Sunday, June 28, 2009

Midi to Relay Controller

I've been looking for a schematic and code for a Midi to relay decoder. I finally found one that actually works well. This circuit will work with sequencer software and commands relays or solenoids with Midi. I plan to make a robot drummer controlled by sequencer software. The decoder required turning on several solenoids at the same time with precision, following notes from a drum sequencer. The circuit and code is free and so is the drum sequencer software (DrumFlow 1.7) that I'm using to test the code. My video on youtube show several outputs turning on at the same time. Just what I wanted. You don't need to wire up all 32 outputs, just use what you need and eliminate the other driver ICs. With just a 16f84 PIC and two other ICs you can drive eight drummer solenoids. Thats enough for a hell of a drummer.

Wednesday, June 10, 2009

Hard Drive Afterlife

So your aging hard drive can't hold its data any longer and you replaced it with a new one. Instead of letting it die by the hands of the recycling undertaker, you force it into a new life as a musical noise maker. A dying hard drive makes all kinds of grunts and groans as it starts up. The sounds it makes can be musical and percussive.

This project uses a homemade PIC midi interface to allow sequencer software (Anvil Studio free) to turn on and off eight hard drives. Midi signals are serially transmitted by the sequencer software as sets of 3 bytes at 31,250 baud. A PIC 16F877 has been programmed to receive these bytes to turn on and off solid state relays. Each hard drive needs 5 volts and 12 volts to run. Two SSRs are used to turn on and off the hard drive. I tried leaving on just the 12 volts, then switch on 5v to start the drive up. This worked well for awhile until one smoked up. So I use two SSRs to switch on both 5 volts and 12 volts at the same time. A modified PC power supply is used to supply power. A tuner pickup and computer soundcard amplifies the sounds, making the point that something went horribly went wrong with those drives.

The project is for testing the idea of making a larger kinetic/musical artbot "tree" consisting of 24 hard drives. Each hard drive will be mounted as a branch extending from a central trunk in a circular spiral.

This is what happens when you don't throw away broken stuff, you make something cool out of it.

Schematic here.
Pic Pro Basic Code here.
HEX code here.

You can download an mp3 file of the sounds here.
Email me (see my webpage) or leave a comment to check for updates as the code is evolving.