Arduino Drum Trigger to MIDI Shield PCB Build Guide

By Kevin on October 27, 2024

Here are the build notes for my Arduino Drum Trigger to MIDI Shield PCB.

Warning! I strongly recommend using old or second hand equipment for your experiments. I am not responsible for any damage to expensive instruments!

If you are new to Arduino, see the Getting Started pages.

Bill of Materials

Arduino Drum Trigger to MIDI Shield PCB (GitHub link below)
6x 2N3904 NPN transistors
6x 1N4148 small signal diodes
6x 1M resistors
6x 100K resistors
6x 10K resistors
2x 220Ω resistors
7x stereo TRS sockets (see photo for footprint)
Set of Arduino extended pin headers (1x 10 way, 2x 8 way, 1x 6 way)

Note that extended Arduino headers are recommended as they have longer legs which ensures that the TRS sockets will not get shorted out on the Arduino's USB socket or ICSP header.

If normal Arduino headers are used then steps must be taken to remove the possibilities of shorts once plugged in.

Build Steps

Taking a typical "low to high" soldering approach, this is the suggested order of assembly:

Diodes.
Resistors.
TRS sockets.
Transistors.
Arduino headers.

Here are some build photos.

The pads on the footprint for the transistors are quite close together, so care is needed to avoid shorts. I found it best to solder the middle pins first and then inspect with a magnifier after soldering.

Testing

I recommend performing the general tests described here: PCBs.

PCB Errata

There are the following issues with this PCB:

None at present.

Enhancements:

A MIDI disable option could be added (but doesn't appear necessary).

Find it on GitHub here.

Sample Applications

The following IO pins are used:

D2-D7: Trigger inputs
D1: MIDI output

Here are some applications to get started with:

Arduino Drum Trigger to MIDI.

Closing Thoughts

This seems to work really well paired with my Arduino Clock Generator Shield PCB.

Although this is described as a drum trigger to MIDI, naturally it could be used to create any set of MIDI messages on reception of up to six 5V trigger inputs.

Kevin