I keep looking into a low cost, yet stable way to generate nice sine waves which are controllable, using something other than a signal generator or one of the cheap breakouts which never seem to work that well. This led me to considering audio systems as a possible source of signal. It turns out that the iPhone app store has a nice little tone generator app – aptly named “Signal Generator“.  The app has a frequency range from 100Hz to 20Khz. Connecting the output of this into an oscilloscope shows a really nice signal. I worked on buffering this through an op amp, and sure enough, it works great! So, could an enterprising person use an old iPhone as a driver for a galvo…? If anyone is interested, I can send over my inverter+amp design for you!

I made a short video showing the results – I hope someone can make use of it!