Our works Christmas party requirement is for festive hats and I told the secretary I’d do something awesome – problem is I don’t know how!

What I want to do is build a 9v circuit to move a servo/ stepper motor backwards and forwards every 2secs to wave a hand but I’ve started to realise I don’t know how.

I can’t let tasty secretary down so anyone have an idea where to start? I was thinking about the old 555 timer chip and a servo but that’s where my skills run out!

I’d buy something that already did what you want and rip the guts out of it. Some toy or novelty item. If you do want to build from scratch then you can buy a servo tester which will cycle a servo motor. They’re only a few quid. They tend to run from 5v, though, so you’ll need a 5v pack (4x AAA) or a 7805.

^ ditto the above. look for a servo tester kit. Most have a square/sine wave mode.

or you could do it mechanically – think steam locomotive type linkage on a normal DC motor. But getting a low speed will be tricky.

Wot about this?