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MIDI Bass to Drum Trigger


MIDI Bass to Drum Trigger


The MIDI Bass to Drum Trigger unit is capable of converting the MIDI output from a Bass synthesiser/pedals  to produce a pulse with a variable voltage and variable width, which can be used to trigger a Drum module via its piezo trigger inputs.


The amplitude of the pulse can be varied from 0 to +5 Volts and the width (time) of the pulse can be varied from 2 micro-seconds(us) to 2 milli-seconds(ms).


The purpose of the unit is to provide a backing drum sound which is in time with a MIDI  Bass line, effectively providing a more interesting metronome sound.


The design can be bought as an assembled unit.





MIDI Bass to Drum Trigger Assembled


PRICE:  €50.00






The MIDI Bass to Drum Trigger Assembled utilizes:

  • An Arduino including a suitable pre-programmed Atmega168,
  • An Arduino MIDI IN/OUT assembled unit,
  • A 2.1m socket or USB socket for power,, 
  • A MIDI 5-pin DIN Input socket,
  • A MIDI 5-pin DIN Output socket,
  • The circuit schematic is available,
  • The transmit MIDI channel (1-16) can be selected by a 4-way DIP switch. .



The MIDI Bass to Drum Trigger units also require:

  • A 9v battery or equivalent DC power source,
  • 2 variable 10k linear potentiometer,
  • A jack-socket (if required).





The circuit has two 10k ohm potentiometers.  One controls the amplitude  of the pulse output from Pin D8 on the Miduino/Arduino, and the other controls the voltage fed to Analog Pin A0 of the Miduino/Arduino. This voltage is converted to a corresponding pulse width ranging from 2 micro-seconds(us) to 2 milli-seconds(ms).

At power-on the DIP switch positions are read and the unit will operate in a MIDI channel as shown in Table 1.





     *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.






MIDI Bass to Drum Trigger Circuit Schematic:

A circuit schematic of the MIDI Bass to Drum trigger unit shows the Pin numbers for the potentiometer connections. 


midi_boarduino_PINS_wiring.jpg (191151 bytes)


MIDI Bass to Drum Trigger 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. 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.



 MIDI Bass to Drum Trigger Circuit Schematic:

A circuit schematic and the wiring diagram of the MIDI IN and OUT circuit shows the Input/Output connections. The pin connections on the Arduino are also available.






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