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Audio 11-Way Switcher for 8 MIDI Control Changes

Switcher for 8 MIDI Control Changes


A MIDI device (VoodooLab's GCX Audio Switcher) that can be controlled via 8 midi CC messages (controllers #80-#87 or #104-#111), where a data value of 0 is off, and 127 is on (like most effects units control the on-off status of several effects). The device listens to channel 16.

The MIDI Channel can be selected with a 4-way DIP switch. The device stores different sets of those 8 controllers along with their corresponding values (0/127) so you can use them as presets, 
that would respond to your foot-controllers messages.



*Click to Enlarge*




PRICE:  €50.00








The Switcher for 8 MIDI Control 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, 
  • 2 off 6-way Male Header pins,
  • 1 off 8-way Male Header pins,
  • 11 off 0.1" pin-terminal switch inputs,
  • The switches circuit schematic is available,
  • The MIDI IN/OUT circuit schematic is also available.



The Switcher for 8 MIDI Control Change requires:

  • A 9 Volt battery or equivalent 9 Volt DC external power source, or USB Connector.
  • 11 momentary action switches or footswitches






     *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:

A circuit schematic of the Switcher for 8 MIDI Control Change shows the Input Switch connections. Also a detailed switches schematic is also available.


midi_boarduino_PINS_wiring.jpg (191151 bytes) Circuit Pins Wiring



Power Supply:

The  Arduino/Freeduino etc. Diecimila can be powered via the USB connection or with an external power supply. The power source is selected by the PWR_SEL jumper. To power the board from the USB connection, place it on the two pins closest to the USB connector, for an external power supply, the two pins closest to the external power jack.


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.


Note that with the Arduino Duemilanove or Mega the power input selection (USB/EXT.) is automatically selected.



Note, because the MIDI IN Opto-coupler shares the same serial input as the USB interface, if re- programming the Arduino the MIDI IN connection has to be disconnected.



The MIDI unit can be combined/expanded by connecting the MIDI OUT of one unit to the MIDI IN of the following unit.




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