March to the beat of
a very different drum.
impact sensors in PVC
pipes interface to a
micro drum machine.
By Tom Zimmerman
An electronic drum is basically a switch that triggers the playback of
a digitally recorded drum. Here’s how I built tubular drum controllers out
of PVC pipe and connected them to a studio drum machine to create
a professional-sounding electronic drum kit.
Each controller has a guitar string suspended so a pulse-stretching circuit lengthens the signal,
above 4 strips of aluminum tape. When you strike by charging a capacitor.
the string with a drumstick, it touches the tape Two male-to-female serial cables let you unplug
and closes a circuit to trigger the corresponding the controllers from the drum machine. I cut the
sound from the drum machine. Foam covering the cables in half and connected them to the controllers
pipe softens the blow and provides a nice bounce. and the drum machine. To plug-and-play, you simply
Underneath each controller, a pressure-sensitive mate each connector to its former other half.
piezoelectric device lifted out of the drum machine
detects the force of the hit, to determine the relative
Tom Zimmerman is a member of the User Sciences &
The brief contact between the struck string and Experiences Research laboratory at IBM’s Almaden Research
the foil is too short for the drum machine to detect, Center. An MI T graduate, he was profiled in MAKE, Volume 04.
Photograph by Sam Murphy
88 Make: Volume 15