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MIDI Treble, Tenor and Baritone Concertina


MIDI Treble, Tenor & Baritone Concertina

concertina_english_48.jpg (37695 bytes)


This is a design for a 48-Key reedless switchable MIDI Treble, Tenor and Baritone Concertina. So you can have 3 layout variations that can be selected, using 3 switches, by the user.  


There are also 2 transpose switches which can transpose any of the three concertina layouts by + 6 or - 6 semitones, in individual semitone steps.


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 Treble, Tenor and Baritone Concertina encoder is capable of encoding the required 48 momentary action, push to make, single pole single throw (SPST) switches, wired via IN4148 diodes, to produce the equivalent MIDI note-on/note-off data commands. 







MIDI Concertina 

Treble, Tenor and Baritone


PRICE:  €55.00


       *Click to Enlarge*


The Treble, Tenor and Baritone Concertina  Encoder to MIDI Unit utilizes:

  • The MIDI channel is set to channel 1 for left and right hand 24 + 24 switches,
  • The velocity byte is preset to the maximum value,
  • An Arduino board including a suitable pre-programmed microcontroller,
  • A 2.1mm power socket, and associated LED, 
  • A MIDI 5-pin DIN output socket,
  • The switches circuit schematic is available,
  • The Function Switches are available.



The Treble, Tenor and Baritone Concertina Encoder to MIDI Unit requires:

  • A 9v battery or equivalent DC power source,
  • Required 48 external switches and associated diodes, 
  • 3 Function Change switches and associated diodes,
  • 2 Transpose Change switches and associated diodes,
  • 1 MIDI Panic switch and associated diode.


Circuit Schematic:

A switches circuit schematic of the MIDI Treble, Tenor and Baritone Concertina shows the switch connections.  Also the circuit for the Function Change Switches inputs are available.




Hall Effect Wiring:

 You should use Unipolar Hall Effect devices and if you use Open Collector devices you will need a Pull-Up resistor for each device.








Concertina Keyboard Ranges:


The diagram below shows the Treble, Tenor and Baritone Concertina Keyboard ranges and their MIDI numbers.


*Click to Enlarge*


 The design is based on a two sided diatonic keyboard with 24+24 keys for the Left hand and for the Right hand. This design is for an English Concertina but other keys could be encoded if required.




Octave  Note Numbers
C C# D D# E F F# G G# A A# B
-1 0 1 2 3 4 5 6 7 8 9 10 11
0 12 13 14 15 16 17 18 19 20 21 22 23
1 24 25 26 27 28 29 30 31 32 33 34 35
2 36 37 38 39 40 41 42 43 44 45 46 47
3 48 49 50 51 52 53 54 55 56 57 58 59
4 60 61 62 63 64 65 66 67 68 69 70 71
5 72 73 74 75 76 77 78 79 80 81 82 83
6 84 85 86 87 88 89 90 91 92 93 94 95
7 96 97 98 99 100 101 102 103 104 105 106 107
8 108 109 110 111 112 113 114 115 116 117 118 119
9 120 121 122 123 124 125 126 127







MIDI Panic Switch input:

There is also a MIDI Panic Switch input which turns off all MIDI notes and so prevents notes to drone on. If you have a MIDI module that sometimes has MIDI note-on commands producing 'stuck' notes which drone on and on, then this circuit design will produce a series of 'All Notes Off' commands or individual 'Note Off' commands if the switch is pressed, and switches all the notes off.


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


So, for example, terminal connected to D10  is wired to one side of the 8 key switches SW 0 to SW7 and the wire can be looped from one key switch to the next. Also the other sides of these switches/diodes are connected down to Arduino contacts D2 to D9.


Each of the other side of these switches SW0 to SW7 is wired to a diode on the Cathode (K) side (end of diode with stripe).

The other side of each of these diodes is looped to 7 other diodes. For example Anode (A) of diode DO is looped to D8 then to D16 then to D24 etc. down to D40 and finally to digital terminal Pin D2 on the Arduino.


The rest of the wiring is done in a similar manner.


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.