Saturday 19 September 2015

A clock?

Ahmed Mohamed made a digital clock, took it to school, teachers over-reacted, police over-reacted and now the whole USA is over-reacting.

Of course it's bad that a 14 year old kid gets arrested for showing off his neat project, but that's an obvious consequence of a "zero tolerance policy", which means, guess what, tolerance is thrown out of the window. It's inevitable that a zero tolerance policy will lead to a lack of tolerance (duh) and to really stupid decisions.

But apart from the over-reaction of the teachers and the police, what I'm seeing now is an over-reaction by the rest of the USA. They're treating him like he's some sort of electronics genius.

Try google. You can buy a kit for making a digital clock for £3. It really isn't that big a deal. With modern electronics, it's an LED display, a couple of ICs, a crystal and a few assorted components.

When I was his age, I built:

A crystal radio, using parts salvaged from broken TVs
A transistor radio, which was my crystal radio, two transistors, and more parts from broken TVs
A valve tester (this was 52 years ago, valves were more common than transistors).
A amps-volts-ohms meter (building your own is cheaper and more fun than buying one).

And then I started to get fancy. I built a couple of analog computers, a machine for playing (and winning) a game called "hex", and a digital computer made from Meccano (I worked out how to do an OR gate, an AND gate and a NOT gate) that could reliably add one and one and get two. Meccano was also the hardware base of most of my electronics projects.

Meanwhile, of course, I was doing chemistry. You could buy a pound of sodium chlorate at Boots (they thought it was weedkiller, I knew that it was one component of an explosive, the other component being sugar). Nitrogen tri-iodide, an explosive so unstable that once it dried, a touch would set it off (ammonia from Boots, they thought it was a household cleaner and iodine, which they thought was a disinfectant). With bleaching powder (calcium hypochlorate) you could make chlorine gas, with caustic soda (sodium hydroxide) you had an alkali so powerful it would burn your skin, it was easy to get the components for gunpowder. I never took any of that into school, I wasn't stupid.

And physics. I made an electricity generator, a steelyard balance, an electric bell.

But I did take some stuff into school. I made a little box using a metal mustard tin, and a layer of aluminium foil on one side, insulated from the tin. And there was a switch on the side of the tin. This would be left on my desk, and some curious classmate would pick it up and switch the switch. The battery inside would send a surge through the primary coil, the secondary coil amplified the voltage, and you get an electric shock in your hand. Only a small one, though. But if you made the mistake of switching it off again, the back-emf would send a mighty jolt.

I didn't get expelled.

I built a machine that could follow a white line; I used a post office uniselector and hardwired the terminals to provide the logic for the machine. I built a machine that would come to you when you whistled at it, using the components of a tape recorder and lots of meccano (and I made a cover for it so it looked like a dog).

And when I went up to university and discovered the delights of tinkering with a bicycle.

What put paid to all this was a) bridge and b) girls. And when I left university, I found myself at Marconi-Elliott at Borehamwood and they had an Elliott 503 and because they owned the machine, I could use it as much as I liked, which was a *lot*, and I got enchanted by Algol (which is a lot like Turbo Pascal, and a lot like Perl) and I spent the rest of my life playing with the greatest toy ever invented, the digital computer.

A clock?

1 comment:

  1. An under appreciated feature of NI_3 is that if you detonate it before it's completely dry, the wet bits don't all go off but get scattered around the lab. With a few iterations, you can cover a surprisingly large area without much effort. If I had my time again, I'd probably not make it the day before the A-level chemistry practical exam though!