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MIDI 48+48 Note Concertina with Pressure Sensor

 

MIDI 96 Switch Inputs Concertina

This is a design for a modified reed-less MIDI 96 (48+48) input switch Concertina. 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 modified MIDI Concertina encoder is capable of encoding the required 96 momentary action, push to make, single pole single throw (SPST) switches to produce the equivalent MIDI note-on/note-off data commands. 

  

 The design is based on a two sided  keyboard with 48 keys for the Left hand and 48 keys for the Right hand.  Other key arrangements could be encoded if required.

 


 

  

 

 

MIDI CONCERTINA 48+48

ITEM#: MIDICONT48+48

PRICE:  €75.00


 

       *Click to Enlarge*

  


  

The Modified Concertina Encoder to MIDI Unit provides:

  • An Arduino Mega 2560 board with a suitable pre-programmed microcontroller,
  • 48 Switch inputs for the Left Hand arranged in a 6x8 matrix and sending MIDI Out on Channel 1,
  • 48 Switch inputs for the Right Hand arranged in a 6x8 matrix and sending MIDI Out on Channel 2 for the notes, and sending MIDI Out on Channel 3 for the chords,
  • 2 momentary action switch inputs for Octave +1 and Octave -1,
  • 1 toggle switch input to switch between a fixed MIDI Volume output and a variable pressure sensor bellows output,
  • The velocity byte is preset a value of 100,
  • 1 input for the variable pressure sensor,
  • 1 variable pressure sensor type BMP180 or similar,
  • A 2.1mm power socket, and associated LED, 
  • A 150mm wired MIDI 5-pin DIN output socket,
 

 

  

The Modified Concertina Encoder to MIDI Unit requires:

  • A 9v battery or equivalent DC power source,
  • Required 96 external switches and associated diodes,  
  • 2 momentary action switches for Octave +1 and Octave -1,
  • 1 toggle switch input to switch between a fixed MIDI Volume output and a variable pressure sensor bellows output.
 

 

Circuit Schematic and Layout Drawings:

 

 


 

        

MIDI Wiring:

The MIDI IN and OUT connections use 5-Pin 180 degree DIN sockets. Note that the MIDI wiring is polarised and the correct pins should be used. 

  

MIDI Concertina Wiring:

The switches are organized in two  8 x 6 matrix (48 switches) arrangement. The switch keys are wired as shown in the  Wiring diagram.

 

 

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.