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# Circuit for a simplified DIY galvanometer? Answered

I'm putting together a DIY performance lighting show set as a project and I'm currently working on the laser aspect of it. I've looked into the Galvanometers, which are used in laser shows and those units go anywhere from \$60 to \$200 a pop. So One thing is that I don't need to create any advanced imagery, I just need to vibrate a mirror at a fast enough rate in order to make a laser spread. My current solution is this:

https://imgur.com/a/Cb6ev

Basically a small motor pivoting a mirror along the axis. What I am wondering is, is there something more suited for this that isn't a motor or an expensive galvanometer. I've seen people attach a small speaker and supplying a pulse signal to make the speaker membrane rock back and forth. The volume of the sound would control the amplitude of the vibration but the downside is that it's actually audible, even more so than the motor.

I remembered this episode of ElectroBoom, where a coil wound around a hollow cylinder would produce a magnetic field which would pull a metal object towards the center.

https://youtu.be/mdZo_keUoEs?t=1m54s

Before I would go off trying to attach a metal rod to a spring and repeatedly turn the electric magnet on and off to simulator osculation. Perhaps people would know of something like that which already exists?

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## Discussions

Old hard drive - the positiong arm is quite precise if you can make a suitable cicuit to drive it.
Angular movement might be less than a galvo but speed is good.

Disassemble a laser scanner?

A galvanometer is a just a meter movement, buy cheap ebay analog multimeters?

A stepper motor, over a single step, acts just like a galvo. Find a very coarse one - they exist for this sort of application.

Air pressure on a foil mirror...
Put reflective foil over a closed opening, add pressure and the membrana moves.
Place the laser at the right angle and you get a big deflection.

glue a small mirror on to a speaker cone. Shine laser on mirror, send sound to speaker to give a oscilloscope type fisplsy