Using the open hardware Stimmmopped, you can tune your stringed instrument using you eye rather than your ear. It works by illuminating a string with two lights, which are flashing at the frequency that the string should be vibrating at. If the tuning is off, the string will vibrate slightly faster or slower, so the illuminated part of the string will appear to be moving (due to the stroboscopic effect). Once the string is in perfect alignment, the lights will appear fixed in position. It’s certainly not a new idea, however this version looks like it was designed quite well. Cool project!

I’m also guessing that you could have some fun with it as a musical note generator, if you use some photocells to pick up the frequency of the flashing lights… [via embedds]