It's just a photodiode, a 9-volt battery, and a little amplifier, but it makes the vibrations in artificial light audible. A lot of what you hear is derived from 60Hz AC power, but electronic displays have tones of their own.
Scanning a handheld magnetic pickup back and forth over the piano strings makes a pretty neat sound. I may try attaching a rail on which the pickup can slide back and forth.
The pickup is plugged into an ordinary guitar amp.
Plug: Fun with Sensors workshop this Saturday at NYC Resistor!
I’ve always thought the patterns on corncobs looked like player piano rolls. So I wrote a program that watches a slowly-turning corncob. Whenever a particularly dark kernel crosses the centerline of the image, it plays a note corresponding to the height.
You can download the Processing code from moonmilk.com/11/02/cornscan.txt.
On the way to SHARE last night, I packed a contact microphone and drumsticks but no instrument, telling myself I’d find something in the garbage on the way there. What I found was this nice metal garbage can lid.
Practice for Saturday’s laser whistle workshop. It’s cut from 1/4″ poplar. I won’t post the cutting plan until I figure out why only one of its two whistles is hooting and fix the problem!
NYCResistor rescued a battered old upright piano that was destined for the dumpster. There were 6 missing hammers right in the middle, so I made a quick and dirty set of replacements. Surprisingly, they have a sound that’s pretty close to the original hammers.
The hammers are lasercut from 1/4" poplar, glued together in pairs to be 1/2" thick and then sanded down to 0.4" to match the original hammers. The extended slot in the bottom allows me to glue the hammer onto the old broken shafts instead of replacing them, and to tilt them to the right to hit the strings at the right angle. The felt is some wool stuff from a craft drawer. Real hammer heads are mostly felt, but I made these ones mostly wood because it was easier.
Plans and instructions at www.thingiverse.com/thing:6242