Build your own MIDI circuits
Frequently Asked Questions.
MIDI & Music
MIDI and Music Information
MIDI Program Change 1 to 128



The MIDI Program Change Commands can change the sound/voice in a MIDI sound module/synthesiser. There are 4 momentary action switches which can work in parallel with momentary action foot-pedals. 


An advantage of using Program Change data, instead of Note on/off commands,  is that you can interface with a lot of MIDI controlled effects units.


The 4 switches can increment/decrement the Program Change value, from 1 to 128, in steps of +1, -1, +10  or -10.  


The MIDI signal is also looped from the MIDI IN socket to the MIDI OUT socket so data can be looped through a number of other MIDI units.



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PRICE:  €50.00



The MIDI  Program Change unit utilizes:

  • An assembled, built and tested Arduino board including a suitable pre-programmed Atmega168,
  • A 2.1mm power socket, and associated LED, 
  • A MIDI detection LED,
  • A 4-way DIP switch, which selects the MIDI channel at power-on, shown in table 1
  • A 150mm wired MIDI 5-pin DIN input socket,
  • A 150mm wired MIDI 5-pin DIN output socket, 
  • A MIDI activity LED,
  • 4 off 0.1" pin-terminal switch inputs,
  • 4 off 0.1" pin-terminal Led outputs,
  • The circuit schematic is available,


The MIDI Program Change unit requires:

  • A 9 Volt battery or equivalent 9 Volt DC power source
  • 4  momentary action switches,
  • 4 Leds





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








Power Supply:

The  Arduino can be powered via the USB connection or with an external power supply. The power input selection (USB/EXT.) is automatically selected.


External (non-USB) power can come either from an AC-to-DC adapter (wall-wart) 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. A low dropout regulator provides improved energy efficiency.


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.




DIP Switch Selections



4 3 2 1
on on on on 1
on on on off 2
on  on  off on 3
on on off off 4
on off on on 5
on off on off 6
on off off on 7
on off off off 8
off on on on 9
off on on off 10
off on  off on 11
off on off off 12
off off on on 13
off off on off 14
off off off on 15
off off off off 16

Table 1 MIDI Channel