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MIDI 16 Channel Duplicate Switches

MIDI 16 Channel Duplicate Switches


This unit provides the ability to send the single-channel MIDI output of a keyboard controller into a sort of "MIDI channel mixer/ muter" , where you have the ability (while on stage) to quickly change which channels (1-16) are duplicating the MIDI input signal. The unit also has a Panic switch to switch ALL notes off.



The unit has a row of 16 channel-Duplicate buttons. So for example, if you had 8 of the buttons selected, you would be transmitting notes on 8 channels. This is very handy for creating multi-instrument layer stacks of differing combinations on the fly while playing a MIDI sampler/synthesiser, which you can set up with a separate instrument on each of the 16 channels







PRICE:  €55.00



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The MIDI 16 Channel Duplicate Switches unit utilizes

  • An assembled, built and tested Arduino board including a suitable pre-programmed Atmega microcontroller,
  • A 2.1mm power socket, and associated LED, 
  • Select MIDI channel via toggle switches
  • A MIDI activity LED,
  • A power-on LED,
  • A 150mm wired MIDI 5-pin DIN input socket,
  • A 150mm wired MIDI 5-pin DIN output socket, 
  • 17 off 0.1" pin-terminal switch inputs, 
  • The circuit schematic is available,



The MIDI16 Channel Duplicate Switches also requires:

  • A 9v battery or equivalent DC power source,
  • 16 Toggle/SPST switches,
  • 1 Momentary Push-button switch (Panic switch)





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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.




Circuit Schematic Diagram:

The circuit schematic diagram shows the connections for the 16 toggle switches. The 16 toggle switches can be Single Pole Single Throw (SPST) or if you want to use the LEDs, via their series resistors, to show which switch/channel is operational then 16 Double Pole Single Throw (DPST) switches can be used. There is also a momentary action Panic Switch to switch Off all notes, if required.


MIDI Specification: 

When a MIDI Channel command ( Note On or Off, Control Change, Program Change etc.), for example, Volume, Sustain, Pitch-Bend or Modulation are received, on the MIDI Channels corresponding to the MIDI Channel switches, which are activated (ON), they are transmitted. Otherwise they are blocked and do not pass through.


When a MIDI 'Note-On' command is received, then MIDI 'Note-On' commands on the MIDI Channels corresponding to the MIDI Channel switches, which are activated (ON), are transmitted.


When a MIDI 'Note-Off' command is received, then  MIDI 'Note-off' commands on the MIDI channels corresponding to the MIDI Channel switches, which are activated (ON), are transmitted.


When a MIDI Channel switch is switched to mute a channel, then the 'All Notes Off' procedure is triggered only once, and only for this particular channel.


This prevents notes continuing to play if a switch is switched Off after receiving a 'Note-On' command, but before receiving the corresponding 'Note-Off' command.


The outputs will switch Off if a  MIDI 'Note-On' with a velocity of 00 is received. The unit also works in MIDI Running Status mode.




Panic Switch:

If the MIDI module  has MIDI note-on commands producing 'stuck' notes which drone on and on, then this switch will produce a series of 'All Notes Off' commands or individual 'Note Off' commands when the Panic switch is pressed, and switches all the notes off.


Because some older MIDI machines do not respond to the 'All Notes Off' command there are 2 modes of operation.


When the momentary action switch  is operated the MIDI panic unit first produces the 'All Notes Off' MIDI command on all 16 MIDI channels. These commands take approximately 16 mS.


Secondly the unit produces a 'Note Off'  MIDI command on all notes (0-127) and on all 16 MIDI channels. These commands take approximately 2048 mS to transmit.


Power Supply:

The  Arduino and MIDI board can be powered via the USB connection or with an external power supply. The power source is selected automatically.


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.