A toy to conjure with

When I was young I had an educational toy that was called something like an Electrokit (definintely not the Meccano Electrikit). It was a set of electronic components, each protected in a chunky housing with standard split-pin plug fittings at the bottom. You then got a series of circuit boards with appropriate sockets in and you could plug the transitors, resistors etc. in place to make up real working electronic devices.

I can't find a picture of the kit or the door, so here's
the Science Museum
As far as I can remember, and I'm really dredging the depths of memory here, it was brilliant. I feel a real nostalgia for this kit. The ultimate thing you could construct was a radio, which was quite exciting, but for me this wasn't anywhere near as good as another project. The thing is, a radio was an everyday item, but you also got the chance to build something cool of practically Star Trek wonder.

Before I reveal what this project was, I ought to point out something I have since shown to my children at the Science Museum in London. I don't know if it's still there, but last time I went round this particular part of the mueseum I spotted an antique exhibit of an automatic opening door. The first time I went to the Science Museum, aged 6, this door with an 'electric eye' was absolutely mind boggling. You walked up to it, and it opened. Automatically. Like magic. I must have gone through it about a dozen times. This was the future. Really.

So given this context, here's my favourite project with that home kit. As well as the basic electronic circuitry you added a buzzer (and possibly a light) and a pair of wires. At the end of the wires was a little panel with a series of conducting bars. This panel broke the circuit - the buzzer didn't go off. But if the panel got wet, the water conducted electricity across the bars and the buzzer sounded, controlled by a transitor on the board.

So what you could do, for example, is tape the sensor to the side of the bath and leave it filling, careless not bothering to watch it. Surely it would overflow, causing terror and destruction? No! The amazing technology started to buzz and you could turn off the taps. Ah, joy, pure joy. This was twenty-first century living in the 1960s.

Picture from Wikipedia