Back in the early 70’s, I was interested in constructing, based on what I had seen on American Tv shows and movies with all the gadgets people could buy and construct. When I saw people on TV use walkie talkies, I wanted a pair. There was nothing I could find to persuade my Dad to help with in the UK. My Dad subscribed to Practical Electronics and Electronic Engineering magazines. I remember my school library also had copied of Practical Wireless and early issues of Everyday Electronics. I used to sneak in instead of doing PE (Physical Education) and read them until the Librarian told me off for reading magazines meant for the sixth-formers.
In out local town there was two shops that sold electronic components and an Audio shop that also had some large transceivers. I went to ask and found out they were Radio Amateur transceivers and their price tag when I informed my Dad was more than the cost of his car and the family first house 10 years earlier. I went back to that shop a few times to ask how to become a Radio Amateur and then as a boy just scraping to get by in Grammar School, going to a College Night School was out of the question. Too much of my own homework, paper round and other chores. The Audio shop had some old books and periodicals for sale and one day I picked up a ring-bound publication from the US titled How to make your own walkie talkie. The shop owner put it to one side so I could save my pocket money and paper round money to buy it.
I never did build the walkie talkies but the valuable information led me to find other books in the local village library and got them to order other books from other libraries for me with the comments that the books were really for adults. I had to get my Dad to come down and explain that it was my hobby so they let me carry on with those adult books.
After building my first Transistor Radio from a Ladybird book bought for me by my Mum and tools given to me by my Dad, I was hooked on constructing things. I couldn’t afford to buy new electronic components so I used to strip down old TVs and Radios from scrap that was thrown out the back of a TV and Radio repair factory. Today that’s called “Dumpster Diving”. We couldn’t afford to but storage drawers so I had old jam jars, match boxes and margarine tubs to keep all my components sorted.
What did I build?
A Transistor Medium Wave (AM) radio on a piece of wood with components screwed down by brass screws. A 1 valve audio amplifier with a more-power that the transistor one I had in my record player. This was fun as my Dad helped me design the chassis and we bent the sheet aluminium into the shape and screwed down the valve base and the connector strips. The hardest part was the power supply and finding the right transformer. Lots of the scrap equipment I had wasn’t suitable in fact some had a “live” chassis. I remember when LEDs came out and I has to save up £5 for a single red led. With a suitable transistor and 2x 555 timers (the design in a magazine stipulate a NE556 which is 2 555 in the same package which wasn’t available in my region of the country). Simple circuit using a LED and buzzer for a timer that could be used in the kitchen. Other projects was the TV Game “Pong”.
Using a “MSI” AY 3-8500 General Instruments chip and other components, I collected in readiness whilst saving up for the chip which at the time was only available from Watford Electronics some 250 miles away. The chip was £15.99 and my Dad knew I was struggling to save that then, I’d need to get my Mum to write a cheque and hopefully the chip would be delivered in a month. As a surprise for my birthday, Dad took me for a very long day out to London, we visited electronics shops on Tottenham Court Rd and Edgeware Rd, then Watford Electronics on the way back up North with my new TV Game chip. I also got a stereo amplifier chassis kit from AMS Trading (That later became AMSTRAD) and some tuning capacitors from Henry’s on Edgeware Rd. and a White plastic sloping front case to build the Pong game in. It was a “Grand Day Out”
General Instruments AY-3-8500 from 1976
To supplement my pocket money, my Dad had a little side job of repairing electronic driver modules for auto gear boxes for buses and trucks which were failing because of no flywheel diode protection from spikes due to the hefty solenoids. The power transistor was an OC35 and difficult to source. So I redesigned it to use a 2N3055 which was plentiful, it just needed another transistor to drive it so the wiring to the solenoid circuits didn’t have to be modified or the switching input. OC35 was a PNP Germanium power transistor where the 2N3055 was NPN. So to get it to switch correctly, the repair involved a BC107, IN4001 and a 2N3055 which all were cheap and plentiful and available in bulk locally. I was repairing a total of 50 of these driver units which after paying for the components, earned me enough money to make my savings bank happy.
The Pong TV Game met a smoky end, somehow it was plugged into the wrong power supply which had the opposite polarity. Lesson learned, make sure you put in “idiot diodes” and a fast blow fuse. From then on, I made a VHF FM transmitter – yes I know the legality, but out in our village, no harm or interference was caused. So I made another and has them either end of the FM band in a quiet spot so my and a friend who was about 100 metres away could talk in full duplex. In fact when we arrived home from our different schools, we found our Mum’s talking to each other with our radios!
After seeing Saturday Night Fever film (had to sneak in the cinema as I was too young) I wanted to make disco lights. The next project! This was so simple and so good, I made another for my Dad to use as he had a part time job as an organist and entertainer. Below is the circuit diagram, you couldn’t build these today as those incandescent bulbs are no longer made. Its only problem was it would cause mains interference which could be heard if the record player was on and the volume was up. Only so slightly and workable.
The design used a Triac and a Diac that would switch at any part of the mains cycle and that cause the noise spikes. Not much since the loads was just incandescent lights that are basically resistance with very little inductive or capacitive reactance. Because the coloured bulbs were different wattages, they would illuminate and cool down at different rates therefore giving a pseudo complex light switching arrangement. The design also taught me about equipment used “on the road” had to be tough. I added audio signal and mains in and out functionality so another unit could be daisy-chained for extra effect.
When I was invited for an interview at a local electronics factory, I turned up with a box of projects and documentation to present to the interview panel. As I remember there was only 2 of the applicants sat in the waiting room with our home-built projects to showcase. All the rest looked like they had come to the wrong place. I got the job and was dispatched to engineering school and back to college on “day release” to carry on and get my electronics diploma.
The electronics company had a few other constructors working in the test department and R&D department. As I had a incoming wage, we all saved up and bought Acorn Atom computer kits and built our own. One of the chaps figured out that he could extend the basic interpreter and add games on an array of eproms which would run the game when its name was entered at the command line, the interpreter would check the other eproms first before returning a syntax error. Great! We took turns at buying a game eprom, then we would clone them at work during lunch times.
What’s topping you from becoming an Electronics hobbyist? Nothing!
Today, components and kits can be purchased online for very little. Ideas and projects are plentiful and a simple internet search will reveal 100’s NO !…. 1000’s. Tools and test equipment is cheap as chips and you don’t need to have a PHD in electronics since the majority of components are modular which the only limitation is you. You don’t have to dream of ideas then put them on reams of paper whilst saving up to buy components to test your theories. Complete experimenters kits with all the components and “breadboard” are included for £15.
Arduinos and Raspberry Pi have spawned a whole industry around maker projects. I even find it is cheaper to use an Arduino to build logic solutions than spend money buying discrete logic chips and wiring them up. Everything can be done through an App. Even breadboard is becoming “wireless” with a new idea that components can be just plugged in using a stylus, point at connections to have the device “connect” them together.https://www.youtube.com/watch?v=ECoV4VeyLQs&list=LL&index=37
Try this to get you going:-
