Australian Electronics Nostalgia – Talking Electronics Kits

Introduction

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):

cover

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:

pcb

pcbrear

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:

LEDsin

And after a while the counter started to come together. I used IC sockets just in case:

almostthere

The rest was straight-forward, and before long 9 V was supplied, and we found success:

powerup

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:

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:

kitbox

The label sells the product (and shows the age):

kitlabel

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:

kitparts

… and as usual the PCB was ahead of its’ time with full silk-screen and solder mask:

pcbtop

sirenpcbbottom

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:

PCBfinished

finished

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.

LEDborder

In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitterGoogle+, 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.

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John Boxall

Founder, owner and managing editor of tronixstuff.com.

15 Responses to “Australian Electronics Nostalgia – Talking Electronics Kits”

  1. Steven jepson says:

    I remember building one of those when it first came out. I think its still in the shed somewhere.

  2. Scott says:

    Thanks for sharing that. I learned a lot about electronics from the Talking Electronics magazines. There wasn’t a schedule – I think each issue was printed “when it was ready”, so I was constantly looking for them at the newsagent. Colin had a gift for explaining technical things in a language that the layman could understand and the lack of advertisements meant that there was a lot of rich content in a relatively small magazine.

    I always wanted to assemble a TEC-1 computer, but as a teenager I didn’t have the cash. Last year, I was fortunate to be able to buy one of the last TEC-1 kits and have found it quite entertaining to go back to entering programs in hex and do some really low level programming.

  3. Sleepwalker3 says:

    Yes, I think I built one of these back in the days, I was still in high school I think. I also have a host of the old Z80, the I/O board, DAT board, and various related kits that I got quite some years later, some still unbuilt, as I was getting busy in my new job. I recall the place in Moorabbin, just a house and you had to go around the back, there was stuff *everywhere* if I recall correctly!

  4. Scott says:

    The two-tone siren reminded me of the FM “wireless microphone” kits from Talking Electronics. Their competitors’ kits were poorly designed and had very little range and terrible frequency stability, while the TE wireless microphone kits had great audio quality and seriously useful transmitter range. Back when a “WalkMan” was a pretty expensive device and way out of my price range, I used a TE FM transmitter kit to broadcast music from my tape player to a pair of radio headphones.

  5. Kilby says:

    I remember working there or shell I say I worked more on his house or the shop in Moorabbin than the magazine (TALKING ELECTRONICS). Most of the time we just blinding Kits and selling them on. I found Colin Mitchell hard to work with that’s why in the end I left TALKING ELECTRONICS. Somehow I found TALKING ELECTRONICS website if you can call that. Funny thing is I’m a Graphic Artist, no longer work with electronics the only memory there is working the small offset press. And wish I had it to play round with. There only one guy I liked there but it’s been that long I forgot his name. But he the one that invented most of the kits at the time like the phone bug that let you call anywhere around the world to that number and lessen in on what going on in the room. One very clever man, I wished him well.

    Regards D Kilby

  6. Robert Scott says:

    I remember these from the early eighties and in fact built one. Is the PCB artwork and eprom image still available somewhere ??

    Regards Rob

    • John Boxall says:

      Hard to say. You can ask Colin if he’s up for a chat…
      http://talkingelectronics.com/

    • Robert Scott says:

      Thanks for that but it says the site doesn’t exist or not available. I managed to obtain images for the 2716 / 2732 eproms from Ken Stone but no pcb artwork using the 74LS273′s. I am an electronics tech of 40 years plus and have done a lot of PCB design work using Autotrax 1.61 for DOS. I wanted to look at the artwork and redesign artwork using double sided board. I have the schematic from Talking Electronics issue 14 also I have issue 10 & 13. I have Ken Stones artwork from the issue 10 back page but the later design looks better from what I can see from the pictures of the latter kits.

      Regards Rob

  7. Austin says:

    Hi John,
    I remember buying and building my first TEC-1 computer, followed by the 8×8 LED matrix, and relay driver board. Working for the old Telecom at the time (1983) I programmed mine to dial telephone numbers, using the old pulse dialling (make/break contact) method – very ‘low tech’ by today’s standards, but it worked, with correct timing in place (after some ‘tinkering’.)

    Being a young trainee, I didn’t have the ready cash to buy a Microbee Z80 like the older men did in my section, but they couldn’t figure out how to do the simple programs I did on the TEC-1 either. They used to laugh at me and my TEC-1, but I learned a lot more about machine language back then, as they all went to an assembler for convenience’ sake. None of them could do the ‘dial phone numbers trick’ – not even close…

    I vividly remember writing the “You’re Dead” program, which scrolled those words across the 6 x 7 segment displays, and then played the ‘funeral dirge’ – lots of fun and informative. I forget which magazine edition it was published in, but I do remember passing out copies to all the fellas at work, with the challenge “see if you can do that!” They couldn’t!

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