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MIDI Melodeon


MIDI Melodeon

Melodion1.jpg (17264 bytes)


This is a design for a reedless MIDI Melodeon encoder. Some of the advantages of such an instrument are instant key changes, via MIDI, and the ability to practice with headphones (silently to the outside world).


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 design consists of the encoded switches wired via IN4148 diodes, see switches 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/C keys, G/D keys, and  in B/C keys but other keys could be encoded if required.



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PRICE:  €45.00



PRICE:  €45.00



PRICE:  €45.00





The Melodeon Encoder to MIDI Unit utilizes:

  • The MIDI channel is set to channel 1 for right hand 10 + 11 switches,
  • The MIDI channel is set to channel 2 for the Bass and channel 3 for the associated Chord for left hand 8 switches,
  • The velocity byte is preset to the maximum value.
  • A wiring layout for the circuit is also available.
  • An Arduino board including a suitable pre-programmed microcontroller,
  • A 2.1mm power socket, and associated power-on LED, 
  • A MIDI 5-pin DIN output socket,
  • The switches circuit schematic is available,



The Melodeon Encoder to MIDI Unit requires:


  • A 9v battery or equivalent DC power source
  • Required 29 external switches and associated diodes
  • A switch to operate the melodeon in push/pull modes




Circuit Schematic:

A circuit schematic of the Miduino Melodeon shows the switch connections. Note that for this project the 4-way DIL switch is not required. The circuit schematic for the MIDI Melodeon switches, and a wiring diagram  are also available.




MIDI Wiring:

The MIDI  OUT connection uses a  5-Pin 180 degree DIN sockets. Note that the MIDI wiring is polarised and the correct pins should be used. 


MIDI Channels:

The MIDI channel is set to channel 1 for right hand 10+ 11 switches. The MIDI channel is set to channel 2 for the Bass and channel 3 for the associated Chord for left hand 8 switches. These 3 MIDI channels can be assigned to different MIDI instrument sounds, if required.



The Push/Pull switch can be mounted at the rear of the unit and operated by the left or right thumb. It is designed so that when pushing the melodeon the Push/Pull switch should be pushed also. Whereas when the melodeon is pulled the Push/Pull switch is released. Alternatively a foot-pedal switch could be used if desired.


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. Leads from a battery can be inserted in the Gnd and Vin pin headers of the POWER connector. .


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.