MIDI BASS PEDAL UNIT

Nowadays MIDI devices come in all shapes and forms and MIDI controllers range from standard keyboards to various trigger devices. While most MIDI triggers are controlled by hand some people like to use their feet also, allowing a guitarist or keyboard player to add bass or trigger drums or other MIDI sources, while simultaneously playing their instrument by hand. A number of MIDI bass pedals have appeared on the market in the last few years but their price is in the hundreds of pounds range. So I decided to design and build my own bass pedal unit.

The MIDI Bass Pedal uses the MIDI keyboard encoder (MKE), which is capable of encoding any number of momentary action, push to make, single pole single throw (SPST), switches from 1 up to 128 to produce the equivalent MIDI note-on/note-off data commands. The encoded switches are wired via IN4148 diodes, see schematic circuit diagram. 

This unit can be connected to new bass pedals or it can be used with an older non-MIDI bass pedals by using magnetic/reed switches to isolate the old and new scanning circuits. This will allow the older bass pedal synthesizer to continue to operate as normal while also providing a MIDI output.

• The transmit MIDI channel (1-16) can be selected by a 4-way DIP switch. 
• The velocity byte is preset to half the maximum value.
•  The keyboard encoder is 32-note polyphonic.
• The switches, 0 to 127, are defined in the MIDI Note Number to Frequency Conversion Chart, so any note range can be selected,
• A wiring layout for the circuit is also available.

The MIDI Bass Pedal  Encoder to MIDI Unit consists of:

• A Printed Circuit Board (PCB), 
• A pre-programmed 16F877 PIC,
• The 4-way DIP switch which selects the MIDI transmit channel via DIP switches 1-4 (See Table 2) 
• A 9 volt battery connector
• A MIDI 5-pin DIN output socket, 
• A screw terminal connector for an external 9-12 volts DC supply and associated power-on LED,
• Three 8-way screw terminal connectors for connecting the external switches, 

The  MIDI Bass Pedal  Encoder to MIDI Unit  requires:

• A 9v battery or equivalent DC power source
• Required external switches and associated IN4148 diodes