Books written by Ray Sullivan

Monday, 25 August 2014

Cheap as chips

There's an oft used phrase in the UK, 'cheap as chips.' I've always assumed that it refers to the ubiquitous and usually inexpensive food (fries to you guys across the pond, not the wafer thin slices of baked potato we call crisps). Probably, but perhaps there's a 21st century version ready to take over.

Many years ago, as a teenager, I got into electronics. My parents gave me a science fair solderless electronics kit to cut my teeth on and I progressed onto buying radio kits, dabbled with simple synthesizer circuits and bought electronic magazines for a few years. I didn't delve into the theory or mathematics too deeply - I wasn't much of an academic back then and in fact left school without a qualification to my name. In fact it wasn't until I was in my thirties that I started building up an academic profile that now includes a good honours degree in mathematics, professional recognition as a mechanical engineer and a teaching qualification.

I had thought about a career in electronics back in the day but where I was raised was very heavy industry and one of my first jobs was in the local steelworks with thirteen thousand other locals. The steelworks is a shadow of its former self now, employing less than a thousand, but the area is quite high tech these days. Nonetheless, my lack of qualifications would have been a major barrier back then. I'm guessing my colour blindness would have hindered me somewhat, too. Or maybe not, my first job, before the steelworks, was as an apprentice electrician. They never asked about colour sight and I didn't mention it at the interview. I guess they worked it out reasonably quickly - pulling red and green cables in the wrong order, which looked much the same to me before they were coated in a lubricating chalk dust, was probably a bit of a giveaway. However the bosses were probably a bit embarrassed that they didn't check when they offered me the job so, after 15 months I unilaterally bailed out without my colour sight ever being mentioned to my face.

The Air Force were careful to check my colour sight as part of the entrance medical, in fact they initially categorized me as too colour blinds to drive Service vehicles - all those pesky green and red traffic lights - until it suited them to have me drive a van full of armed guards. Then a deft change on a database - no medical or book full of seemingly random coloured dots - did the job. But they weren't up for me meddling with multi- million pound electronic kit, so it was mechanical engineering for me. In fact, at around the time I was building a useful set of qualifications, I became a bit of a specialist in hydraulic engineering which I discovered through my applied maths course is entirely synonymous with electronic engineering. You can use what is called an H state transformation matrix to convert any hydraulic formula up to and including second order differentials to the equivalent electronic formula and vice versa.

Anyway I decided to start dabbling in electronics again recently. My wife bought me a starter kit of components for my birthday and the relevant 'for dummies' book. I'm not a big fan of the 'for dummies' books with their patronising and stupid jokes, but I do find them useful for doing a shallow dive into technical subjects. By the way, I suggested the book, my wife was only following orders! The book, for anyone contemplating it, is ok. Just. There are a few circuits I'm currently adapting and I found the chapter on capacitors blew away a number of misconceptions I'd held since my teens. The descriptions for semiconductors isn't that clear, but my hydraulics background helps here. For diodes I read check valves, for transistors I read pilot operated check valves. You can't stretch the analogy too far - hydraulics is much wetter but burns less. Throw in flow control valves for resistors and accumulators for capacitors and any hydraulic engineer worth his or her salt should be able to understand basic electronic circuits quickly.

The starter kit didn't match the projects I wanted to build so I popped over to eBay to see what was available. I'm blown away by the affordability and range of components out there. 100 general purpose transistors, similar amounts of GP diodes, about a pound or so including postage (sometimes from the UK, others from China). Timer integrated circuits and decade counters a few pence each if you buy enough. So the chips are as cheap as chips, literally, and probably healthier, although the amount of time I'm spending hunched over a breadboard (chip butty, anyone?) probably isn't too healthy. My alter ego, B L O'Feld, has a list of evil projects he wants me to build including the staple of evil genius', the countdown timer. Just a heads up, if you try to disable one of mine in the time honoured tradition of choosing to cut the red or the blue wire - oh the dilemma - just remember that with a colour blind builder the options are nowhere near as easy. Careful with those snips!

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