Rhythm & Detonation


This is a crazy project that started when Jesse Anderson asked me about the Death By Audio robot pedal. It's a very lo-fi 8-bit pedal that makes your guitar sound like a robot, but for whatever reason, DBA charges $320 for this effect, an adaptation of the $5 Holtek HT8950 chip, which is a "robot/voice change" chip used in toys.

It turns out the chip has a lot of features that the DBA pedal doesn't tap. I found a related project at General Guitar Gadgets, called the DH pitch shifter.

Most of the heavy lifting of this pedal is done by the Holtek Chip, which has a lot of built-in effects. The chip does robot voice and vibrato, and has seven steps of pitch shifting.  Adjusting the clock speed of the chip offers further modulation by raising or lowering the pitch of the pitch shifting, and changing the speed of the vibrato . The pedal also has a simple mix function that allows you to control the mix of the effected signal and the clean signal.

The pedal is painted in hugger orange, and the graphics are an image of the ENIAC computer.