MIDI Melodeon

The MIDI Melodeon encoder is capable of encoding the required momentary action, push to make, single pole single throw (SPST) switches to produce the equivalent MIDI note-on/note-off data commands. The encoded switches are wired via IN4148 diodes, see schematic circuit diagram. The design is based on a two row diatonic keyboard with 10+11 keys for the right hand and 8 keys for the left hand. This design is for a melodeon in G/D keys, and a melodeon in B/C keys but other keys could be encoded if required.

• The transmit MIDI channel (1-16) can be selected by a 4-way DIP switch. 
• The velocity byte is preset to the half of maximum value.
•  The keyboard encoder is 32-note polyphonic.
• The switches are defined  as in the Key to MIDI Note Number Chart.
• A wiring layout for the circuit is also available.
• A switch to operate the melodeon in push/pull modes

The Melodeon Encoder to MIDI Unit utilizes:

• 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, see Circuit Diagram
• 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, see layout diagram

The Melodeon Encoder to MIDI Unit requires:

• A 9v battery or equivalent DC power source
• Required external switches and associated diodes
• a switch for push/pull modes

TOM SCARFF
1 Martello Court
Portmarnock
Dublin
Ireland.

Email: tscarff@eircom.net