This MIDI Bass Pedal Encoder circuit is capable of encoding up to 32 momentary action, push to make, single pole single throw (SPST), switches to produce the equivalent MIDI note-on/note-off data commands. So this design can be used with any 13 to 32 note pedalboards. Any unrequired notes can just be left unconnected. There are also Octave Up and and Octave Down switch inputs.Operation:
One side of each of the encoded Bass Pedal switches are wired to a common Ground (GND) pin and the other side of the switches 1 to 32 are wired to the digital input pins 22 to 53, respectively. The MIDI start Note is set to C2 (MIDI Note 36), which is connected to switch SW1, then the switches follow continuously to the last switch SW32, which is G4 (MIDI Note 67). But any different start note can be pre-programmed if required.
This unit can work in standard MIDI mode and via the USB connection, at the same time. It defaults to standard MIDI Baud rate of 31250. By replacing the original firmware on Mega8u2/16U2, the Arduino will act as USB-MIDI device (Standard Midi Class), you do not need to install additional device drivers on Windows, MaxOSX, and Linux, as the firmware acts as a device of Standard Midi Class. It will automatically install on the system as an Audio USB Device.Power Supply:
External power can come either from an AC-to-DC adapter or battery. The adapter can be connected by plugging a 2.1mm center-positive plug into the board's power jack.
The board can operate on an external supply of 7 to 20 volts. If supplied with less than 7V, however, the 5V pin may supply less than five volts and the board may be unstable. If using more than 12V, the voltage regulator may overheat and damage the board. The recommended range is 7 to 12 volts.