My friend Zevin and I had a circuit bending jam session in preparation for an electroacoustic noise show that we are putting together. On our way to my house we stopped at the dumpster behind a thrift shop and scored a crumby old HP inkjet printer. After ripping off the cover, because I couldn’t find my torx wrenches, we discovered that the motor that drives the belt that moves the heads back and forth is DC. This changes everything, since driving a DC motor is just a matter of driving some current through it, apposed to a stepper motor which would require drive circuitry and logic. We hooked the motor up to the output of my stereo amp, and started experimenting with different signals, using Pure Data.
Here’s one, using a saw tooth wave:
And here’s another, using a random signal between -1 and 1, changing every 10th of a second:
Finally the hack came to perfection when we taped a screw driver to the head and drove the amp with a pulse shaped like a single cycle of a saw tooth signal, using the ~vline object in Pd. Then we triggered the ~vline object using a step sequencer I wrote a while ago in Pd, and put a large steel drum in harms way.
This contraption will definitely play a role in our music project. It’s hard to say how yet. It could be used, as is, to strike a barrel or it could even strike a conventional drum. But there are many other possibilities.
I was most inspired during this hack by the acoustic recordings on Aphex Twin’s album drukqs, which I thought were made using devices such as the one above. But Zevin noticed that they are actually compositions on prepared piano, a method developed by John Cage that uses a standard piano. The misunderstanding lead to a unique project, that might not have happened otherwise.