An overview

There are disappointingly few low tech, low cost laser scanning systems out there these days. All that is going to change with this project. I aim to create a small, portable, sub-$50 laser projector that can display useful resolutions. It doesn't have to be colour, it does have to have different brightness levels. Ideally, I would develop this to the point where I can take a laptop with a broken screen and turn it into a roaming projection system. Realistically, I give myself a 5-10% chance of success. That's enough for me.

Topping my list of ideas in terms of practicality and suitability is VGA pixel stream driveo piezo mirrors or acousto-optic deflectors. These can diffract light, letting me control the reflection angle of light via oscillation frequency - if I can get good enough equipment this is a real possibility. To this end, I've ordered a bunch of piezoelectric sound wave transducers - the should be here sometime next week.

Coming a close second, and something I'll definitely have to play with if only to find out whether it works, is sound driven displaying. If I assume my computer sound can output a maximum of 22khz, then it must have a sample rate of at least 44,000 samples/second (two samples to describe one wave). So in theory, I could use that to differentiate a maximum of 44,000 pixels per second -- using stereo channels to control horizontal and vertical. This limits use because we need at least 30 refreshes a second, so we could display something in the order of 50*30 pixels before we had to resort to nasty tricks to compress the information. Of course, this approach scales up, so we could use USB sound outputs to drive a whole bunch of these and get decent resolutions. The trick is working out how to use the waveforms to draw the pixels efficiently.