In this review we examine the three digit counter module kit from Altronics. The purpose of this kit is to allow you to … count things. You feed it a pulse, which it counts on the rising edge of the signal. You can have it count up or down, and each kit includes three digits.
You can add more digits, in groups of three with a maximum of thirty digits. Plus it’s based on simple digital electronics (no microcontrollers here) so there’s some learning afoot as well. Designed by Graham Cattley the kit was first described in the now-defunct (thanks Graham) January 1998 issue of Electronics Australia magazine.
Assembly
The kit arrives in the typical retail fashion:
And includes the magazine article reprint along with Altronics’ “electronics reference sheet” which covers many useful topics such as resistor colour codes, various formulae, PCB track widths, pinouts and more. There is also a small addendum which uses two extra (and included) diodes for input protection on the clock signal:
The counter is ideally designed to be mounted inside an enclosure of your own choosing, so everything required to build a working counter is included however that’s it:
No IC sockets, however I decided to live dangerously and not use them – the ICs are common and easily found. The PCBs have a good solder mask and silk screen:
With four PCBs (one each for a digit control and one for the displays) the best way to start was to get the common parts out of the way and fitted, such as the current-limiting resistors, links, ICs, capacitors and the display module. The supplied current-limiting resistors are for use with a 9V DC supply, however details for other values are provided in the instructions:
At this point you put one of the control boards aside, and then start fitting the other two to the display board. This involves holding the two at ninety degrees then soldering the PCB pads to the SIL pins on the back of the display board. Starting with the control board for the hundreds digit first:
… at this stage you can power the board for a quick test:
… then fit the other control board for the tens digit and repeat:
Now it’s time to work with the third control board. This one looks after the one’s column and also a few features of the board. Several functions such as display blanking, latch (freeze the display while still counting) and gate (start or stop counting) can be controlled and require resistors fitted to this board which are detailed in the instructions.
Finally, several lengths of wire (included) are soldered to this board so that they can run through the other two to carry signals such as 5V, GND, latch, reset, gate and so on:
These wires can then be pulled through and soldered to the matching pads once the last board has been soldered to the display board:
You also need to run separate wires between the carry-out and clock-in pins between the digit control boards (the curved ones between the PCBs):
For real-life use you also need some robust connections for the power, clock, reset lines, etc., however for demonstration use I just used alligator clips. Once completed a quick power-up showed the LEDs all working:
How it works
Each digit is driven by a common IC pairing – the 4029 (data sheet) is a presettable up/down counter with a BCD (binary-coded decimal) output which feeds a 4511 (data sheet) that converts the BCD signal into outputs for a 7-segment LED display. You can count at any readable speed, and I threw a 2 kHz square-wave at the counter and it didn’t miss a beat. By default the units count upwards, however by setting one pin on the board LOW you can count downwards.
Operation
Using the counters is a simple matter of connecting power, the signal to count and deciding upon display blanking and the direction of counting. Here’s a quick video of counting up, and here it is counting back down.
Conclusion
This is a neat kit that can be used to count pulses from almost anything. Although some care needs to be taken when soldering, this isn’t anything that cannot be overcome without a little patience and diligence. So if you need to count something, get one ore more of these kits from Altronics. Full-sized images are available on flickr. And while you’re here – are you interested in Arduino? Check out my new book “Arduino Workshop” from No Starch Press – also shortly available from Altronics.
In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitter, Google+, subscribe for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other – and we can all learn something.
In this review of an older kit (circa 1993~1997) we examine the Diesel Sound Simulator for Model Railroads kit from (the now defunct) Dick Smith Electronics, based on the article published in the December 1992 issue of Silicon Chip magazine.
The purpose of this kit is to give you a small circuit which can fit in a HO scale (or larger) locomotive, or hidden underneath the layout – that can emulate the rumbling of a diesel-electric locomotive to increase the realism of a train. However the kit is designed for use with a PWM train controller (also devised by Silicon Chip!) so not for the simple direct-DC drive layouts.
Assembly
The diesel sound kit was from the time when DSE still cared about kits, so you received the sixteen page “Guide to Kit Construction” plus the kit instructions, nasty red disclaimer sheet, feedback card, plus all the required components and the obligatory coil of solder that was usually rubbish:
Everything required to get going is included, except IC sockets. My theory is it’s cheaper to use your own sockets than source older CMOS/TTL later on if you want to reuse the ICs, so sockets are now mandatory here:
The PCB is from the old school of “figure-it-out-yourself”, no fancy silk-screening here:
Notice the five horizontal pads between the two ICs – these were for wire bridges in case you needed to break the PCB in two to fit inside your locomotive.
Actual assembly was straight-forward, all the components went in without any issues. Having two links under IC2 was a little annoying, however a short while later the PCB was finished and the speaker attached:
How it works
As mentioned earlier this diesel sound kit was designed for use with the Silicon Chip train PWM controller, so the design is a little different than expected. It can handle a voltage of around 20 V, and the sound is determined by the speed of the locomotive.
The speed is determined by the back EMF measured from the motor – and (from the manual) this is the voltage produced by the motor which opposes the current flow through it and this voltage is directly proportional to speed.
Not having a 20V DC PWM supply laying about I knocked up an Arduino to PWM a 20V DC supply via an N-MOSFET module and experimented with the duty cycle to see what sort of noises could be possible. The output was affected somewhat by the supply voltage, however seemed a little higher in pitch than expected.
You can listen to the results in the following video:
I reckon the sound from around the twenty second mark isn’t a bad idle noise, however in general not that great. The results will ultimately be a function of a lower duty-cycle than I could create at the time and the values of R1 and R2 used in the kit.
Conclusion
Another kit review over. With some time spent experimenting you could generate the required diesel sounds, a Paxman-Valenta it isn’t… but it was a fun kit and I’m sure it was well-received at the time. To those who have been asking me privately, no I don’t have a secret line to some underground warehouse of old kits – just keep an eye out on ebay and they pop up now and again. Full-sized images and much more information about the kit are available on flickr.
And while you’re here – are you interested in Arduino? Check out my new book “Arduino Workshop” from No Starch Press.
In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitter, Google+, subscribe for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other – and we can all learn something.
A few weeks ago I was asked about creating a musical-effect display with an RGB LED cube kit from our friends over at Freetronics, and with a little work this was certainly possible using the MSGEQ7 spectrum analyzer IC. In this project we’ll create a small add-on PCB containing the spectrum analyzer circuit and show how it can drive the RGB LED cube kit.
You can get the bare MSGEQ7 ICs from Sparkfun and the other usual suspects. It never hurts to have a spare one, so order two and matching IC sockets. Finally you should be able to translate a simple circuit to prototyping board.
The circuit
The LED cube already has an Arduino Leonardo-compatible built in to the main PCB, so all you need to do is build a small circuit that contains the spectrum analyzer which connects to the I/O pins on the cube PCB and also has audio input and output connections. First, consider the schematic:
For the purposes of this project our spectrum analyzer will only display the results from one channel of audio – if you want stereo, you’ll need two! And note that the strobe, reset and DCOUT pins on the MSGEQ7 are labelled with the connections to the cube PCB. Furthermore the pinouts for the MSGEQ7 don’t match the physical reality – here are the pinouts from the MSGEQ7 data sheet (.pdf):
The circuit itself will be quite small and fit on a small amount of stripboard or veroboard. There is plenty of room underneath the cube to fit the circuit if so desired:
With a few moments you should be able to trace out your circuit to match the board type you have, remember to double-check before soldering. You will also need to connect the audio in point after the 1000 pF capacitor to a source of audio, and also pass it through so you can connect powered speakers, headphones, etc.
One method of doing so would be to cut up a male-female audio extension lead, and connect the shield to the GND of the circuit, and the signal line to the audio input on the circuit. Or if you have the parts handy and some shielded cable, just make your own input and output leads:
Be sure to test for shorts between the signal and shield before soldering to the circuit board. When finished, you should have something neat that you can hide under the cube or elsewhere:
Double-check your soldering for shorts and your board plan, then fit to the cube along with the audio source and speakers (etc).
Arduino Sketch
The sketch has two main functions – the first is to capture the levels from the MSGEQ7 and put the values for each frequency band into an array, and the second function is to turn on LEDs that represent the level for each band. If you’ve been paying attention you may be wondering how we can represent seven frequency bands with a 4x4x4 LED cube. Simple – by rotating the cube 45 degrees you can see seven vertical columns of LEDs:
So when looking from the angle as shown above, you have seven vertical columns, each with four levels of LEDs. Thus the strength of each frequency can be broken down into four levels, and then the appropriate LEDs turned on.
After this is done for each band, all the LEDs are turned off and the process repeats. For the sake of simplicity I’ve used the cube’s Arduino library to activate the LEDs, which also makes the sketch easier to fathom. The first example sketch only uses one colour:
// Freetronics CUBE4: and MSGEQ7 spectrum analyser
// MSGEQ7 strobe on A4, reset on D5, signal into A0
#include "SPI.h"
#include "Cube.h"
Cube cube;
int res = 5; // reset pins on D5
int left[7]; // store band values in these arrays
int band;
void setup()
{
pinMode(res, OUTPUT); // reset
pinMode(A4, OUTPUT); // strobe
digitalWrite(res,LOW);
digitalWrite(A4,HIGH);
cube.begin(-1, 115200);
Serial.begin(9600);
}
void readMSGEQ7()
// Function to read 7 band equalizers
{
digitalWrite(res, HIGH);
digitalWrite(res, LOW);
for(band=0; band <7; band++)
{
digitalWrite(A4,LOW); // strobe pin on the shield - kicks the IC up to the next band
delayMicroseconds(30); //
left[band] = analogRead(0); // store band reading
digitalWrite(A4,HIGH);
}
}
void loop()
{
readMSGEQ7();
for (band = 0; band < 7; band++)
{
// div each band strength into four layers, each band then one of the odd diagonals
// band one ~ 63 Hz
if (left[0]>=768) {
cube.set(3,3,3, BLUE);
}
else
if (left[0]>=512) {
cube.set(3,3,2, BLUE);
}
else
if (left[0]>=256) {
cube.set(3,3,1, BLUE);
}
else
if (left[0]>=0) {
cube.set(3,3,0, BLUE);
}
// band two ~ 160 Hz
if (left[1]>=768)
{
cube.set(3,2,3, BLUE);
cube.set(2,3,3, BLUE);
}
else
if (left[1]>=512)
{
cube.set(3,2,2, BLUE);
cube.set(2,3,2, BLUE);
}
else
if (left[1]>=256)
{
cube.set(3,2,1, BLUE);
cube.set(2,3,1, BLUE);
}
else
if (left[1]>=0)
{
cube.set(3,2,0, BLUE);
cube.set(2,3,0, BLUE);
}
// band three ~ 400 Hz
if (left[2]>=768)
{
cube.set(3,1,3, BLUE);
cube.set(2,2,3, BLUE);
cube.set(1,3,3, BLUE);
}
else
if (left[2]>=512)
{
cube.set(3,1,2, BLUE);
cube.set(2,2,2, BLUE);
cube.set(1,3,2, BLUE);
}
else
if (left[2]>=256)
{
cube.set(3,1,1, BLUE);
cube.set(2,2,1, BLUE);
cube.set(1,3,1, BLUE);
}
else
if (left[2]>=0)
{
cube.set(3,1,0, BLUE);
cube.set(2,2,0, BLUE);
cube.set(1,3,0, BLUE);
}
// band four ~ 1 kHz
if (left[3]>=768)
{
cube.set(3,0,3, BLUE);
cube.set(2,1,3, BLUE);
cube.set(1,2,3, BLUE);
cube.set(0,3,3, BLUE);
}
else
if (left[3]>=512)
{
cube.set(3,0,2, BLUE);
cube.set(2,1,2, BLUE);
cube.set(1,2,2, BLUE);
cube.set(0,3,2, BLUE);
}
else
if (left[3]>=256)
{
cube.set(3,0,1, BLUE);
cube.set(2,1,1, BLUE);
cube.set(1,2,1, BLUE);
cube.set(0,3,1, BLUE);
}
else
if (left[3]>=0)
{
cube.set(3,0,0, BLUE);
cube.set(2,1,0, BLUE);
cube.set(1,2,0, BLUE);
cube.set(0,3,0, BLUE);
}
// band five ~ 2.5 kHz
if (left[4]>=768)
{
cube.set(2,0,3, BLUE);
cube.set(1,1,3, BLUE);
cube.set(0,2,3, BLUE);
}
else
if (left[4]>=512)
{
cube.set(2,0,2, BLUE);
cube.set(1,1,2, BLUE);
cube.set(0,2,2, BLUE);
}
else
if (left[4]>=256)
{
cube.set(2,0,1, BLUE);
cube.set(1,1,1, BLUE);
cube.set(0,2,1, BLUE);
}
else
if (left[4]>=0)
{
cube.set(2,0,0, BLUE);
cube.set(1,1,0, BLUE);
cube.set(0,2,0, BLUE);
}
// band six ~ 6.25 kHz
if (left[5]>=768)
{
cube.set(1,0,3, BLUE);
cube.set(0,1,3, BLUE);
}
else
if (left[5]>=512)
{
cube.set(1,0,2, BLUE);
cube.set(0,1,2, BLUE);
}
else
if (left[5]>=256)
{
cube.set(1,0,1, BLUE);
cube.set(0,1,1, BLUE);
}
else
if (left[5]>=0)
{
cube.set(1,0,0, BLUE);
cube.set(0,1,0, BLUE);
}
// band seven ~ 16 kHz
if (left[6]>=768)
{
cube.set(0,0,3, BLUE);
}
else
if (left[6]>=512)
{
cube.set(0,0,2, BLUE);
}
else
if (left[6]>=256)
{
cube.set(0,0,1, BLUE);
}
else
if (left[6]>=0)
{
cube.set(0,0,0, BLUE);
}
}
// now clear the CUBE, or if that's too slow - repeat the process but turn LEDs off
cube.all(BLACK);
}
… and a quick video demonstration:
For a second example, we’ve used various colours:
// Freetronics CUBE4: and MSGEQ7 spectrum analyser
// MSGEQ7 strobe on A4, reset on D5, signal into A0
// now in colour!
#include "SPI.h"
#include "Cube.h"
Cube cube;
int res = 5; // reset pins on D5
int left[7]; // store band values in these arrays
int band;
int additional=0;
void setup()
{
pinMode(res, OUTPUT); // reset
pinMode(A4, OUTPUT); // strobe
digitalWrite(res,LOW);
digitalWrite(A4,HIGH);
cube.begin(-1, 115200);
Serial.begin(9600);
}
void readMSGEQ7()
// Function to read 7 band equalizers
{
digitalWrite(res, HIGH);
digitalWrite(res, LOW);
for(band=0; band <7; band++)
{
digitalWrite(A4,LOW); // strobe pin on the shield - kicks the IC up to the next band
delayMicroseconds(30); //
left[band] = analogRead(0) + additional; // store band reading
digitalWrite(A4,HIGH);
}
}
void loop()
{
readMSGEQ7();
for (band = 0; band < 7; band++)
{
// div each band strength into four layers, each band then one of the odd diagonals
// band one ~ 63 Hz
if (left[0]>=768) {
cube.set(3,3,3, RED);
}
else
if (left[0]>=512) {
cube.set(3,3,2, YELLOW);
}
else
if (left[0]>=256) {
cube.set(3,3,1, YELLOW);
}
else
if (left[0]>=0) {
cube.set(3,3,0, BLUE);
}
// band two ~ 160 Hz
if (left[1]>=768)
{
cube.set(3,2,3, RED);
cube.set(2,3,3, RED);
}
else
if (left[1]>=512)
{
cube.set(3,2,2, YELLOW);
cube.set(2,3,2, YELLOW);
}
else
if (left[1]>=256)
{
cube.set(3,2,1, YELLOW);
cube.set(2,3,1, YELLOW);
}
else
if (left[1]>=0)
{
cube.set(3,2,0, BLUE);
cube.set(2,3,0, BLUE);
}
// band three ~ 400 Hz
if (left[2]>=768)
{
cube.set(3,1,3, RED);
cube.set(2,2,3, RED);
cube.set(1,3,3, RED);
}
else
if (left[2]>=512)
{
cube.set(3,1,2, YELLOW);
cube.set(2,2,2, YELLOW);
cube.set(1,3,2, YELLOW);
}
else
if (left[2]>=256)
{
cube.set(3,1,1, YELLOW);
cube.set(2,2,1, YELLOW);
cube.set(1,3,1, YELLOW);
}
else
if (left[2]>=0)
{
cube.set(3,1,0, BLUE);
cube.set(2,2,0, BLUE);
cube.set(1,3,0, BLUE);
}
// band four ~ 1 kHz
if (left[3]>=768)
{
cube.set(3,0,3, RED);
cube.set(2,1,3, RED);
cube.set(1,2,3, RED);
cube.set(0,3,3, RED);
}
else
if (left[3]>=512)
{
cube.set(3,0,2, YELLOW);
cube.set(2,1,2, YELLOW);
cube.set(1,2,2, YELLOW);
cube.set(0,3,2, YELLOW);
}
else
if (left[3]>=256)
{
cube.set(3,0,1, YELLOW);
cube.set(2,1,1, YELLOW);
cube.set(1,2,1, YELLOW);
cube.set(0,3,1, YELLOW);
}
else
if (left[3]>=0)
{
cube.set(3,0,0, BLUE);
cube.set(2,1,0, BLUE);
cube.set(1,2,0, BLUE);
cube.set(0,3,0, BLUE);
}
// band five ~ 2.5 kHz
if (left[4]>=768)
{
cube.set(2,0,3, RED);
cube.set(1,1,3, RED);
cube.set(0,2,3, RED);
}
else
if (left[4]>=512)
{
cube.set(2,0,2, YELLOW);
cube.set(1,1,2, YELLOW);
cube.set(0,2,2, YELLOW);
}
else
if (left[4]>=256)
{
cube.set(2,0,1, YELLOW);
cube.set(1,1,1, YELLOW);
cube.set(0,2,1, YELLOW);
}
else
if (left[4]>=0)
{
cube.set(2,0,0, BLUE);
cube.set(1,1,0, BLUE);
cube.set(0,2,0, BLUE);
}
// band six ~ 6.25 kHz
if (left[5]>=768)
{
cube.set(1,0,3, RED);
cube.set(0,1,3, RED);
}
else
if (left[5]>=512)
{
cube.set(1,0,2, YELLOW);
cube.set(0,1,2, YELLOW);
}
else
if (left[5]>=256)
{
cube.set(1,0,1, YELLOW);
cube.set(0,1,1, YELLOW);
}
else
if (left[5]>=0)
{
cube.set(1,0,0, BLUE);
cube.set(0,1,0, BLUE);
}
// band seven ~ 16 kHz
if (left[6]>=768)
{
cube.set(0,0,3, RED);
}
else
if (left[6]>=512)
{
cube.set(0,0,2, YELLOW);
}
else
if (left[6]>=256)
{
cube.set(0,0,1, YELLOW);
}
else
if (left[6]>=0)
{
cube.set(0,0,0, BLUE);
}
}
// now clear the CUBE, or if that's too slow - repeat the process but turn LEDs off
cube.all(BLACK);
}
… and the second video demonstration:
A little bit of noise comes through into the spectrum analyzer, most likely due to the fact that the entire thing is unshielded. The previous prototype used the Arduino shield from the tutorial which didn’t have this problem, so if you’re keen perhaps make your own custom PCB for this project.
Conclusion
Well that was something different and I hope you enjoyed it, and can find use for the circuit. That MSGEQ7 is a handy IC and with some imagination you can create a variety of musically-influenced displays. And while you’re here – are you interested in learning more about Arduino? Then order my new book “Arduino Workshop” from No Starch Press.
In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitter, Google+, subscribe for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other – and we can all learn something.
In this review we examine the Pocket Oscillator Kit from Altronics, based on an design from (the now defunct) February and March 1989 editions of Electronics Australia magazine. The purpose of this oscillator is to give you a high quality, portable square or sine wave generator that can be used to test audio equipment, speaker response, fool about with oscilloscopes (!), and so on. The prototype basic specifications are as follows:
Frequency range: 41~1082 Hz and 735 Hz~18.1 kHz
Output: 1.27V RMS sine, 1.45V peak square
Load: 1.0V RMS sine into 330 Ω
Distortion: 0.16% THD at 1 kHz
Assembly
The kit is packaged in typical form, without any surprises:
In the usual Altronics fashion, the instructions are accompanied with a neat “electronics reference sheet” which covers many useful topics such as resistor colour codes, various formulae, PCB track widths, pinouts and more. The kit instructions are based on the original magazine article and include a small addendum which isn’t any problem.
Unlike some kits, everything is included to create a finished product (except for the IC socket):
… including a nice enclosure which has the control instructions screen-printed on the lid…
However at this point I think the definition of a “pocket” is the same used by Sir Clive Sinclair when he had those pocket televisions. At this time I won’t use the enclosure as my drill press is in storage, however look forward to fitting the kit within at a later point. The PCB has a neat solder mask and silk screen:
Assembly was pretty straight forward, the original design has tried to minimise PCB real-estate, so all the resistors are mounted vertically. The signal diodes take this a step further – each pair needs to be soldered together:
… then the pair is also mounted vertically:
However it all works in the end. The rest of the circuit went together well, and we used our own IC socket for the opamp:
From this point you need to wire up the power, switches and potentiometers:
… and consider mounting the whole lot in the enclosure (or before assembly!):
However as mentioned earlier, I just went for the open octopus method for time being:
How it works
The oscillator is based around the Texas Instruments TL064 opamp, and due to copyright I can’t give you the schematic. For complete details on the oscillator, either purchase the kit or locate the February and March 1989 edition of Electronics Australia magazine. However the waveforms from the oscillator looked good (as far as they can on a DSO):
Conclusion
The oscillator works well, however the PCB layout could have been a little lot easier on the end-user. It’s time for a redesign, possibly put all the contacts for external switches around the perimeter – and allow space for the diodes to lay normally. Nevertheless – this is a neat kit, and still quite popular after all these years. For the price you get a few hours of kit fun and a useful piece of test equipment. So if you’re into audio or experimenting, check it out. Full-sized images are available on flickr.
And while you’re here – are you interested in Arduino? Check out my new book “Arduino Workshop” from No Starch Press – also shortly available from Altronics.
In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitter, Google+, subscribe for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other – and we can all learn something.
[Note - kit purchased without notifying the supplier]
It’s no secret that I enjoy kit reviews – it’s always interesting to see how well a kit goes together, along with the quality of parts, documentation and so on. But what about kits from the past? And not 2003. Recently a very rare opportunity to purchase a sealed Sinclair Radionics Cambridge calculator kit appeared on ebay – so it was ordered rapidly and duly delivered to the office. And thus the subject of this review.
You may be familiar with the Sinclair name – Sir Clive Sinclair introduced many innovative and interesting products to the UK and world markets in his own style. Some were a raging success, such as the ZX-series home computers – and some were not. However in 1973 Sinclair introduced a range of calculators, starting with the “Cambridge”. It’s a simple four-function calculator with an LED numeric display and a somewhat dodgy reputation.
The design evolved rapidly and at the Mark III stage it was sold assembled and as a kit. At the time handheld calculators were quite expensive, so the opportunity to save money and get one in kit form would have been quite appealing to the enthusiast – in January 1974 the kit retailed in the UK for 24.95 (+ VAT):
Assembly
Putting the Cambridge together required a balance of healthy paranoia, patience and woodworker mentality (measure twice – cut once). There wouldn’t be any second chances, or quick runs down to Altronics for a replacement part (well … there was one) so care needed to be taken. If you’re curious about the details, I’ve uploaded 82 full-resolution images from the build, including both instruction manuals and schematic onto flickr. Now to get started.
The kit arrives in a neat, retail-orientated package:
… with the components on one side of the foam:
… and the other side held he assembly guide (underneath which was a very short length of solder and the carrying case):
At this point I was starting to have doubts, and thought it would be better off in storage. But what fun would that be? So out with the knife and the shrink-wrap was gone, revealing the smell of 1974 electronics. Next to whip out the instructions and get started:
They are incredibly detailed, and allow for two variations of enclosure and also offer tips on good construction – as well as the schematic, BOM and so on. Like any kit it’s wise to take stock of the components, which gave us the PCB:
… the passives, diodes and transistor – and some solder wick:
At this point it turned out the all but one of the resistors were anywhere near the specified values in the instructions, and I wasn’t going to trust those electrolytic capacitors after 39 years. The replacement parts were in stock – including the original 1n914 diode that was missing from the kit. Thanks Clive. There was also a coil of unknown value:
… and the ICs, which included the brains of the operation – a General Instrument Microelectronics CZL-550:
… and an ITT 7105N:
… a bag of battery clips, buttons and adhesive-backed foam (which deteriorated nicely):
At this point it was time to fire up the Hakko and start soldering, not before giving the PCB a good hit with the Servisol cleaner spray. I was worried about the tracks lifting while soldering due to heat and old-age, however the PCB held up quite well. The first step is to solder in the clips that hold (just) four AAA cells:
… then the resistors and diodes:
… followed by the transistor, ITT IC, ceramic capacitor and coil:
Uh-oh – that ceramic went in the wrong hole. One leg was soldered where the coil was to sit. Without wanting to damage the PCB, de-soldering it was a slow, slow process. Then of course I didn’t have a ) 3.3nF in stock, so a quick spin to Altronics solved that problem (I bought 50) – one of which finally went in:
The transistor was also a bit of a puzzle, I hadn’t seen that enclosure type and the manual wasn’t much help, so the semiconductor analyser tester solved that problem:
The next step was to fit the display, which is wedged in the large gap at the top of the PCB. The tracks on the PCB are supposed to meet the display, however time had affected the tracks on the display module, so I soldered small wire links across the gaps:
Following the display were the two (new) electrolytics:
And now to the main IC. There wasn’t any second chances with this, and after some very gently pin-bending it dropped in nicely:
After a short break it was time to assemble the keypad, which went smoothly. After cleaning all the foam dust off the buttons, they dropped in to their frame which in turn dropped into the enclosure, followed by the keypad layers:
You can also see in the display window and shroud have been fitted. From here the PCB is inserted:
… and a sticker from years gone by, as well as the metal clip over the bottom of the power switch. At this point a quick test with four AAA cells showed signs of life on the display, so the rear enclosure could be fitted:
Now for the battery and final cover, and it’s ready to go!
The digits are quite sharp, but very small – and set back from the window. This makes photography quite difficult. At the time if your calculator didn’t work, you could send it off to Sinclair and they’d repair or possibly replace it for you:
Using the Cambridge
Well it works, so you have a calculator which is genuinely useful. However the Cambridge has a few quirks, which are attributed to the basic functions of the main IC. For example, when entering numbers the screen is filled with leading zeros until you select a function, however by using the manual you can complete complex work including square roots, percentages, loan repayments and much more.
Furthermore the Cambridge is quite the silent achiever, you can work with numbers as small as 1x10E-20 and up to 9.9999999E79. You simply enter the numbers in decimal form (e.g. 0.000000000123) … even though the display won’t show all the digits, they’re being stored in a register. To then extract the result, you continually multiply or divide by ten (making note of how many times you do that) until the digits appear on the screen. It sounds nuts today – but in 1974 it would have been a cheap way of avoiding a more expensive calculator. In the following video you can see th Cambridge in action, plus the results of dividing by zero:
More about Sinclair
The following video is a BBC dramatisation of the rise of the home computer in the UK market, and the competition between Sir Clive Sinclair (Sinclair) and Adam Curry (Acorn Computers) – which is quite entertaining:
You can find out more about the history of Sir Clive Sinclair here, and the calculator range here. If anyone can connect us with a Science of Cambridge MK14 computer, contact us.
Conclusion
From a 1974 perspective, that would have been a great kit to make, with some love and care it would have been successful. By today’s standards it was quite average – however you can’t really judge it from a 2013 perspective. Nevertheless, kudos to Sir Clive Sinclair for his efforts in knocking out a useful product as a kit. If you’re a collector, and see a sealed unit on ebay or elsewhere, give it a whirl. Just take your time, “think before doing”, and replace as many of the components as possible. I’ve put all the images in full resolution up on flickr, so you can follow along in more detail.
And while you’re here – are you interested in Arduino? Check out my new book “Arduino Workshop” from No Starch Press.
In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitter, Google+, subscribe for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other – and we can all learn something.
The subject of our latest kit review is the “Epoch Clock” from Maniacal Labs, a new organisation started by three young lads with some interesting ideas. Regular readers will know we love a clock – so when the opportunity came to review this one, we couldn’t say no.
At this point you may be thinking “what is Epoch time anyway?”. Good question! It is the number of seconds elapsed since the first of January, 1970 (UTC) – and used by Unix-based computers as the start of their time universe. (For more on the theory of Epoch time, check out Wikipedia). For example - 1379226077 Epoch time is Sun, 15 Sep 2013 06:21:17 GMT. That’s a lot of seconds. If you’re curious, you can do more calculations with the EpochTime website.
Moving forward, this clock kit will show Epoch time in full 32-bit binary glory, using a DS1307 real-time clock IC (with backup battery) and is controlled with an ATmega328P-PU – so you can modify the code easily with the Arduino IDE or WinAVR (etc).
Assembly
The creators have spent a lot of time on not only the packaging and out-of-box-experience, but also the documentation and setup guide – so as long as you’re fine with simple through-hole soldering the kit will not present any challenges. The kit arrives in a sturdy box:
… with well packaged components. Everything is included for the finished product, as well as IC sockets, the RTC backup battery and a USB cable so you can power the clock from a USB hub:
The PCB is a good thickness, and has a clear silk-screen and solder mask:
Construction is simple, just follow the step-by-step instructions. Starting with the USB socket for power:
… then the resistors:
… the LEDs:
… all 32 of them. Note that the LEDs don’t sit flush with the PCB, so a little effort is required to keep them aligned:
Then the rest of the components just fit as expected. I’ve also added the included header pins for an FTDI programming cable and ICSP to keep my options open:
Then simply fit the battery, insert the ICs and you’re done:
Using the clock
The microcontroller is pre-programmed, so you can use the clock straight away. You will however need to set the time first. To make this incredibly easy, there is a special web page that displays the current time and Epoch time, which steps you through the process of setting the time using the buttons.
Or with some code available on the kit github page and a programming cable, you can automatically sync it to the clock. Once setup, the battery will keep the current time in the RTC nicely. The clock is powered by 5V, which is easily supplied with the included USB cable, or you can always hack in your own feed.
So what does Epoch time in 32-bit binary look like? Here’s a short video of the clock in action:
Reading the time requires converting the binary number displayed with the LEDs back to a decimal number – which is of course the Epoch count of seconds since 1/1/1970. Math teachers will love this thing.
But wait, there’s more!
If you get tired of the blinking, there’s a test function which is enabled by holding down both buttons for a second, which turns the Epoch Clock into a nifty Larson Scanner:
To create your own sketches or examine the design files in more detail, it’s all on the clock github page. From a hardware perspective you have an ATmega328P-PU development board with a DS1307 battery-backed real-time clock – with 32 LEDs. So you could also create your own kind of clock or other multi-LED blinking project without too much effort. Review the EpochClockSchematic (.pdf) to examine this in more detail.
Conclusion
I really enjoyed this kit – it was easy to assemble, I learned something new and frankly the blinking LEDs can be quite soothing. The clock would make a great for a conversation-starter in the office, or would make an ideal gift for any Sheldon Cooper-types you might be associated with. Or have competitions to see who can convert the display to normal time. After shots.
Nevertheless it’s a fun and imaginative piece of kit, fully Open Hardware-compliant – and if you’ve made it this far – get some and have fun. Full-sized images are on flickr. Interested in Arduino? Check out my new book “Arduino Workshop” from No Starch Press.
In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitter, Google+, subscribe for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other – and we can all learn something.
[Note - The kit reviewed was a promotional consideration from Maniacal Labs]
Time for another kit review, and in this instalment we’ve received some LED matrix modules and a matching Arduino-compatible controller board from friedcircuits.us. Behind the name is William Garrido – who some of you may know as “mobile will” from following his blog. Over time William has created a range of small and useful products, which are now available on the tindie online store.
The system comprises of two modules. The first is a small Arduino-compatible board with an ATmega328P microcontroller – the LED matrix master. It’s quite small and is designed to be the start of a chain of matching LED matrix link boards. Each of these holds an 8×8 LED matrix and is controlled by the AS1107 LED driver IC. This is a direct replacement IC for the popular MAX7219, works exactly the same and is a great find instead of using knock-off MAX7219s. You can chain up to 8 matrix modules from the one controller. We received a matrix master and two matrix link boards to examine, which arrived in solid packaging a fun Tindie sticker:
Assembly
All the surface-mount soldering is done in advance, leaving you with some simple through-hole soldering for the LED matrix and the connectors between each module. The PCBs are clearly labelled with the silk screen and have mounting holes for permanent installations:
So after a few minutes of soldering it’s time to get the blinking on:
You may have noticed by now that the master board doesn’t have a USB socket, so you’ll need a 5V FTDI cable or a USBasp programmer to upload your Arduino sketches or AVR .hex file to get things moving.
Controlling a matrix or more
As the system is basically an Arduino-compatible with one or more MAX7219-compatible modules you can find all sorts of example sketches to experiment with. If you haven’t used a MAX7219/AS1107 before there are a couple of starting points including the Arduino library and another random tutorial. Using an example sketch on the Arduino forum by member “danigom“, and after checking the data, clock and load pins it was ready to go. Here’s the sketch for your consideration:
/* Program is currently hard coded to drive 4x MAX7219 chips
though altering code to drive upto 7 chips is trivial
Orginal sketch by Arduino forum member "danigom"
http://forum.arduino.cc/index.php?action=profile;u=188950
*/
//We always have to include the libraries
#include <avr/pgmspace.h>
#include <LedControl.h>
// *CONSTANTS
const int DIN = 12; //DataIn pin (18)
const int CLK = 11; //Clock pin (17)
const int LOAD = 10; //Load pin (16)
const int numDevices = 2; //Number of MAX7219 LED Driver Chips (1-8)
const long scrollDelay = 70;
prog_uchar font5x7 [] PROGMEM = { //Numeric Font Matrix (Arranged as 7x font data + 1x kerning data)
B00000000, //Space (Char 0x20)
B00000000,
B00000000,
B00000000,
B00000000,
B00000000,
B00000000,
6,
B10000000, //!
B10000000,
B10000000,
B10000000,
B00000000,
B00000000,
B10000000,
2,
B10100000, //"
B10100000,
B10100000,
B00000000,
B00000000,
B00000000,
B00000000,
4,
B01010000, //#
B01010000,
B11111000,
B01010000,
B11111000,
B01010000,
B01010000,
6,
B00100000, //$
B01111000,
B10100000,
B01110000,
B00101000,
B11110000,
B00100000,
6,
B11000000, //%
B11001000,
B00010000,
B00100000,
B01000000,
B10011000,
B00011000,
6,
B01100000, //&
B10010000,
B10100000,
B01000000,
B10101000,
B10010000,
B01101000,
6,
B11000000, //'
B01000000,
B10000000,
B00000000,
B00000000,
B00000000,
B00000000,
3,
B00100000, //(
B01000000,
B10000000,
B10000000,
B10000000,
B01000000,
B00100000,
4,
B10000000, //)
B01000000,
B00100000,
B00100000,
B00100000,
B01000000,
B10000000,
4,
B00000000, //*
B00100000,
B10101000,
B01110000,
B10101000,
B00100000,
B00000000,
6,
B00000000, //+
B00100000,
B00100000,
B11111000,
B00100000,
B00100000,
B00000000,
6,
B00000000, //,
B00000000,
B00000000,
B00000000,
B11000000,
B01000000,
B10000000,
3,
B00000000, //-
B00000000,
B11111000,
B00000000,
B00000000,
B00000000,
B00000000,
6,
B00000000, //.
B00000000,
B00000000,
B00000000,
B00000000,
B11000000,
B11000000,
3,
B00000000, ///
B00001000,
B00010000,
B00100000,
B01000000,
B10000000,
B00000000,
6,
B01110000, //0
B10001000,
B10011000,
B10101000,
B11001000,
B10001000,
B01110000,
6,
B01000000, //1
B11000000,
B01000000,
B01000000,
B01000000,
B01000000,
B11100000,
4,
B01110000, //2
B10001000,
B00001000,
B00010000,
B00100000,
B01000000,
B11111000,
6,
B11111000, //3
B00010000,
B00100000,
B00010000,
B00001000,
B10001000,
B01110000,
6,
B00010000, //4
B00110000,
B01010000,
B10010000,
B11111000,
B00010000,
B00010000,
6,
B11111000, //5
B10000000,
B11110000,
B00001000,
B00001000,
B10001000,
B01110000,
6,
B00110000, //6
B01000000,
B10000000,
B11110000,
B10001000,
B10001000,
B01110000,
6,
B11111000, //7
B10001000,
B00001000,
B00010000,
B00100000,
B00100000,
B00100000,
6,
B01110000, //8
B10001000,
B10001000,
B01110000,
B10001000,
B10001000,
B01110000,
6,
B01110000, //9
B10001000,
B10001000,
B01111000,
B00001000,
B00010000,
B01100000,
6,
B00000000, //:
B11000000,
B11000000,
B00000000,
B11000000,
B11000000,
B00000000,
3,
B00000000, //;
B11000000,
B11000000,
B00000000,
B11000000,
B01000000,
B10000000,
3,
B00010000, //<
B00100000,
B01000000,
B10000000,
B01000000,
B00100000,
B00010000,
5,
B00000000, //=
B00000000,
B11111000,
B00000000,
B11111000,
B00000000,
B00000000,
6,
B10000000, //>
B01000000,
B00100000,
B00010000,
B00100000,
B01000000,
B10000000,
5,
B01110000, //?
B10001000,
B00001000,
B00010000,
B00100000,
B00000000,
B00100000,
6,
B01110000, //@
B10001000,
B00001000,
B01101000,
B10101000,
B10101000,
B01110000,
6,
B01110000, //A
B10001000,
B10001000,
B10001000,
B11111000,
B10001000,
B10001000,
6,
B11110000, //B
B10001000,
B10001000,
B11110000,
B10001000,
B10001000,
B11110000,
6,
B01110000, //C
B10001000,
B10000000,
B10000000,
B10000000,
B10001000,
B01110000,
6,
B11100000, //D
B10010000,
B10001000,
B10001000,
B10001000,
B10010000,
B11100000,
6,
B11111000, //E
B10000000,
B10000000,
B11110000,
B10000000,
B10000000,
B11111000,
6,
B11111000, //F
B10000000,
B10000000,
B11110000,
B10000000,
B10000000,
B10000000,
6,
B01110000, //G
B10001000,
B10000000,
B10111000,
B10001000,
B10001000,
B01111000,
6,
B10001000, //H
B10001000,
B10001000,
B11111000,
B10001000,
B10001000,
B10001000,
6,
B11100000, //I
B01000000,
B01000000,
B01000000,
B01000000,
B01000000,
B11100000,
4,
B00111000, //J
B00010000,
B00010000,
B00010000,
B00010000,
B10010000,
B01100000,
6,
B10001000, //K
B10010000,
B10100000,
B11000000,
B10100000,
B10010000,
B10001000,
6,
B10000000, //L
B10000000,
B10000000,
B10000000,
B10000000,
B10000000,
B11111000,
6,
B10001000, //M
B11011000,
B10101000,
B10101000,
B10001000,
B10001000,
B10001000,
6,
B10001000, //N
B10001000,
B11001000,
B10101000,
B10011000,
B10001000,
B10001000,
6,
B01110000, //O
B10001000,
B10001000,
B10001000,
B10001000,
B10001000,
B01110000,
6,
B11110000, //P
B10001000,
B10001000,
B11110000,
B10000000,
B10000000,
B10000000,
6,
B01110000, //Q
B10001000,
B10001000,
B10001000,
B10101000,
B10010000,
B01101000,
6,
B11110000, //R
B10001000,
B10001000,
B11110000,
B10100000,
B10010000,
B10001000,
6,
B01111000, //S
B10000000,
B10000000,
B01110000,
B00001000,
B00001000,
B11110000,
6,
B11111000, //T
B00100000,
B00100000,
B00100000,
B00100000,
B00100000,
B00100000,
6,
B10001000, //U
B10001000,
B10001000,
B10001000,
B10001000,
B10001000,
B01110000,
6,
B10001000, //V
B10001000,
B10001000,
B10001000,
B10001000,
B01010000,
B00100000,
6,
B10001000, //W
B10001000,
B10001000,
B10101000,
B10101000,
B10101000,
B01010000,
6,
B10001000, //X
B10001000,
B01010000,
B00100000,
B01010000,
B10001000,
B10001000,
6,
B10001000, //Y
B10001000,
B10001000,
B01010000,
B00100000,
B00100000,
B00100000,
6,
B11111000, //Z
B00001000,
B00010000,
B00100000,
B01000000,
B10000000,
B11111000,
6,
B11100000, //[
B10000000,
B10000000,
B10000000,
B10000000,
B10000000,
B11100000,
4,
B00000000, //(Backward Slash)
B10000000,
B01000000,
B00100000,
B00010000,
B00001000,
B00000000,
6,
B11100000, //]
B00100000,
B00100000,
B00100000,
B00100000,
B00100000,
B11100000,
4,
B00100000, //^
B01010000,
B10001000,
B00000000,
B00000000,
B00000000,
B00000000,
6,
B00000000, //_
B00000000,
B00000000,
B00000000,
B00000000,
B00000000,
B11111000,
6,
B10000000, //`
B01000000,
B00100000,
B00000000,
B00000000,
B00000000,
B00000000,
4,
B00000000, //a
B00000000,
B01110000,
B00001000,
B01111000,
B10001000,
B01111000,
6,
B10000000, //b
B10000000,
B10110000,
B11001000,
B10001000,
B10001000,
B11110000,
6,
B00000000, //c
B00000000,
B01110000,
B10001000,
B10000000,
B10001000,
B01110000,
6,
B00001000, //d
B00001000,
B01101000,
B10011000,
B10001000,
B10001000,
B01111000,
6,
B00000000, //e
B00000000,
B01110000,
B10001000,
B11111000,
B10000000,
B01110000,
6,
B00110000, //f
B01001000,
B01000000,
B11100000,
B01000000,
B01000000,
B01000000,
6,
B00000000, //g
B01111000,
B10001000,
B10001000,
B01111000,
B00001000,
B01110000,
6,
B10000000, //h
B10000000,
B10110000,
B11001000,
B10001000,
B10001000,
B10001000,
6,
B01000000, //i
B00000000,
B11000000,
B01000000,
B01000000,
B01000000,
B11100000,
4,
B00010000, //j
B00000000,
B00110000,
B00010000,
B00010000,
B10010000,
B01100000,
5,
B10000000, //k
B10000000,
B10010000,
B10100000,
B11000000,
B10100000,
B10010000,
5,
B11000000, //l
B01000000,
B01000000,
B01000000,
B01000000,
B01000000,
B11100000,
4,
B00000000, //m
B00000000,
B11010000,
B10101000,
B10101000,
B10001000,
B10001000,
6,
B00000000, //n
B00000000,
B10110000,
B11001000,
B10001000,
B10001000,
B10001000,
6,
B00000000, //o
B00000000,
B01110000,
B10001000,
B10001000,
B10001000,
B01110000,
6,
B00000000, //p
B00000000,
B11110000,
B10001000,
B11110000,
B10000000,
B10000000,
6,
B00000000, //q
B00000000,
B01101000,
B10011000,
B01111000,
B00001000,
B00001000,
6,
B00000000, //r
B00000000,
B10110000,
B11001000,
B10000000,
B10000000,
B10000000,
6,
B00000000, //s
B00000000,
B01110000,
B10000000,
B01110000,
B00001000,
B11110000,
6,
B01000000, //t
B01000000,
B11100000,
B01000000,
B01000000,
B01001000,
B00110000,
6,
B00000000, //u
B00000000,
B10001000,
B10001000,
B10001000,
B10011000,
B01101000,
6,
B00000000, //v
B00000000,
B10001000,
B10001000,
B10001000,
B01010000,
B00100000,
6,
B00000000, //w
B00000000,
B10001000,
B10101000,
B10101000,
B10101000,
B01010000,
6,
B00000000, //x
B00000000,
B10001000,
B01010000,
B00100000,
B01010000,
B10001000,
6,
B00000000, //y
B00000000,
B10001000,
B10001000,
B01111000,
B00001000,
B01110000,
6,
B00000000, //z
B00000000,
B11111000,
B00010000,
B00100000,
B01000000,
B11111000,
6,
B00100000, //{
B01000000,
B01000000,
B10000000,
B01000000,
B01000000,
B00100000,
4,
B10000000, //|
B10000000,
B10000000,
B10000000,
B10000000,
B10000000,
B10000000,
2,
B10000000, //}
B01000000,
B01000000,
B00100000,
B01000000,
B01000000,
B10000000,
4,
B00000000, //~
B00000000,
B00000000,
B01101000,
B10010000,
B00000000,
B00000000,
6,
B01100000, // (Char 0x7F)
B10010000,
B10010000,
B01100000,
B00000000,
B00000000,
B00000000,
5
};
prog_uchar scrollText[] PROGMEM ={
" THE QUICK BROWN FOX JUMPED OVER THE LAZY DOG 1234567890 the quick brown fox jumped over the lazy dog \0"};
// * GLOBAL VARIABLES
unsigned long bufferLong [14] = {0}; //Buffer for scrolling text
LedControl lc=LedControl(DIN,CLK,LOAD,numDevices);
void setup(){
for (int x=0; x<numDevices; x++){
lc.shutdown(x,false); //The MAX72XX is in power-saving mode on startup
lc.setIntensity(x,8); // Set the brightness to default value
lc.clearDisplay(x); // and clear the display
}
}
void loop(){
scrollMessage(scrollText);
scrollFont();
}
void scrollFont() {
for (int counter=0x20;counter<0x80;counter++){
loadBufferLong(counter);
delay(500);
}
}
// Scroll Message
void scrollMessage(prog_uchar * messageString) {
int counter = 0;
int myChar=0;
do {
// read back a char
myChar = pgm_read_byte_near(messageString + counter);
if (myChar != 0){
loadBufferLong(myChar);
}
counter++;
}
while (myChar != 0);
}
// Load character into scroll buffer
void loadBufferLong(int ascii){
if (ascii >= 0x20 && ascii <=0x7f){
for (int a=0;a<7;a++){ // Loop 7 times for a 5x7 font
unsigned long c = pgm_read_byte_near(font5x7 + ((ascii - 0x20) * 8) + a); // Index into character table to get row data
unsigned long x = bufferLong [a*2]; // Load current scroll buffer
x = x | c; // OR the new character onto end of current
bufferLong [a*2] = x; // Store in buffer
}
byte count = pgm_read_byte_near(font5x7 +((ascii - 0x20) * 8) + 7); // Index into character table for kerning data
for (byte x=0; x<count;x++){
rotateBufferLong();
printBufferLong();
delay(scrollDelay);
}
}
}
// Rotate the buffer
void rotateBufferLong(){
for (int a=0;a<7;a++){ // Loop 7 times for a 5x7 font
unsigned long x = bufferLong [a*2]; // Get low buffer entry
byte b = bitRead(x,31); // Copy high order bit that gets lost in rotation
x = x<<1; // Rotate left one bit
bufferLong [a*2] = x; // Store new low buffer
x = bufferLong [a*2+1]; // Get high buffer entry
x = x<<1; // Rotate left one bit
bitWrite(x,0,b); // Store saved bit
bufferLong [a*2+1] = x; // Store new high buffer
}
}
// Display Buffer on LED matrix
void printBufferLong(){
for (int a=0;a<7;a++){ // Loop 7 times for a 5x7 font
unsigned long x = bufferLong [a*2+1]; // Get high buffer entry
byte y = x; // Mask off first character
lc.setRow(3,a,y); // Send row to relevent MAX7219 chip
x = bufferLong [a*2]; // Get low buffer entry
y = (x>>24); // Mask off second character
lc.setRow(2,a,y); // Send row to relevent MAX7219 chip
y = (x>>16); // Mask off third character
lc.setRow(1,a,y); // Send row to relevent MAX7219 chip
y = (x>>8); // Mask off forth character
lc.setRow(0,a,y); // Send row to relevent MAX7219 chip
}
}
In the following video you can see the sketch in action with two and one matrix modules:
Where to from here?
The matrix modules can find a wide range of uses, from simple fun and scrolling text to various LED matrix games, status displays and more. They also work well with the XOBXOB IoT USB-connected example. The design files are available for perusal on the friedcircuits github page. And don’t forget the matrix master board in itself is a tiny Arduino-compatible – with the full eight ADCs and digital I/O pins available. Thus you can embed this in another project if so desired.
Conclusion
The LED matrix modules are simple to use and work well together. Plus the matrix master board makes for a neat little Arduino-compatible as well. For more information and to order, visit the friedcircuits.us website. Full-sized images are on flickr. And if you made it this far – check out my new book “Arduino Workshop” from No Starch Press.
In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitter, Google+, subscribe for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other – and we can all learn something.
[Note - kits reviewed were a promotional consideration from friedcircuits]
Every month Australian electronics magazine Silicon Chip publishes a few projects, and in this kit review we’ll look at an older but still current example from August 2004 – the 3-state Logic Probe Kit (Mk II). This is an inexpensive piece of test equipment that’s useful when checking digital logic states and as a kit, great for beginners. Avid readers of my kit reviews may remember the SMD version we examined in June… well it wasn’t that much of a success due to the size of the parts. However this through-hole version has been quite successful, so keep reading to find out more
Assembly
The kit is packaged in typical form, without any surprises:
In typical Altronics fashion, an updated assembly guide is provided along with a general reference to common electronics topics:
All the required parts are included – except for a 14-pin IC socket and two CR2016 batteries.
The PCB makes soldering easy with the silk-screen and solder mask:
However the resistor numbering is a bit out of whack, a few R-numbers are skipped. So before soldering, measure and line up all the resistors in numbered order – doing so will reduce the chance of fitting them in the wrong spot.
When it comes time to solder the power switch on the end, it’s necessary to clip off two tabs – one at each end of the switch. However this isn’t a problem:
Soldering in the rest of the components wasn’t any effort at all, they’ve been spaced around the PCB nicely:
Once they’re in, it’s time to insert the pins that hold the probe (shown on the left below):
A full-sized probe is included with the kit, which you cut down with a hacksaw to allow it to fit on the end of the PCB. Then solder a short wire from the tip’s collar and run it through the body as such:
At this point, it’s time to break out the butane torch:
… with which you melt down the heatshrink over the tip, then fit it to the PCB and solder the probe wire:
At this point it’s wise to fit the batteries and test that the probe works, as the next stage is to heatshrink the entire circuit to the left of the LEDs:
Use
Using the probe is incredibly simple – however note that it’s designed for working with 5V logic. If you need to use higher voltages the probe can be assembled with slightly different circuit to take care of that eventuality. Moving forward simply clip the lead to GND on the circuit under test, then probe where you want to measure. The LEDs will indicate either HIGH, LOW or the PULSE LED will light when a fault is apparent, or other need for further research into the circuit. Here’s a quick demonstration probing a signal from an Arduino board:
Conclusion
This through-hole version of the logic probe kit was much easier to construct than the SMD version, and worked first time. A logic probe itself is a very useful tool to have and I highly recommend this kit for the beginner who enjoys projects and is growing their stable of test equipment on a budget. You can find the kit at Altronics and their distributors.
Full-sized images available on flickr. And if you made it this far – check out my new book “Arduino Workshop” from No Starch Press.
In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitter, Google+, subscribe for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other – and we can all learn something.
[Note - kit purchased without notifying the supplier]
From 1981, Australian electrical engineer Colin Mitchell started publishing his home-grown electronics magazine “Talking Electronics”. His goal was to get people interested and learning about electronics, and more so with a focus on digital electronics. It was (and still is) a lofty goal – in which he succeeded. From a couple of rooms in his home the magazine flourished, and many projects described within were sold as kits. You could find the books and kits in retail outlets such as Dick Smith Electronics, and for a short while there was a TE store in Moorabbin (Victoria). Colin and the team’s style of writing was easy to read and very understandable – but don’t take my word for it, you can download the magazines from his website (they’re near the bottom of the left column). Dave Jones recently interviewed Colin, and you can watch those for much more background information.
Over fifteen issues you could learn about blinking LEDs all the way to making your own expandable Z80 board computer, and some of the kits may still be available. Colin also published a series of tutorial books on electronics, and also single-magazine projects. And thus the subjects of our review … we came across the first of these single-issue projects from 1981 – the Mini Frequency Counter (then afterwards we have another kit):
How great is that? The PCB comes with the magazine. This is what set TE apart from the rest, and helped people learn by actually making it easy to build what was described in the magazine instead of just reading about it. For 1981 the PCB was quite good – they were silk-screened which was quite rare at the time:
And if you weren’t quite ready, the magazine also included details of a square-wave oscillator to make and a 52-page short course in digital electronics. However back to the kit…
Assembly
The kit uses common parts and I hoard CMOS ICs so building wasn’t a problem. This (original) version of the kit used LEDs instead of 7-segment displays (which were expensive at the time) so there was plenty of careful soldering to do:
And after a while the counter started to come together. I used IC sockets just in case:
The rest was straight-forward, and before long 9 V was supplied, and we found success:
To be honest progress floundered for about an hour at this point – the display wouldn’t budge off zero. After checking the multi-vibrator output, calibrating the RC circuits and finally tracing out the circuit with a continuity tester, it turned out one of the links just wasn’t soldered in far enough – and the IC socket for the 4047 was broken So a new link and directly fitting the 4047 fixed it. You live and learn.
Operation
So – we now have a frequency counter that’s good for 100 Hz to the megahertz range, with a minimum of parts. Younger, non-microcontroller people may wonder how that is possible – so here’s the schematic:
The counter works by using a multi-vibrator using a CD4047 to generate a square-wave at 50, 500 and 5 kHz, and the three trimpots are adjusted to calibrate the output. The incoming pulses to measure are fed to the 4026 decade counter/divider ICs. Three of these operate in tandem and each divide the incoming count by ten – and display or reset by the alternating signal from the 4047. However for larger frequencies (above 900 Hz) you need to change the frequency fed to the display circuit in order to display the higher (left-most) digits of the result. A jumper wire is used to select the required level (however if you mounted the kit in a case, a knob or switch could be used).
For example, if you’re measuring 3.456 MHz you start with the jumper on H and the display reads 345 – then you switch to M to read 456 – then you switch to the L jumper and read 560, giving you 3456000 Hz. If desired, you can extend the kit with another PCB to create a 5-digit display. The counter won’t be winning any precision contests – however it has two purposes, which are fulfilled very well. It gives the reader an inexpensive piece of test equipment that works reasonably well, and a fully-documented project so the reader can understand how it works (and more).
And for the curious – here it is in action:
[Update 20/07/2013] Siren Kit
Found another kit last week, the Talking Electronics “DIY Kit #31 – 9V siren”. It’s an effective and loud siren with true rise and fall, unlike other kits of the era that alternated between two fixed tones. The packaging was quite strong and idea for mail-order at the time:
The label sells the product (and shows the age):
The kit included every part required to work, apart from a PP3 battery, and a single instruction sheet with a good explanation of how the circuit works, and some data about the LM358:
… and as usual the PCB was ahead of its’ time with full silk-screen and solder mask:
Assembly was quite straight-forward. The design is quite compact, so a lot of vertical resistor mounting was necessary due to the lack of space. However it was refreshing to not have any links to fit. After around twenty minutes of relaxed construction, it was ready to test:
It’s a 1/2 watt speaker, however much louder than originally anticipated:
Once again, another complete and well-produced kit.
Conclusion
That was a lot of fun, and I’m off to make the matching square-wave oscillator for the frequency counter. Kudos to Colin for all those years of publication and helping people learn. Lots of companies bang on about offering tutorials and information on the Internet for free, but Colin has been doing it for over ten years. Check out his Talking Electronics website for a huge variety of knowledge, an excellent electronics course you can get on CD – and go easy on him if you have any questions.
Full-sized images available on flickr. This kit was purchased without notifying the supplier.
And if you made it this far – check out my new book “Arduino Workshop” from No Starch Press.
In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitter, Google+, subscribe for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other – and we can all learn something.
From 1981, Australian electrical engineer Colin Mitchell started publishing his home-grown electronics magazine “Talking Electronics”. His goal was to get people interested and learning about electronics, and more so with a focus on digital electronics. It was (and still is) a lofty goal – in which he succeeded. From a couple of rooms in his home the magazine flourished, and many projects described within were sold as kits. At one stage there were over 150 Talking Electronics kits on the market. You could find the books and kits in retail outlets such as Dick Smith Electronics, and for a short while there was a TE store in Moorabbin (Victoria). Colin and the team’s style of writing was easy to read and very understandable – but don’t take my word for it, you can download the magazines from his website (they’re near the bottom of the left column). Dave Jones recently interviewed Colin, and you can watch those for much more background information.
Over fifteen issues you could learn about blinking LEDs all the way to making your own expandable Z80 board computer, and some of the kits may still be available. Colin also published a series of tutorial books on electronics, and also single-magazine projects. And thus the subjects of our review … we came across the first of these single-issue projects from 1981 – the Mini Frequency Counter (then afterwards we have another kit):
How great is that? The PCB comes with the magazine. This is what set TE apart from the rest, and helped people learn by actually making it easy to build what was described in the magazine instead of just reading about it. For 1981 the PCB was quite good – they were silk-screened which was quite rare at the time:
And if you weren’t quite ready, the magazine also included details of a square-wave oscillator to make and a 52-page short course in digital electronics. However back to the kit…
Assembly
The kit uses common parts and I hoard CMOS ICs so building wasn’t a problem. This (original) version of the kit used LEDs instead of 7-segment displays (which were expensive at the time) so there was plenty of careful soldering to do:
And after a while the counter started to come together. I used IC sockets just in case:
The rest was straight-forward, and before long 9 V was supplied, and we found success:
To be honest progress floundered for about an hour at this point – the display wouldn’t budge off zero. After checking the multi-vibrator output, calibrating the RC circuits and finally tracing out the circuit with a continuity tester, it turned out one of the links just wasn’t soldered in far enough – and the IC socket for the 4047 was broken So a new link and directly fitting the 4047 fixed it. You live and learn.
Operation
So – we now have a frequency counter that’s good for 100 Hz to the megahertz range, with a minimum of parts. Younger, non-microcontroller people may wonder how that is possible – so here’s the schematic:
The counter works by using a multi-vibrator using a CD4047 to generate a square-wave at 50, 500 and 5 kHz, and the three trimpots are adjusted to calibrate the output. The incoming pulses to measure are fed to the 4026 decade counter/divider ICs. Three of these operate in tandem and each divide the incoming count by ten – and display or reset by the alternating signal from the 4047. However for larger frequencies (above 900 Hz) you need to change the frequency fed to the display circuit in order to display the higher (left-most) digits of the result. A jumper wire is used to select the required level (however if you mounted the kit in a case, a knob or switch could be used).
For example, if you’re measuring 3.456 MHz you start with the jumper on H and the display reads 345 – then you switch to M to read 456 – then you switch to the L jumper and read 560, giving you 3456000 Hz. If desired, you can extend the kit with another PCB to create a 5-digit display. The counter won’t be winning any precision contests – however it has two purposes, which are fulfilled very well. It gives the reader an inexpensive piece of test equipment that works reasonably well, and a fully-documented project so the reader can understand how it works (and more).
And for the curious – here it is in action:
[Update 20/07/2013] Siren Kit
Found another kit last week, the Talking Electronics “DIY Kit #31 – 9V siren”. It’s an effective and loud siren with true rise and fall, unlike other kits of the era that alternated between two fixed tones. The packaging was quite strong and idea for mail-order at the time:
The label sells the product (and shows the age):
The kit included every part required to work, apart from a PP3 battery, and a single instruction sheet with a good explanation of how the circuit works, and some data about the LM358:
… and as usual the PCB was ahead of its’ time with full silk-screen and solder mask:
Assembly was quite straight-forward. The design is quite compact, so a lot of vertical resistor mounting was necessary due to the lack of space. However it was refreshing to not have any links to fit. After around twenty minutes of relaxed construction, it was ready to test:
It’s a 1/2 watt speaker, however much louder than originally anticipated:
Once again, another complete and well-produced kit.
Conclusion
That was a lot of fun, and I’m off to make the matching square-wave oscillator for the frequency counter. Kudos to Colin for all those years of publication and helping people learn. Lots of companies bang on about offering tutorials and information on the Internet for free, but Colin has been doing it for over ten years. Check out his Talking Electronics website for a huge variety of knowledge, an excellent electronics course you can get on CD – and go easy on him if you have any questions.
Full-sized images available on flickr. This kit was purchased without notifying the supplier.
And if you made it this far – check out my new book “Arduino Workshop” from No Starch Press.
In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitter, Google+, subscribe for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other – and we can all learn something.
Planet Arduino is, or at the moment is wishing to become, an aggregation of public weblogs from around the world written by people who develop, play, think on Arduino platform and his son. The opinions expressed in those weblogs and hence this aggregation are those of the original authors. Entries on this page are owned by their authors. We do not edit, endorse or vouch for the contents of individual posts. For more information about Arduino please visit www.arduino.cc
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