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Items relevant to "Follow-up: Quantum-dot Cellular Automata":
Items relevant to "Battery Multi Logger":
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Letters and emails should contain complete name, address and daytime phone number. Letters to the Editor are submitted on the condition that
Silicon Chip Publications Pty Ltd may edit and has the right to reproduce in electronic form and communicate these letters. This also applies to
submissions to “Ask Silicon Chip”, “Circuit Notebook” and “Serviceman”.
Harbuch Electronics ownership change
I just got the following email from Harbuch Electronics [edited for brevity and grammar – Editor]. It is great to
know it will survive. We can ill afford any more losses in
Australian electronics manufacturing.
Hugo Holden,
Minyama, Qld.
Hi there, I’m sending you this email because you have
dealt with Harbuch Electronics in the past and I wanted
to update you on some recent changes.
Unfortunately, the previous owner, Peter Terlich, fell seriously ill in May and couldn’t return to work. I was one of
his larger customers through my other business Powerform
Controls – Harbuch was making a current transformer for
us that I had trouble sourcing elsewhere. After discussions
with Peter’s family, I bought Harbuch Electronics.
I love Australian manufacturing and have taken on
Harbuch Electronics, aiming to continue to manufacture
high-quality transformers locally.
I’ve spent the last 25+ years working as an Electrical
Engineer in various roles. Through Powerform Controls,
we have a well-set-up manufacturing system that we will
move Harbuch across to (Powerform also does all its manufacturing locally).
We plan to continue making nearly all the transformers
and things that Harbuch has made in the past: toroidal
transformers up to 5kVA, E&I transformers, audio transformers, chokes, isolation transformers, powerboards and
more.
We’ve got all the manufacturing records going back 10
or so years – if you had a standard or custom design, we
most likely have the manufacturing info for it. Garth and
Vino, Peter Terlich’s staff, are also working with us.
As a result of this, there is a new company, ABN, bank
account and address. We have moved from Blacktown
to the Powerform Controls factory in Artarmon. The old
Hornsby phone number is our main phone number now,
but the Blacktown landline also works.
The preferred email address is sales<at>powerform.com.
au – it is checked by Tim and myself, so things are less
likely to get missed.
I know Harbuch has let some customers down while
Peter Terlich was sick – if that is the case, I hope you can
give me a chance to restore the business relationship. If
it has been a while since you dealt with us, I’d love to reestablish that relationship and make high-quality transformers for you.
If you’d like to chat about anything, please give me a call.
Peter McConaghy
02 9476 5854
4
Silicon Chip
Smaller toaster oven for DIY solder reflow
Santa was kind enough to buy me a Silicon Chip subscription, so I’m looking forward to more project building in 2021.
At the moment, I am working on the DIY Reflow Oven
(April & May 2020; siliconchip.com.au/Series/343). I got
the controller working pretty well, so I went shopping
for an oven.
I purchased the baby sister of the Kmart oven that you
mention in the article (www.kmart.com.au/product/9litre-oven/2487301). The capacity is much smaller (9L vs
28L), but it has a reasonable amount of power given the
size (1050W vs 1500W) and is half the price ($29 vs $59).
It has upper and lower heating elements, but they didn’t
have room for the knob to select which elements are active. It is big enough for most circuit boards, and I can fit
it more easily (space is at a bit of a premium at my place).
My initial testing shows that it works fine using the PID
parameters from the article. I think this is a better-suited
oven for reflowing, mostly due to there being less empty
space above the PCB.
Thanks for all your hard work on these fantastic projects, and have a Happy New Year!
Stephen Gordon,
Thurgoona, NSW.
Free circuit drawing and simulation software
Around June 2019, Spectrum Soft called it quits and
have released their Integrated Schematic Editor and Circuit Simulation software, Micro-Cap 12, for free. They
have been in the business since the 1980s. Micro-Cap 12
used to retail for US$4,500 (about $6000).
This is too good to miss. You can download it from www.
spectrum-soft.com/download/download.shtm
This is a great way to get one of the best schematic editors and simulation packages on the market.
I found this info just by sheer luck on the But KIS Analog
YouTube channel: siliconchip.com.au/link/ab62
They have several tutorials on Micro-Cap 12, with more
in the pipeline.
Greg Gifford,
Laguna, NSW.
Android app for calculating resistor values
In the October 2020 Ask Silicon Chip column, R. M. of
Melville WA asked for a BASIC program to calculate series/parallel resistor values.
This prompted me to create Android apps for calculating series and parallel resistance using App Inventor (as
described in the article I wrote, starting on page 74 of this
Australia’s electronics magazine
siliconchip.com.au
issue). You can download these Apps from the Silicon
Chip website under February 2021.
The download package includes the Android .apk files
and also the App Inventor .aia project files. These can be
imported into App Inventor to make modifications by
clicking on “My Projects”, then selecting “Import project
(aia) from my computer”.
Roderick Wall,
Mount Eliza, Vic.
BoM tide data outage
On the morning of January 1st 2021, I got a message saying “Error – data not available” on my Raspberry Pi-based
Tide Clock (July 2018; siliconchip.com.au/Article/11142).
Our internet service is working OK.
It started working again all by itself on the 3rd. I guess
the Bureau of Meteorology shut the server down at midnight for the new year. It was down for at least one day.
Roderick Wall,
Mount Eliza, Vic.
Helping to put you in Control
PR200 programmable relay 230VAC
A programmable logic relay with 8DI
+ 8DO + 4AI + 2AO (4-20 mA), LCD,
2x RS485 (Modbus RTU/ASCII) ports
and 230VAC powered. Free easy to use
Function-Block Software.
SKU: AKC-002
Price: $399.95 ea + GST
Simex SLI-8 8 Counter Modbus RTU module
An 8 isolated digital input module with Modbus RS485
communications. Provides a non volatile 32 bit counter
for each input. 24VDC powered.
SKU: SID-003
Price: $239.95 ea + GST
Getting into soldering SMDs
I was always reluctant to try a Silicon Chip project that
used SMDs, as I baulked at soldering those tiny components.
However, when I saw the DAB+/FM/AM radio project,
even though it bristled with SMDs, it was just what I was
after, so I decided to give it a go.
After buying the parts, I went to YouTube to see how to
solder SMDs. I settled on the solder paste method. After
buying some paste, I gave it a go. It was easy enough, but
I had trouble keeping the components from moving while
soldering, resulting in a wonky joint. After a while, I devised this system:
1. Put a dob of solder paste on the pads.
2. Locate the SMD.
3. Hold it down with the point of a scriber held vertically.
4. A few seconds with the soldering iron on the pins
and the job’s done.
With a hand on the top of the scriber, hand movement
will not affect the component, and the soldering iron does
not move the component.
After I finally got the radio going, I noticed one channel was not working. I traced the trouble to a faulty SMD
IC, which meant it had to be replaced. So I went back to
YouTube to see how to remove an SMD IC. I settled on the
desolder wire method.
After buying some, I laid it along the IC’s pins and heated it with the soldering iron. The low melting point of the
wire causes it to diffuse with the existing solder, and in no
time, the IC lifted and floated to the side; a quick clean up
with solder wick and it was ready for soldering the new IC.
I learned a lot from this project, and am not reluctant to
try others in the future.
Trevor Vieritz,
Burpengary, Qld.
Comment: we are glad to hear that you got the radio working and are more comfortable working with SMDs, but you
should be aware that there are problems with both methods described.
We do not recommend using solder paste with a soldering iron. It is designed to be heated more slowly by hot air
or infrared reflow, so the flux formulation is different. You
siliconchip.com.au
SPT-61 Transmitter PT100/500/1000
The SPT-61 signal converter is equipped with
Pt 100 / Pt 500 / Pt 1000 type input, 4-20mA
output. Loop powered.
SKU: SIB-001
Price: $134.95 ea + GST
BACnet MSTP Slave/Modbus Master - Converter
The HD67671-MSTP-4-A1 BACnet Slave / Modbus Master
Converter allows you to integrate a BACnet network with a
Modbus net. It allows you to connect a BACnet Master (for
example a Supervisory System...) with some
Modbus slaves.
SKU: ADW-001
Price: $586.80 ea + GST
AirGate Modbus (Gateway RS-485/
Wireless)
Wireless gateway for extending Modbus
networks. USB and RS-485 interfaces.
SKU: NOW-001
Price: $473.50 ea + GST
1-port isolated RS-422/485 Modbus Gateway
Modbus TCP to Modbus ASCII/RTU converter gateway allows
Modbus TCP masters to communicate
with serial Modbus slave devices via
isolated RS-422/485 interfaces with TB5
screw terminals.
SKU: ATO-162
Price: $330.00 ea + GST
Loop Powered 4-20mA Surface Temperature Sensor
This is a simple 4-20mA output loop
powered temperature sensor with
measurement range from 0°C to +100°C
designed for monitoring battery, heatsink
and surface temperatures.
SKU: KPS-015
Price: $83.00 ea + GST
For Wholesale prices
Contact Ocean Controls
Ph: (03) 9708 2390
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Prices are subjected to change without notice.
Australia’s electronics magazine
February 2021 5
also risk flinging tiny solder balls all
over the board, which is particularly
bad for boards carrying high voltages
as it could lead to arcing.
The problem with desoldering wire
is that once you have melted it into the
solder on the board, it’s impossible to
remove completely. It will change the
formula of your solder, possibly leading to premature solder joint failures.
Desoldering SMDs is very easy, quick
and safe with a low-cost hot air wand.
It can also be done with regular solder
with some practice.
BWD602 circuit diagram needed
I love your magazine. I was wondering if any of your readers have a circuit diagram or manual for a BWD602
combination instrument. I am repairing one that I bought recently, and the
diagram would be a great help. I am
trying to build a collection of BWD instruments while some are still around,
and am looking for more instruments
if the price is right.
Trevor Collins,
Bellevue, WA.
Comment: one of our readers, Bruce
Williams, suggested it was a rebadged version of a Hung Chang OS650 oscilloscope from South Korea
(siliconchip.com.au/link/ab63). It
was also badged as Aron BS-601 or
ProTek 6502.
He included some PDFs of various
manuals which can be downloaded
for free from our website: siliconchip.
com.au/Shop/6/5755
Trying to avoid price increases
In your January editorial, you asked
for feedback upon the content. I find
the balance to be about right, and as a
pensioner, I certainly would not like
to see a larger publication with an attendant increase in price! Like you, I
am surprised that it has been steady
for so long.
I do not read every article; for example, I’m not interested in the audio articles with cabinet making etc, but to
each his/her own. The Vintage Radio
section is quite interesting as is Circuit Notebook, along with the queries
in Ask Silicon Chip (I have learned a
great deal from the answers).
One minor gripe is about the need
for Windows to run some of the projects; many people refuse to run it due
to its inherent bugginess and security
problems. I understand that you have
no control over the software that con6
Silicon Chip
tributors use, but hopefully, some will
see the light and make versions for better operating systems such as Linux,
Mac, FreeBSD etc.
All in all, the magazine balance is
just about right.
Dave Horsfall,
North Gosford, NSW.
Nicholas comments: As mentioned in
a couple of editorials, I am putting off a
cover price increase, but it will have to
happen eventually. See the graph below showing the magazine cover price
in 2020 dollars over time (calculated
using the RBA’s inflation statistics).
As you can see, the current cover
price is the lowest it has been since
1996 in real terms (that was before the
GST was introduced).
Most of our projects which involve
computer software these days will
work on Windows, Mac or Linux. For
example, the Arduino-based Adjustable Power Supply in this issue, the
Flexible Digital Lighting Controller
from October & November 2020 (except for the optional sequencing software reused from 2010) etc.
Those all use software written in
Processing which works in multiple
different operating systems. Windows
programs can often also be run on Mac
systems (eg, via Bootcamp) or Linux
(using WINE).
Feedback on magazine content
I’d like to comment about your Editorial Viewpoint in the December
2020 issue.
I started electronics as a hobby when
I was a teenager in the early 1990s, and
at that time, I had a subscription to a
French electronics magazine. I did not
understand much of the schematics, so
I bought some books to learn. It was
only after I earned a master’s degree
in microelectronics and digital communications that I really understood
Australia’s electronics magazine
the magic behind the transistors and
other components.
Many years later, in 2015, I came
back to my hobby, and I was looking
for a new magazine to subscribe to.
Sadly, the magazine I previously subscribed to (Electronique Pratique) had
ceased publication. Then I discovered
Silicon Chip.
Browsing the various issues, I could
see many projects published in the
magazine, some of the more complex
ones over several issues. Some publications did not place much emphasis
on projects, but rather technical articles instead. I also liked having the
possibility to buy the PCBs and download the software. I thought that was
a huge plus.
Since I moved to Singapore and
now live in a condo, I could not easily make my own PCBs anymore, but
now it’s easy and relatively cheap to
have them made.
So I immediately took a subscription
to Silicon Chip, and five years later, I
have built many of your projects. I have
to say I am delighted with the content
of the magazine so far. I appreciate
the balance between various types of
projects and technical articles, Circuit
Notebook, Ask Silicon Chip etc.
What I really enjoy are those complex projects you publish over several
issues, like the recent USB SuperCodec and its Attenuator board over five
issues, or a few years back the great
series of articles on the Mk4 UltraLD amplifier, the preamp, the power
supply board and the speaker protection module.
That was an amazing project that
I built together with your 8-octave
equaliser, LED VU meter and CLASSiC DAC! I had a great time building
and testing all of them. You even published some pictures of my finished
products (twice).
Now there are also tons of smaller
projects that are appealing for not only
low-experienced readers and newbies,
but also experienced ones. There’s
something for everyone.
I appreciate that you support your
readers, not just by selling PCBs and
supplying source code but also supplying hard-to-find parts, PCB layouts and
answering readers’ questions. I work in
the financial software world (trading
platform), and support makes a huge
difference between vendors, so does
it for magazines, I believe.
So I would not like to see you reduce
siliconchip.com.au
the number of projects from four. If you
could increase the number of projects,
that would be great! As I also enjoy the
other sections of the magazine, I would
like to see the number of pages increasing, like what you did a few times in
the past with some issues.
Consequently, I would be supportive if you increase the cover price with
more content. As you said, the cover
price has not increased in seven years.
Not that this is a reason to do so now,
but if you were to do so, I think most
readers would understand.
If you increase the price and add
more pages, and thus more content, I
believe most of the readers would understand that they have now more for
their money.
By increasing the number of pages,
you might gain more readers, especially if that allows you to increase
the variety of articles.
For those who are very price-sensitive, there is always the option to subscribe online. That may not be the taste
of all, but it’s an alternative.
Olivier Aubertin,
Singapore.
VHF masthead amplifier works for DAB+
My boat is moored at Hastings on
Western Port Bay, which is on the edge
of DAB+ reception from Melbourne.
Some times I can receive both multiplexes, sometimes the lower one, and
often neither.
I am using a 3-element Yagi, vertically polarised. Part of the problem is
that it is looking out through a forest
of aluminium masts, most with wire
rigging.
You recommended (in response to a
query) that I use a VHF masthead amplifier to improve DAB+ reception. I
did that, and it appears to be working
well. Thanks for your advice.
Geoff Champion,
Hastings, Vic.
Latest PICs & GPS disciplined
oscillator
I just read the article about the
latest 8-pin PICs (November 2020;
siliconchip.com.au/Article/14648). I
have been testing out the PIC16F1455
lately – you’ve used it in several
projects over the last few years, so I
thought I’d see how it compared to the
PIC16F628A I’d been using previously.
I’m using it to build a much simpler
GPS disciplined oscillator than the one
you published in Circuit Notebook,
siliconchip.com.au
July 2020. It consists of little other
than the 16F1455, a GPS receiver, an
OSC5A2802 10MHz VCO and a thirdorder passive RC low-pass filter to convert PWM from the micro to a smooth
control voltage for the oscillator. I
think it’s about as simple as can be.
The parts are quite cheap. Apart
from the power supply, the total cost
is less than $20, and who doesn’t have
a 5V 1A power supply hanging about?
The NEO-6 GPS receiver is a 3.3V
part, so its TX data was marginal to
drive the 5V PIC’s serial RX, a Schmitt
trigger input. I got around that by creating a 9600 baud software UART using one of the input-only pins used for
USB when USB is enabled. It operates
as a TTL input, so it is quite happy receiving data at 3.3V.
The 1PPS output of the GPS receiver is fed to the PIC’s internal comparator, with the other input being held at
1.9V by the internal DAC. The PIC is
clocked from the 10MHz VCO, and it
has an internal x4 PLL, giving a nominal base clock of 40MHz with a 10MHz
instruction clock.
Compared with the PIC16F628A
I was using before, the 16F1455 has
major benefits. The output PWM signal is now 40kHz, so it loops through
the 24-bit dither system three times
per second, and all artifacts disappear
in the filter.
Also, detection of the GPS 1PPS signal uses the gate function of TMR1,
which clocks at 40MHz, so pulse timing can be determined to within 25ns.
So there’s no need for the complex delay system of my previous circuit. The
program evaluates data statistically, so
the uncertainty decreases with more
samples.
The advanced 8-bit PIC architecture
is much better than the PIC16F628A.
Two indirect registers can access all
memory (including program memory)
instead of one that could access 256
bytes. Those registers can be used for
moving data with auto-increment or
auto-decrement. You can also load or
store with an offset.
There are added shift instructions,
eg, logical shifts that don’t require
the carry flag to be set/cleared before
shifting; the older instructions rotated through the carry flag. There’s also
an arithmetic right-shift that propagates the sign.
There are added arithmetic operations that also affect the carry flag. Previously, a multi-byte add or subtract
Australia’s electronics magazine
February 2021 7
required four instructions for all bytes
but the least significant byte; now it
only takes two.
The interrupt system is improved as
much state data is saved when an interrupt occurs; previously, it was necessary to specifically save any register
that the interrupt was going to use, and
restore them on exit. Interrupts can be
serviced without superfluous instructions – some of mine are now less than
10 instructions.
There are new relative CALLW and
BRW instructions that cater to page
boundaries, and there are mechanisms
to do just about anything. Program
memory can be read and written (I
now store constant text strings in program memory as two 7-bit characters
per 14-bit memory location).
The CALL stack can be manipulated,
and the saved status from an interrupt
can be manipulated. The only serious
drawback is the banked memory model.
Any operation involving a peripheral
usually requires the user to change the
bank register to access the peripheral,
and not using the right bank results in
unpredictable behaviour.
You will remember the confusion
about writing assembler code for
MPASM, which is not included in
the latest MPLAB X IDE downloads.
I haven’t seen one positive comment
regarding the replacement assembler,
XC8; the almost universal consensus is
to keep using MPASM as XC8 is only
useful to write embedded assembler
in C programs.
I tried using XC8, but it was all too
hard. I am using a threaded system so
that the NMEA data from the GPS can
be received and processed at the same
time as the mainline is dealing with
the 1PPS data. I couldn’t see how to
make it work with XC8.
Alan Cashin,
Islington, NSW.
A tale of two speed controllers
First, I would like to say that I am
very happy to see a PDF version of the
magazine. Being a constant traveller,
downloading the big file for the online
issue via satellite on a slow shared connection was a problem.
The main reason I wrote in is to say
that just over two years ago, I built the
first version of your Speed Controller
for Universal Motors (February-March
2014; siliconchip.com.au/Series/195).
Putting it together did not present
any real problems, but it didn’t work
8
Silicon Chip
straight away. I ran through the suggested troubleshooting, which was
quite good.
I checked the critical components
with the power off and soon discovered the pots were open circuit. So I
ordered new pots. Once I had replaced
the cabling again, they checked out,
but it still wasn’t working, So I powered it from my bench supply as the
guide suggested. Everything seemed
to be working as it was supposed to,
so I disconnected the bench supply
and made some checks when running
from the mains.
One of the first checks I made was
to see that there was 15V getting to IC3
and REG1, but I only measured 7V. I
had already checked BR2, the 1MW
and 470W resistors and the 220nF capacitors. I thought that there might be
a short or bad component, but nothing
was running hot.
I decided to try paralleling another
220nF X2 capacitor across one of the
two feeding BR2. That gave me 9V
across ZD1; an improvement, but still
not enough. I tried replacing the two
220nF capacitors, but that didn’t help,
So I swapped in 470nF X2 capacitors
instead. Bingo, that did it! The speed
controller was alive. It has been working well ever since.
I was thinking about building another one so when I saw your new speed
controller in the March 2018 issue
(siliconchip.com.au/Article/10998),
and realised that it would be much
cheaper and simpler to build, I decided to go for it. Construction generally went OK, and it worked straight
away, but I noticed that there wasn’t
enough speed control.
The main reason for building it was
to convert a grinder into a polisher. I
was a bit confused about how many
turns were supposed to go through
the current transformer. I had put in
only one turn, and I had trouble with
that. I changed it to two turns through
the transformer core, and that fixed it.
One of the uses I have for it is with
my SDS hammer drill. It’s very good
mechanically, but the contact protection override switch is terrible. Eventually, I will use the controller when
contact detector and switch gives in
totally, plus an earth-leakage circuit
breaker (ELB) if working where I need
the protection.
Neil Brewster,
Footscray, Vic.
Comments: we aren’t sure why you
Australia’s electronics magazine
had to change the 220nF capacitors
to 470nF in the first speed controller.
220nF should be adequate; perhaps
your circuit is drawing more current
than expected, eg, ZD1 may be leaky
or trimpots VR1-VR3 may be lower values than the 10kW specified.
For the second controller, the number of turns through the transformer
is not critical (one or two turns is acceptable). The feedback adjustment
trimpot can be used to compensate
for the difference by reducing the feedback effect when two turns are used.
Suggestion to redo rain gauge
It might be a good idea to revisit
your June 2000 Automatic Rain Gauge
(siliconchip.com.au/Article/4325) and
March 2000 Electronic Wind Vane
(siliconchip.com.au/Article/4354),
perhaps combined with your February 2018 Water Tank Level Meter
(siliconchip.com.au/Article/10963).
You could bring together the three
projects to provide an online weather
station with expanded capabilities.
I think it makes excellent sense to
use the project archive you already
have and bring it forward in time by
making it relevant to current circumstances. For example, by taking the
rain gauge and weather vane projects
and making them internet savvy with
the online data logging functionality
associated with www.thingspeak.com
– you’re ticking many boxes from my
perspective.
Iain McGuffog,
Indooroopilly Centre, Qld.
Comment: we have looked at doing
this sort of thing in the past, but we
stopped when we realised that digital
weather stations are now so cheap.
We know that some people like to do
it themselves, but the idea of spending several hundred dollars and many
hours to build something that you can
buy for $99 at Bunnings is not very
appealing.
Since it would take a lot of work to
revisit such projects properly, we only
want to do so if they will be popular
with readers. Integrating the water
tank level meter might make it more
worthwhile, but keep in mind that the
water level sensor itself is quite expensive (but worth it, in our opinion, as
it is easy to install and works well).
We will investigate this again to see
whether it will be worthwhile, even
though we already know that it doesn’t
make much financial sense.
SC
siliconchip.com.au
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