This is only a preview of the September 2009 issue of Silicon Chip. You can view 33 of the 104 pages in the full issue, including the advertisments. For full access, purchase the issue for $10.00 or subscribe for access to the latest issues. Items relevant to "High-Quality Stereo Digital-To-Analog Converter, Pt.1":
Items relevant to "Using A Wideband O₂ Sensor In Your Car, Pt.1":
Items relevant to "Autodim Add-On For The 6-Digit GPS Clock":
Items relevant to "3-Channel UHF Rolling-Code Remote Control, Pt.2":
Purchase a printed copy of this issue for $10.00. |
And now for something completely different similar!
Putting PEBBLE to work!
Mount a Seismograph on a Protoboard, PEBBLE it
then transfer it to a KPB. What’s a KPB? Read on!
by Stan Swan
A
powerful 7.8 magnitude
earthquake – the biggest experienced in the Shaky Isles
for 80 years – occurred in southern
New Zealand during the early evening of July 15th last. Had you owned a
Seismograph, you might have known
about it virtually straight away.
The earthquake fortunately struck in
a very remote part of the South Island
(Dusky Sound-Fiordland) and damage
was minor, with no injuries or deaths.
Few Kiwis in the more populous
North Island even felt it! However as
a tribute to the massive power of the
event, it transpires that this NZ region
has been measurably twisted slightly
out-of-shape.
Once the shaking settled, the net
result in that region has been a land
raising of about a metre, along with
a sideways shift westward approximating a handspan. Yes – NZ is now
(fractionally!) closer to Australia.
With memories of the Boxing Day
2004 magnitude 9.3 Indian Ocean tsunami still painfully fresh, Australian
east coast alerts (and even some precautionary Lord Howe Island evacuations) promptly developed.
Thankfully these concerns proved a
false alarm, as only mere surges – no
This map shows
the locations of
the Australian and
Pacific Plates, with
the site of the NZ
July 15 earthquake,
right at the junction
of these plates.
higher than normal ocean waves –
eventuated trans-Tasman.
However, closer to the quake source,
waves of 1m high were experienced,
and even in remote Hawaii handspanhigh rough water was noted. The event
served as an excellent test run of the
Australian Tsunami Warning System
(ATWS) and as a reminder that devastating earth movements can strike at
any time, with no warning.
New Zealand sits above an area of
the earth’s crust where the Pacific and
Australian tectonic plates collide and
earthquakes are a regular occurrence.
Kiwis reckon lots of small quakes
(to relieve pressure) are better than
a single large rumble! The Dusky
Sound quake was certainly no mere
pebble splash however and it has triggered renewed interest in earthquake
monitoring overall, perhaps even with
an eye on the holy grail of eventual
prediction.
Seismograph
We mentioned before a Seismograph
which is, of course, a device used to
The Kiwi Patch Board, a PC board which is has the same hole
spacing as a 23-way Protoboard but has many extra features.
It can be used to transfer protoboard layouts to PC boards.
72 Silicon Chip
siliconchip.com.au
both monitor and, with the right equipment, measure earth movements.
Readers may recall the September
2005 SILICON CHIP Seimograph article
by Dave Dobeson. This detected delicate earth movements and vibrations
by pendulum displacement, with
deviations optically monitored by a
LED/LDR combination.
These READADC values were
then handled by an opamp and
PICAXE-08M to yield a classic earthquake “squiggly line” seismic trace
display.
Dave’s design is still perfectly valid
and motivated readers may already
have nervously thumbed through dog
eared SILICON CHIP magazines looking
for details. But wait – here’s a fresh
layout approach involving PEBBLE!
Kiwi Patch Board
Taking the breadboard/protoboard
concept one step closer to permanency,
a so-called “Kiwi Patch Board”(KPB)
has now been developed which essentially allows the direct transfer of
the classic 23 x 10 breadboard layout
onto a PC board which has exactly the
same hole pattern and spacing.
The KPB is a quality fibreglass and
silk-screened PC board measuring
~90mm x 45mm. It has many “extras”
over the breadboard, including space
for a 7805 regulator and smoothing
capacitor (or other 3-pin regulator if
you aren’t using a PICAXE), 3.5mm
PICAXE programming socket, screw
PEBBLE diagram of the Simple Seismograph (SILICON CHIP September 2005)
control transferred to protoboard – but exactly the same layout can be used to
populate a Kiwi Patch Board. There’s also room for the “extras” such as the
voltage regulator, sensitivity pot, programming socket, etc.
terminal, header pin and support
mounts, dual supply and even extra
rails under the IC.
The KPB is now available in Australia from MicroZed and sells for $6.75.
The approach involves doing initial
circuitry development on a solderless
breadboard,using PEBBLE as a layout
refinement aid. The advantage of this
technique is that components and
links on the final working breadboard
design can then be progressively
swapped over and soldered onto a
the KPB. Such “paint by number”
style assembly can be very confidence
REG1 7805
100
D1
1N4004
IN
+5V
OUT
IN
LED1
K
boosting!
Of course, this goes against traditional PC board design somewhat
which call for as few links as possible
– but being able to switch between
breadboard and patch board with
exactly the same appearance means
much less likelihood of misteaks misstakes misst . . . errors.
In fact mounted circuitry can look
so professional that projects may not
even progress to a dedicated PC board.
Educational acceptance of the KPB
has been very strong here in NZ.
Kiwi educators, keen to both improve
GND
GND
A
LDR1
OUT
100nF
10k
K
470F
9V
DC IN
470F
CON1
SERIAL
OUTPUT
CON2
DB9F
SENSITIVITY
VR1 100k
A
470F
25V
7805
VANE
ON
SEISMIC
MASS
1
6
10k
2
7
3
IC1
741
4
6
VR2
5k
4
3.3k
1k
10k*
(SEE TEXT)
3
Vdd
P0
P1
P3
2
3
IC2
5
PICAXE P2
-08M
SER 2
IN
P4
Vss
5
22k
8
H
L
E
10k
7
3.3k
10k
LED
SC
2005
SIMPLE SEISMOGRAPH
LOGGER
OUTPUT
1N4004
A
K
K
A
The circuit diagram of the Simple Seismograph, reproduced from the September 2005 edition of SILICON CHIP. Refer to
that issue for complete operational details and the seismic mass which drives it.
siliconchip.com.au
September 2009 73
JOIN THE TECHNOLOGY
AGE NOW
with
PICAXE
Developed as a teaching tool,
the PICAXE is a low-cost “brain”
for almost any project
Easy to use and understand,
professionals & hobbyists can
be productive within minutes.
Free software development
system and low-cost in-circuit
programming.
Variety of hardware, project
boards and kits to suit your
application.
Digital, analog, RS232,
1-Wire™, SPI and I2C.
PC connectivity.
Applications include:
Datalogging
Robotics
Measurement & instruments
Motor & lighting control
Farming & agriculture
Internet server
Wireless links
Colour sensing
Fun games
Ben, a 17 year old electronics student at Hutt Valley High School, Wellington,
NZ, finds putting it all together is so simple when he has PEBBLE to guide him.
presentation and ease the agony many
electronics novices experience with
circuit construction, were predictably
behind the KPB design.
PEBBLEing the
Kiwi Patch Board
Although PEBBLE is essentially
intended for basic breadboards, it’s
been satisying to also have the moreinvolved KPB layout available under
this versatile emulator. PEBBLE’s save
and load facility pleasingly also allows designs to be emailed or set up
as templates.
Given the intended PICAXE slant
of the KPB, the two resistors and inverted 08M programming layout may
especially suit the latter. To further
ease the quest, some components (in
particular the screw terminals, 7805,
smoothing capacitor and programming
socket) have been pre-mounted.
If these are unwanted then a
trimmed KPB board can be selected
from PEBBLE’s offerings.
KP-Boarding the Seismograph
Distributed in Australia by
Microzed Computers
Pty Limited
Phone 1300 735 420
Fax 1300 735 421
www.microzed.com.au
74 Silicon Chip
Components in the original 2005
earthquake detector were shown soldered onto a dedicated PC board and
run from an unregulated 9-15V supply.
Programming can be via the 3.5mm
socket but an input has also been provided to suit the header pin style used
in many SILICON CHIP PICAXE articles.
Component placement onto a KPB
under PEBBLE was almost “paint by
number” but the ability to juggle board
layout proved very gratifying.
Such “cut and try” versatility,
normally requiring extensive pen
and paper planning and tedious wire
stripping, made for great productivity.
The bonus of a large-screen board
view furthermore eased eye strain.
Aside from the supply rail red and
ground black, most wire colours
shown here are not sacred and were
simply selected for functional clarity.
Many alternative layouts are possible for this circuit but with a further
ground rail assigned in the channel
under the ICs, the eventual wiring
became very clear and direct. Readers with a keen eye for such things
are encouraged to relate to this new
PEBBLE version to both the schematic
and original layout.
NZ’s well known tectonic tendencies, also manifested as significant
volcanic and thermal activity, means
comprehensive monitoring systems
have long been warrented here.
Both Civil Defence alerts and web
based seismic services (www.geonet.
org.nz) are well established, perhaps
reducing the need for a personal seismometer within NZ.
Coastal Australian readers of a nervous disposition however may already
have their soldering iron out and
warming up . . .
Resources, credits and references
are hosted at www.manuka.orcon.net.
nz/seismo.htm
SC
siliconchip.com.au
|