MTAL – 6-output MIDI to Trigger module

MTAL – compact 6-output MIDI to Trigger interface with Accent and Learn features in 4hp eurorack modular format.


  • 6 assignable trigger outputs, 0 – +5V.
  • MIDI IN/ MIDI out via 3.5mm jacks.
  • 3 accent outputs (8 accent levels driven by note velocity)
  • 6 manual trigger buttons
  • Learn button
  • Led indicators (MIDI IN LED, OUTPUT trigger LED)
  • Interaction with CV/GATE bus Open source firmware*
  • Expandable**
  • DIY friendly
  • Dimensions: 4hp (128.4mm x 20mm)
  • Depth: 48mm (DIY-friendly through-hole version).
  • Weight: 65g (module only)
  • Power consumption: 30mA @ +12V


  • Receive MIDI note events on a pre-selected MIDI Channel (by default MIDI Channel 10).
  • Recognize 6 note values (by default starting at #24 C1) and generate positive 5V 10ms pulse when a trigger note is received.
  • Detect LEARN switch press and if a MIDI note event is received while it is pressed, assume the event’s MIDI Channel and subsequent notes as triggers.
  • Holding down LEARN switch for 10+ seconds without any MIDI Events received resets all device settings to defaults.
  • Booting up with the LEARN switch down starts unit in firmware update mode in which firmware can be updated by a SysEx Message.
  • Persist MIDI receive channel and trigger note values in non-volatile memory.
  • Soft MIDI THRU output — pass MIDI Events on all other channels to MIDI OUT.
  • MIDI IN LED, OUTPUT trigger LED.
  • 6 trigger switches.
  • 8 level accent (3 port pins).

Learn feature

Hold down LEARN switch and press 6 notes to remember as drum triggers then release the switch.

Reset to defaults

Hold down LEARN switch for 10+ seconds. The output trigger LED will shortly blink every second counting to 10, then blink rapidly three times to confirm firmware reset.

MTAL side view  - through hole version

Schematics: MTAL_v.00a_sch.pdf
BOM: in progress
Build guide: in progress

*MTAL based on midi2trigger project by Peter Kvitek