[This project was featured on instructables.]
Building an XY laser display “scanner” using a couple of 80W speakers.
I looked into doing something like this way back when I was developing the laser harp – but I came to the conclusion that it would not be accurate enough – turns out as I wrong. This project was created by nothinglabs as an entry to win the laser cutter on instructables.com. The provided library can render scrolling text, and lets you create simple shapes.
What I find even more amazing is that no DAC is used – the speakers are “absorbing” the high frequency components of the PWM signal from the Arduino – although the switching frequency needed to be increased from 500 Hz to 64,000Hz to keep it out of the audio range. I would suspect that the driving (lower) frequency would be low enough to just be in the bass audio frequency range – so it wouldn’t be too hard on the ears when it was running.
Since the needs for the laser harp are relatively simple – this technique could be used to make a single axis controller. The speakers may not give much of a divergence angle, and so you would need a long throw – however with some careful mechanics it might be possible to increase the angle without too much error creeping in.