F84 to a 10MHz device and reprogrammed it with the hex file from
your site. Did I miss something here?
(H. H., via email).
• The correct phase control is dependent on the correct detection of
the mains waveform zero crossing.
So the 680kW resistors and the 10nF
(.01mF) capacitor at pin 6 of IC1 must
be correct. Check them out.
The 10MHz version of the PIC
should be used and in fact is what
we specified in the parts list. Use either the 10MHz or 20MHz versions.
A 4MHz PIC cannot be used as we
are running the PIC at 10MHz using
crystal X1.
Curious non-linearity
in amplifier module
I recently built two audio amplifiers using Altronics kits but replaced
the LM3876T with a LM3886TF and
dropped the rails to ±28V as suggested
by you for a 4-ohm load.
Both outputs are linear up to about
±9.5V peak-to-peak on sinewave but
at this point the tops of the sinewaves
clip. With increased drive, the bottoms
of the sinewaves clip at about -22V
which, for a symmetrical waveform,
would correspond to 60 watts output.
The linear gain was measured at 19 as
expected.
Have you any idea what may be
wrong? Presumably, something must
have happened to each LM3886. (R.
E., via email).
• This is an interesting problem
which could cause anyone to tear their
hair out. The likely cause is that you
do not have both the supply pins (1 &
5) properly connected to the +28V rail.
siliconchip.com.au
Queries On 3-Phase Motor Controller
Our electric cooperative serves a
large sewer-lift station that utilises
a solid state GE soft start on a 300
HP 3-phase 480V motor. We supply
the station from a 480/277V transformer. They began experiencing
problems while starting the motor
from day one. I used a Metrosonics
PA-9 PQ Analyser to capture the
motor start sequence, including
voltage and current waveforms both
at the transformer and at the output
of the soft starter.
This particular soft starter achiev
es a reduced voltage level for motor starting by utilising solid-state
switching devices to turn the voltage applied to the motor off and
back on at various points along the
voltage waveform. After looking
at the voltage waveforms coming
from the soft starter (measuring
Modifying the
SLA float charger
I have purchased several 12V SLA
float chargers as described in the
March 2003 issue. Rather than use
an AC supply, I would like to be able
to use a DC supply, as I have a large
regulated supply that will at the same
time be powering Nicad/NiMH battery
chargers.
What would be the best way of
modifying the circuit? Can I complete
the kit as normal and just feed the
DC in on the correct rails or omit the
rectifier part of the circuit? (G. I., via
email).
• You can build the circuit as it is
shown and power the charger from DC.
The supply voltage needs to be at least
15V. Alternatively remove diodes D4,
D6, D7 & D8 and place a link in the D6
position. You can then use a minimum
of 14.5V DC for the input supply.
Bigger transformer
for preamplifier
I’m completing my third pair of
SC480 50W amplifier modules. They
will mate up with the Studio Series
Preamplifier and the Studio Series
Remote Control. I have a toroidal
transformer on hand that I would like
to put into service for the power supply
siliconchip.com.au
the phase-to-ground potential), I
noticed that the waveform showed
the voltage dropping below the zero
level during the “off” time for both
the positive half cycle and negative
half cycle.
Keeping in mind that the motor
was connected in a delta configuration (phase-to-phase) to the soft
starter and my measurements were
phase-to-ground, do those zero
crossings really mean anything? I
have heard that a solid-state switching device exhibiting zero crossings
on the output when connected to a
sinusoidal source is a good indication that it is bad. Any information
you can supply would be greatly
appreciated. R. C., via email).
• We are not at all familiar with
the system you describe but we can
make a number of comments. First,
but it is 18V + 18V (at 50VA) and not
15V + 15V as specified.
Although the difference seems
slight, would it cause any problems,
such as overheating regulators? (J. H.,
Falmouth, Tas).
• Unfortunately, an 18V transformer
is unsuitable for two reasons. First,
the higher voltage will indeed cause
excessive power dissipation in the
voltage regulators, particularly when
the headphone amplifier is installed.
In addition, the rectified output voltage will exceed the voltage rating of the
2200mF 25V filter capacitors. Higher
voltage (35V) capacitors will fix this
problem but there may be problems
fitting some physically larger variants
on the board.
Problem with
telephone dialler
I have a problem with the Telephone
Dialler (April 2003) which I cannot
figure out. When setting up and testing, it works fine and dials my mobile
perfectly. However when I disconnect
the dialler from my PC and turn off
power and then hook up to modem and
turn power on again, the LED flashes
slowly (trying to get communication
with Modem). It doesn’t matter what
I do, I cannot get the dialler to go into
scan mode (LED flashing faster).
if the controller only varies the voltage and not the frequency to achieve
soft starting then the only way it can
do it is by phase-controlled switching, probably using Triacs or SCRs.
Second, while Triacs or SCRs turn
off when the current reduces to zero
or goes slightly negative, the voltage
can still swing quite a lot negative as
the motor is commutated off.
If the commutation from cycle
to cycle is erratic, it could mean
that the snubber networks across
the SCRs/Triacs are not correct for
the load.
Of course, if the controller varies
the frequency as well as the voltage,
then none of the above applies because the electronics will use IGBTs.
In any case, it sounds as though you
need an experienced technician to
check it out.
To get the dialler to work, I have to
disconnect the modem and hook up
dialler back to the PC again. I then
type (0) to simulate that the dialler
has found the modem. Then WITHOUT disconnecting power to dialler,
I just pull out serial cable plug it into
modem then it works fine UNTIL you
turn the power off which leads me
back to square one. Why is it doing
this every time I turn the phone dialler
off? My guess was the configuration of
modem but all the commands in article
work fine. The modem understands
everything.
My Modem is a Dynalink 1456VQE.
I am using the serial cable the modem came with for hooking up to the
dialler. One more interesting thing I
don’t understand is when the dialler
is hooked up to the modem through
its own serial cable, the SD and RD
lights on the modem flash every time
the LED on the dialler flashes while
it’s looking for the modem. However
when I make my own serial cable (not
XOVER): pins 2-2, 3-3, 5-5, then the
SD and RD lights on the modem do
not flash. Is this a Dialler to Modem
Communication problem?
• The alarm dialler uses the AT command set in terse mode. That is, the
response from the modem must be in
single digit numbers not in words.
For example OK is a 0 (zero). When
August 2006 123
4-Digit Tacho Has Microcontroller Fault
I hope you can assist me with
the 4-Digit Tacho described in the
April 2000 issue. I made it up and
it appeared to be working OK but
in trying to set up the calibrations
I have run into trouble.
When it was first turned on, I set it
for a 4-cylinder motor and it seemed
to be working. I then tried a couple
of the other adjustments and now
I cannot seem to get back to basics
again; eg, I now want to set it for
8-cylinder operation.
How can I reset the micro to the
the alarm dialler is first turned on
it sends out AT and waits for a zero
response. As you have noted this can
be simulated by typing zero on the
PC when you are directly connected.
Only when the alarm dialler gets the
zero will the LED flash quickly and go
into scan mode.
As you have discovered, you can
fool the dialler by sending it a zero
0
00
$10 I Z E
P R OL!
PO
defaults and start from scratch? For
instance, now when I turn it on I get
--00 on the display and all LEDS lit
and after a while it reverts to 000
with no LEDs. Any help would be
appreciated. (G. B., via email).
• If you cannot change the settings
with the up or down switches,
then perhaps the PIC needs to be
reprogrammed. You should be able
to change the “0” to any number
between 1 and 12. If not, return the
PIC to your kit supplier for reprogramming.
from the PC and if you keep it powered you can then plug it back into the
modem and it will work as expected.
So the problem you are experiencing
is that the alarm dialler is not seeing
a zero when it sends an AT request.
There are probably only two causes:
(1) the modem is not programmed to
respond in terse mode. Try connecting
your PC directly to the modem and
entering AT. If you get OK, then the
modem is not configured correctly.
(2) there may be a cable problem. The
alarm dialler uses a 9-pin connector,
whereas most modems use a 25-pin
connector. The important thing to
note is that the send and receive pins
are reversed between 9 and 25-pin
connectors. So you can’t simply connect pins 2 to 2 and 3 to 3. You need
to have them reversed. If the cable is
not correct then you will not be able
to communicate.
When a device is talking to a modem
the SD (send data) and RD (receive
data) LEDs normally flash. This is
because the characters sent into the
modem are echoed back to the device.
If you don’t see any LEDs flash then
the cable is wired incorrectly.
High-voltage
meter wanted
Do you have a circuit for a highvoltage voltmeter that can measure up
to 5kV? I need to know the voltage from
a voltage multiplier that I am working
on. The maximum voltage that I would
like is about 3kV, so a full-scale meter
2006 SILICON CHIP
Excellence in Education Technology Awards
NOW OPEN
SILICON CHIP magazine aims to promote the education, development and application of electronic
technology in all fields throughout Australia. As part of that aim, we are announcing the SILICON CHIP
Excellence in Education Technology awards, with a prize pool of $10,000. Separate awards will be made
to students of secondary schools throughout Australia and to students of universities and TAFE colleges
throughout Australia.
AWARD FOR
EXCELLENCE
The secondary school awards will have three categories:
(a) Best final year assignment of an individual student involving electronics technology
(b) An award to the school sponsoring the winning individual student
(c) Best school project involving electronics technology
The university and TAFE college awards will have three categories:
(a)
Best project from a student as part completion of a degree, diploma or certificate in electronics or
a related field (ie, mechatronics)
(b) Best research project from a post-graduate student working in an area of applied electronics
(c) An award to the university faculty or school sponsoring the best research project.
Entries and judging
The awards will be judged by the editorial staff of SILICON CHIP, convened as a judges panel.
The decisions of the judges will be final.
Entries for the 2006 awards are now open, with final submissions to be made by September 30th, 2006.
All submissions will be confidential, until the winners are announced, in the December 2006 issue of
SILICON CHIP.
Each award will take the form of a cash prize and a commemorative plaque. All enquiries about these
awards should be directed to the editor via email to: awards<at>siliconchip.com.au
124 Silicon Chip
siliconchip.com.au
readout of 3kV would be good. (R. B.,
via email).
• We have not produced a high-voltage meter. However, in May 1999, we
published three electric fence testers
which could do the job. Alternatively,
you could use the resistive divider
string in one of them as a voltage divider to be used with a conventional
digital multimeter.
Mesmeriser clock
has faulty LEDs
I have built the Mesmeriser Clock
featured in your June 2005 issue and I
have a problem. The “seconds” circuit
is working great, doing everything it
should. My problem is in the four
digits. There are quite a few LEDs that
don’t come on at all. In fact, 26 LEDs
don’t come on.
I have checked my work over and
over and even replaced U6 which is
responsible for the digits. I would
appreciate it if you could point me in
the right direction on what I should be
checking. (J. T., Renmark, SA).
• The fact that the circle LEDs all
work indicates that the column drivers (Q1-Q5) are working OK. We must
therefore assume that the problem is
related to the row drivers (U6). How
you now proceed depends on what test
equipment that you have available.
First, disconnect power and measure the resistance between each output
of U6 (pins 10-16) and ground. It’s
possible that one output is shorted to
ground somewhere on the PC board
and the chip is being destroyed. Next,
use your meter to do a continuity
check between pin 8 of U6 and ground.
Perhaps the IC socket is faulty and the
ground pin is open circuit.
If you have an oscilloscope or logic
probe, power up and trace the signal
lines back from the non-operational
LEDs. You should immediately be able
to see where the problem lies. We’d
also suggest removing the PIC from its
socket and checking for bent pins or
damaged contacts in the socket.
Using microwave
transformers in a welder
I am looking to buy an inverter “stick”
welder but they are quite expensive
compared to a traditional transformer
type. I have come across an article on
the web at http://www.dansworkshop.
com/Homebuilt%20arc%20welder.
shtml and I wonder whether you could
comment on its design, safety, etc.
Is this a possible project for the “Salvage It” column as it could save several
microwave ovens from being entirely
scrapped. (R. C., via email).
• At first sight, building a welder from
recycled microwave oven transformers
is an attractive idea – it saves all those
transformers. However, as pointed out
in the link you sent, the transformer
secondaries must be removed and
rewound and then quite a lot of other
stuff added to get a workable unit. By
the time you buy all the necessary bits,
you could easily end up paying more
than $100 to get a unit which is pretty
much a Heath Robinson affair.
By contrast, you can pick up welders very cheaply on eBay and elsewhere and they would be safe and
work well.
Even apart from the dubious value,
we would be reluctant to advocate
people rewinding microwave transformers. Inevitably, someone would
energise the unmodified transformer
Notes & Errata
RFID Security Module, June 2004:
on the overly diagrams (Figs. 2 &
3), diode D3 should be labelled D2
and vice versa.
and that is an exceedingly dangerous
act.
Transistor equivalents
for PN100 and PN200
Could you possibly tell me some
equivalents for the PN100 and PN200
transistors used in the Slave Flash
Trigger, in the July 2003 issue? I live
in the UK and can’t find PN100 and
PN200 here. (E. J., via email).
• Both the PN100 (NPN) and PN200
(PNP) are low-cost general-purpose
bipolar transistors in the TO-92
plastic package, sold here as “multireplacement” types. They both have
a Vcbo rating of 45V, a maximum Ic
rating of 500mA, and an hfe (beta
current gain) range of 80-600 at 10mA
collector current.
Here are some of the common devices listed as electrical equivalents
but note that some of them may not
be suitable for all applications. Some
also have different lead connections,
so you’ll need to check this as well:
PN100 - 2N2222, PN2222, PN3565,
2N3704, 2N3904, BC337, BC547.
PN200 - PN2907, 2N2907, 2N3906,
BC327, BC557, 2N3702.
For reference, the pin connections
for the PN100 and PN200 are both CB-E when viewing the transistors from
below, with the ‘flat’ side downwards
SC
and reading from left to right.
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 Trade Practices Act 1974 or as subsequently amended and to any governmental regulations which are
applicable.
siliconchip.com.au
August 2006 125
MARKET CENTRE
Cash in your surplus gear. Advertise it here in Silicon Chip.
CLASSIFIED ADVERTISING RATES
Advertising rates for these pages: Classified ads: $27.00 (incl. GST) for up to 20
words plus 80 cents for each additional word. Display ads: $49.50 (incl. GST) per
column centimetre (max. 10cm). Closing date: five weeks prior to month of sale.
To book your classified ad, email the text to silicon<at>siliconchip.com.au and include
your credit card details, or fax (02) 9939 2648, or post to Silicon Chip Classifieds,
PO Box 139, Collaroy, NSW, Australia 2097.
_____________ _____________ _____________ _____________ _____________
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Enclosed is my cheque/money order for $__________ or please debit my
o Bankcard o Visa Card o Master Card
Card No.
Signature__________________________ Card expiry date______/______
Name _____________________________________________________
Street _____________________________________________________
Suburb/town ___________________________ Postcode______________
Phone:_____________ Fax:_____________ Email:__________________
126 Silicon Chip
FOR SALE
More control solutions for you!
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Free software, Labview driver and dll
component.
N1500LC Load Cell Panel Meter: New
Low Cost, Great Accuracy, Fully programmable Indicator with 4-20mA and
2 relay outputs.
USB to RS422/RS485 converter: with
1500V Isolation, RTS or Auto Data Flow
control. Heaps of other features.
Electronic Thermostats: with digital
temperature displays, 2 control relays,
can be used in heating and cooling. NTC
thermistor or J TC or Pt100 sensors.
Temperature and Humidity Sensors:
Great accuracy, 4-20mA output. Wall
and Duct mounting available.
Signal Conditioners non isolated
and isolated: convert thermocouples,
RTDs to 4-20mA or 0-10V Fully programmable.
Stepper Motors: we have a selection
of Stepper motors for hobby and high
torque CNC applications.
DC Motors for both hobby and high
torque applications.
DC, Stepper and Servo Motor controller kits.
Counter and Timers: 7-digit and 10year battery operated.
Multi Function Timer and Cyclic Timer/
Pulse Generator
Serial and Parallel Port relay controller cards.
Pump and Trip Alarm controller card.
Duty-Standby operation.
PIC MicroProgrammers: serial and
USB port operated.
2, 4 & 8 Relay Cards: suitable for TTL
and Open Collector Outputs.
Switch Mode, Battery Chargers and
DC-DC converters.
Full details and credit card ordering
available at www.oceancontrols.com.
au. Helping to put you in control.
WEATHER STATIONS: windspeed & direction, inside temperature, outside temsiliconchip.com.au
SPK360
3/5/06
1:10 PM
Page 1
Adjacent
Channel
Filters
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Garran ACT 2605
0412269707
distribution amps - splitters
digital standards converters - tbc's
switchers - cables - adaptors
genlockers - scan converters
bulk vga cable - wallplates
K Series
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Specialising in UK, US and Danish brands.
Speakerbits are your vintage, rare and collectable speaker
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VIDEO - AUDIO - PC
Laceys.tv
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Tel (03) 9776 9222 web:www.laceys.tv
also Sydney, CoffsHarbour, Ulverstone
Satellite TV Reception
International satellite
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Send for your free info
pack containing equipment catalog, satellite
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We can display all satellites from 76.5°
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AV-COMM P/L, 24/9 Powells Rd,
Brookvale, NSW 2100.
Tel: 02 9939 4377 or 9939 4378.
Fax: 9939 4376; www.avcomm.com.au
‘Kinetic’ ADS-B Virtual
Radar Tracking Portable Receiver
MD12 Media Distribution Amplifier
QUEST
®
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DVS5c & DVS5s
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Video / S-Video
and Audio Splitters
Affordable $1250,
easy to install,
connects to laptop/
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USB.
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Phone: (03) 9872 3233.
Quest AV®
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VGS2
HQ VGA
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AWP1
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Products, Specials & Pricelist at www.questronix.com.au
fax (02) 4341 2795
phone (02) 4343 1970
email: questav<at>questronix.com.au
ELNEC IC PROGRAMMERS
High quality
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Free software updates
Large range of adaptors
Windows 95/98/Me/NT/2k/XP
CLEVERSCOPE
USB OSCILLOSCOPES
2 x 100MSa/s 10bit inputs + trigger
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8 x digital inputs
4M samples/input
Sig-gen + spectrum analyser
Windows 98/Me/NT/2k/XP
IMAGECRAFT C COMPILERS
perature and windchill. Records highs
and lows with time and date as they
occur. Optional rainfall and PC interface. Used by government departments,
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Other models with barometric pressure,
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Watch: phone (03) 9761 7040; fax (03)
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PCBs MADE, ONE OR MANY. Any
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Best high end DIY audio kits
on the planet!
www.aksaonline.com
format, hobbyists welcome. Sesame
Electronics Phone (02) 9593 1025.
sesame<at>sesame.com.au
www.sesame.com.au
RCS RADIO/DESIGN is at 41 Arlewis
St, Chester Hill 2162, NSW Australia
and has all the published PC boards
from SC, EA, ETI, HE, AEM & others.
Ph (02) 9738 0330. sales<at>rcsradio.
com.au, www.rcsradio.com.au
ANSI C compilers, Windows IDE
AVR, TMS430, ARM7/ARM9
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August 2006 127
Do You Eat, Breathe and Sleep TECHNOLOGY?
Opportunities for full-time and part-time positions all over Australia & New Zealand
Jaycar Electronics is a rapidly growing, Australian
owned, international retailer with more than 39 stores in
Australia and New Zealand. Our aggressive expansion
programme has resulted in the need for dedicated
individuals to join our team to assist us in achieving our
goals.
We pride ourselves on the technical knowledge of our
staff. Do you think that the following statements describe
you? Please put a tick in the boxes that do:
Knowledge of electronics, particularly at component level.
Assemble projects or kits yourself for car, computer, audio, etc.
Have empathy with others who have the same interest as you.
May have worked in some retail already (not obligatory).
Have energy, enthusiasm and a personality that enjoys
helping people.
Appreciates an opportunity for future advancement.
Have an eye for detail.
RFMA
Why not do something you love and get paid for it? Please
write or email us with your details, along with your C.V.
and any qualifications you may have. We pay a
competitive salary, sales commissions and have great
benefits like a liberal staff purchase policy.
Send to:
Retail Operations Manager - Jaycar Electronics Pty Ltd
P.O. Box 6424 Silverwater NSW 1811
Email: jobs<at>jaycar.com.au
Jaycar Electronics is an equal opportunity employer and
actively promotes staff from within the organisation.
Advertising Index
Altronics............................. 57,86-89
Amateur Scientist CDs............... IBC
Aspen Amplifiers........................ 127
Av-Comm................................... 127
Dick Smith Electronics............ 34-39
Davis Instruments...................... 126
Dominion Electronics................... 99
Elan Audio.................................... 14
Furzy Electronics........................ 127
RF
Modules Australia
Low Power Wireless Connectivity Specialists
VHF TX1 / RX1
Transmitter & Receiver
TX1 $35+GST. RX1 $65+GST
In stock NOW!
Range: 5km+
TX1 I: 9.5mA
RX1 I: 12mA
Data rate: upto 10Kbps
TX1H - 100mW now available
Applications
Rural
Utilities
Industrial
Commercial
Emergency
Services
Government
UHF TX2 / RX2
Grantronics................................. 127
Harbuch Electronics..................... 69
Instant PCBs............................ 1127
Jaycar ....................... IFC,61-68,128
Transmitter & Receiver
TX2 $19+GST. RX2 $39+GST
In stock NOW!
Range: 300m
TX2 I: 10mA
RX2 I: 13mA
Data rate: upto 40Kbps
TX2A/RX2A also available
RADIOMETRIX: Low Power, License Exempt Radio Modules
JED Microprocessors..................... 5
Laceys TV.................................. 127
Len Wallis Audio........................... 15
Microbric...................................... 57
MicroZed Computers.................... 71
RF Modules Australia, PO Box 1957, Launceston, TAS, 7250.
Ocean Controls.......................... 126
Ph: 03-6331-6789. Email: sales<at>rfmodules.com.au. Web: rfmodules.com.au
Quest Electronics....................... 127
Radio Parts.............................. OBC
12 volt LED lightbars, great for solar/
camping. Nixie clock kit $150. Giant LED
clock kit coming soon – 265mm high
digits! www.ledsales.com.au
FLANAGAN TRANSFORMERS
Australian manufacturer of:
• Transformers 1P / 3P
• DC power supplies
• Custom battery chargers
Phone (02) 9824 1095
www.flanagan.com.au
ezChassis PRE-PUNCHED CABINETS for DIY amplifiers. Three heights,
variants for valve and transistor amplifiers. Supplied with labels, screws
and feet. Also heatsinks, handles and
sockets. www.designbuildlisten.com
RCS Radio................................. 127
POWER LEDs, Super Flux LEDs,
12VDC LED modules & blank PCBs.
Quantity discounts. www.luxtronics.
com.au
RF Modules........................... 59,128
Just fill in & mail the handy order form in this issue;
or fax (02) 9939 2648; or phone (02) 9939 3295 &
quote your credit card number.
128 Silicon Chip
Silicon Chip Bookshop........ 120-121
Silicon Chip Subscriptions........... 55
NEVILLE WALKER KIT ASSEMBLY
& REPAIR:
• Australia wide service
• Small production runs
• Specialist “one-off” applications
Phone Neville Walker (07) 3857 2752
Email: flashdog<at>optusnet.com.au
H Each binder holds up to 12 issues
H SILICON CHIP logo printed on spine & cover
Price: $A12.95 plus $A7.00 p&p per order. Available
in Australia only. Buy five and get them postage
free.
Silicon Chip Binders................... 128
SC Perform. Elect. For Cars....... 119
KIT ASSEMBLY
Silicon Chip Binders
RS Components........................... 29
Silicon Chip Technology Awards. 124
Siomar Batteries............................ 3
Speakerbits................................ 127
Taig Machinery........................... 127
The Loudspeaker Kit.................... 33
Tribotix.......................................... 71
REAL
VALUE
AT
Wavecom..................................... 51
P
Worldwide Elect. Components....... 7
$12.95
PLUS P
&
WES Components........................ 11
PC Boards
Printed circuit boards for SILICON
CHIP projects are made by:
RCS Radio Pty Ltd. Phone (02) 9738
0330. Fax (02) 9738 0334.
siliconchip.com.au
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