Equipment

I mentioned awhile back that I'd been playing around with electronics with the intention, inter alia, of producing a piece of equipment for use in our lab. The item in question seemed trivial when I first decided to build it, but as is so often the way, turned out to be a little more complicated than I expected. Nevertheless, the final product has now been deployed, and it looks like this:

Its purpose is to ease the process of electrolytically chloride-coating the silver electrode wire used in a patch clamp or SICM pipette. This is something that we've previously done with an ordinary 9V battery and some crocodile clips -- fiddly and annoying, certainly, but not a major ordeal. Turning it into a personal electronic engineering project was, let's say, unnecessary, but it gave me something to play with -- and I quite like having made my own little contribution to the lab's gadgetry. It's almost like being a proper scientist.

Despite its lack of motors, sensors and lethal laser weaponry, what I wound up making was, basically, a robot. Specifically, a BEAM robot. The timing is controlled by a grounded bicore with variable resistors on both parts of the duty cycle, and the outputs are switched by an H-bridge motor driver. I don't have a proper circuit diagram to hand -- it as all cobbled together out of sketches and breadboard prototypes -- but here's a schematic of the stripboard layout I eventually settled on:

For all its superfluity, it's a cute little gizmo and I had fun making it. And the chloriding process is definitely easier now. Those few minutes a fortnight will make all the difference, mark my words.
Posted by matt at July 7, 2008 08:31 AM