Build your own MIDI projects
Frequently Asked Questions.
MIDI & Music
MIDI and Music Information
MIDI 8 Channel Duplicate Switches

MIDI 8 Channel Duplicate Switches


This unit provides the ability to duplicate the MIDI data arriving on MIDI Channel 1 and transmit a copy of this data to output channels 2 to 8, if each of the corresponding channel switches are switched On. Otherwise, if any channel switch is Off, that channel's data is not transferred to the MIDI output.



  • Switch 1 will mute/active data in channel 1,
  • Switches 2-8 will mute/duplicate (from channel 1 even if channel 1 is muted),
  • If MIDI Channel data is coming in on channels 2 to 8, it is possible to mute it as well or merge it with duplicated data from channel 1.
  • If MIDI Channel data is coming in on channels 9 to 16, it is passed through.




So the unit can produce a multi-channel, multi-channel MIDI output from a single MIDI Input channel. So it acts as a sort of "MIDI channel Duplicater" , where you have the ability (while on stage) to quickly change which channels (1-8) are duplicating the MIDI input signal. 


The unit also has a Panic switch to switch All notes off. This design uses an Arduino Mini Pro board to reduce the physical size of the project.







PRICE:  €55.00



       *Click to Enlarge*







The MIDI 8 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 MIDI8 Channel Duplicate Switches also requires:

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





     *Click to Enlarge*

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 8 toggle switches. The 8 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 8 Double Pole Single Throw (DPST) switches can be used. There is also a momentary action Panic Switch to switch Off all notes, if required.


There is also a wiring diagram available.



*Click to Enlarge*




MIDI Specification: 

When a MIDI 'Note-On' command is received on Channel 1, 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 on Channel 1, 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 8 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 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.