This time for the optical tremolo pedal that I built. What makes this tremolo pedal different from any other, you ask? The answer lies in it's name: Optical tremolo. Yes, that's right, this tremolo uses light to create the volume changing effect that is a tremolo. This is how it does that:
And LED light is positioned above a photo resistor, and a motor spins a disk with a pattern cut out of it . When the disk spins, light can shine through the patter cut out of it, thus hitting the photo resistor.
When light hits a photo resistor, it's resistance increases. So when you run a signal through the photo resistor while you have the LED lit and the motor with a pattern disk spinning, you get a pattern of varied resistance (and therefor volume) that corresponds to the pattern on the disk. Voilà! Tremolo.
I got the idea for this project from MAKE: Magazine Vol. 15, but you can read the article online for free here: MAKE: Optical Tremolo
Everything is powered off of a 9 volt battery.
The only controls on the tremolo pedal are a switch to reverse the motor (For A-symmetrical pattern disks), a 5-way switch speed control, an "amount" potentiometer (wired in series with the photo resistor), and an on/off switch. Watch a video demo on my Youtube channel!
Finally, here are some pictures:
(Pattern disks aren't pictured, because I seem to have lost them... Haha)