Midi Controller Pedal

Ever wonder what you could do with that old volume pedal or that broken wha wha?
I have been teaching myself how to program the Pic microcontrollers using PicBasic Pro, and in the process I came up with this nice little circuit, with it you can turn any old volume or wha wha (or any old continuous controller) pedal into a midi controller pedal.
The pedal is hard coded to transmit on channel 1 (but I can program it to any channel) and you can select between 8 midi controllers by an internal dip switch. The circuit is set up for use with a 10k potentiometer, and is self calibrating, just set the pot to maximum, turn on the unit and it will calibrate itself. On my prototype, I put the on/off switch at the front (under the pedal) so to turn it on you press the pedal all the way down, then press a little bit harder to activate the switch. It takes a few seconds to calibrate itself, so keep the pedal down for about 3 seconds. The only drawback to this setup verses a manual on/off switch is that this method may decrease your range a bit, the pedal calibrates itself at the pot position when the switch is pressed, but in actual use you will not push the pedal down that far (otherwise you will turn it off) so instead of a range of 0-127 you end up with a range of 0-120, although I have found that once you get a "feel" for your pedal, you can back it off a little bit to get the full range (this would have to be done within 1 second of the switch being activated)
I could program in a 2 or 3 second delay before calibration to allow for repositioning the pot, which I will probably do on my next prototype (or whenever I get off my lazy ass, and pull the chip to reprogram it)
I also incorporated a bridge rectifier and voltage regulator so it can be operated from any power source 6 to 24 volts AC or DC
The circuit board is only 2.5" square, so it can be mounted inside your pedal and run off a 9v battery.

Revision 2 pedal

I have updated the circuit and program for this revision, so it no longer needs to be calibrated, the main pedal can be set to any of 4 controllers by an internal dip switch and I have added two 1/4" jacks, one is for a hold (sustain) pedal and the other is for portamento on/off, the portamento time is ajustable by a pot mounted on the side. The circuit also incorporates a bridge rectifier and volatage regulator, so it can be powered by anything from 9v to 30v AC or DC and is not polarity sensitive.