As I wrote a little while ago, I submitted a solution to IBM's Ponder this for February 2013. I was a bit of a pain in the butt since I first submitted an html file with no content. Oops. After sending the correct file, they reviewed it, and apparently my answer was suitable. You can see my name at the bottom of the webpage. Yay!
Time to Complete: 30 min
The Light Harp is essentially a theramin with light sensors controlling the volume and pitch of sound. I only had one light sensor that worked in the visible spectrum (the top one in the photo). I think the one on the bottom is a UV sensor. Needless to say, it didn't work to control the volume. The top sensor worked well to control the pitch as the video below demonstrates. You can also see my stylish Angry Birds bandage covering up my attempt to slice off my thumb while doing the dishes.
We were introduced to the speaker and the audio amplifier in the Tune Player project. The light sensor makes its debut in this project, referred to as the LDR. The program for this experiment is similar to the previous project but with the appropriate corrections to allow for the light sensors to control the pitch and volume.
As you can see in the video, the right light sensor controls the pitch very well, but the sensor on the left does nothing. I wasn't so what the light sensor on the left was rated for but after looking at the package, I'm pretty sure it's a UV sensor. It's times like these that make me wish I had little electronics stash with tons of sensors and such. Sadly, at the moment, that is cost-prohibitive. Someone (me) needs to hurry up and graduate so he can get an adult job.