A while back i posted this, and it’s been sitting on the self for quite some time! I pulled it out the other day to use as a project for my course, as an example of how cmos chips can be tricked into producing entertaining techno-esque-squelchy-ish sounds.

Its only capable of square wave synthesis, but whats the harm in that when it produces noises like this! With a few extra components you can convert the output into different wave formations, but at that point we start getting into proper synth building, so we’ll keep it simple for the time being.

Since the last post about this, I’ve been adding a few extra circuits, but kept the original which contained an interesting starve function for the vactrol. To be honest it was a complete accident that i found this, as its not your usual starve circuit that restricts the current to the output, but it works, and nothing melted, which is always nice, so it stayed.

I’ve had a few emails about this, but i’ve never documented it, which i am in the process of doing just now. So hold your horse’s, somethings coming shortly with schematics and if i get round to it…. Eagle files as well.

Several years ago I used to co-promote a club night in Glasgow called Cypher, with my good friend Chris and a lot of help from some friends, mostly the dark-haired one called D (cheers!).

We “acquired” an Optisolar 250 gobo projector, and we spent a small fortune on a metal gobo with our logo for the events. I was always intriegued to see if it would be possible to build a small, portable slide projector for advertising purposes, something we could mount in the street and leave, so it had to be cheap enough and easy to build so that if it was stolen/broken/confiscated then it wouldn’t be any great loss. But as usual it was always just a bit of a pipe dream, until now.

I’ve been playing around with this again in recently, and so far have tried a number of options involving Luxeon LED’s, 35mm slides, small LCD displays, Li-Ion batteries, various lenses(from slide projectors, cameras telescopes etc) and a host of other components for constant current circuits, and more recently i’ve been investigating the use of lasers for this project.

There’s a few sites around these days with similar ideas and inspiration.

Graffiti Research Lab Seriously good projects to combine graf and electronics. Unfortunately i dont have a powerful projector at my dispossal, plus its likely to be stolen, broken or confiscated round these parts, and ideally I want to mount this and walk away for these reasons, so its got to be “disposable” in a sense.

Troika A London based design collective who developed an ingenious hand held battery operated projector, that displays text messages! Not sure what their light source is, but it looks like their battery pack is a separate unit judging by the wire that disappears up the sleeve of the operator. A highly professional finish though like all their projects. I’d love a peek inside that thing.

Intructables.com Loads of good tutorials for building things. Recently echo_anomie added his own instructable for his laser powered projector. He’s got some fantastic results out of it, and if my finished unit performs half as well then i’ll be happy!

“Reach for the lasers, safe as fuck!” er…. not quite, lasers will blind you kids! ;o)

Another option is to utilise light sources already in place, such as the powerful flood lights that lots of buildings have to illuminate them at night. I’d need to somehow containing the light with a sheet of metal, with a lens and a slide mounted to it, but thats a bit harder to try and test….

I’m still experimenting and writing up a page of its own for this project, so stop by shortly to see if there’s any progression.