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Percussus    The Drum Machine

A drum machine made with midi controlled relays. A PIC microcontroller decodes relay on/off codes from a sequencer program.

 Below is a photo of the insides with the top removed. More photos at my google photos site

At the left is a guitar pickup that amplifies the percussion like, click clack sounds of the relays. A second microphone was later added.

Toward the right, inside the box, is the homebuilt 8 channel midi controller.

I got the unfinished box at Michaels craft store for $5.99. Better than one I could make. The light pine wood has nice sound qualities too.
The box was then stained and finished with semigloss brushing lacquar. Flat black sprayed inside to enhance the flashing leds.

Won the Gold medal in Musical Artbots at Robogames 2010
Won the Silver medal in Musical Artbots at Robogames 2011

  Construction before adding the leds. Lots of room still left inside.

As the relays are activated, leds flash with the beat. The leds are mounted on a piece of cedar flooring finished with  lacquar.
Both a microphone and contact pickup is used to amplify the sounds to produce a stereo signal with a mixer circuit.

Leds connect to the PIC midi interface.

The LM2876/3876 based 30 watt amp "Gainclone amp" to boost the sound of  Percussus. The amp will be mounted in a guitar amp style box.
I used an old microprocessor heat sink to kept the chip cool. The PC board was a free evaluation board from National Semi in 1993.
The relays were all bummed out, old obsolete relays I had laying about. A second box with two large contactors, a solenode and strobe was added in 2011.
A mp3 file as a sample
WAV files for each note:
Schematic of the PIC midi interface here.
You can get the program and how to build your own interface at this site.
Hex file for operation on midi channel 10
Go to my other website for more Robots and Artbots.
Updated 4-28-11