Useful Tools - The Buzzbox

by Phil Parker

This is probably the most useful tool I have ever made. As well as model railway use it was invaluable when re-wiring my car and can test wires, fuses and light bulbs.

Basically it is a buzzer in a box. Power comes from a 9V battery which has lasted many years without replacement. For extra effect I wired an LED (with appropriate resistor) into the circuit.

Since I’m not good at drawing circuit diagrams and if you need one you won’t understand it anyway, here is a quick description:

Connect one side of the battery to one side of the buzzer. The other side of the battery has a long wire attached to it, as does the other side of the buzzer. These are the test leads. When you touch the free ends together, the buzzer will make a noise.

Now I made my tool a little more sophisticated, the leads plug into the box as I thought making them removable might make me less likely to break them. On the end of one lead is a probe made of an old propelling pencil. On the other lead is a croc clip. The whole lot is housed in a box from an electronics store (Maplin now, but my tool is so old that I probably bought it from Tandy !)

That’s all there is to it, simple and very effective. The main role is testing that gaps made in PCB track are complete. Wiring the layout, or at least finding out where things have gone wrong, is much easier. You need to avoid testing wires with power in them but that doesn’t seem to be too much of a limitation.