MIDI Breath Controller
A low-cost homemade breath controller made with Arduino Pro Micro.
The MIDI (Musical Instrument Digital Interface) standard has been in use since the early 1980s. Fast forward 40-ish years, and the Arduino Pro Micro and other inexpensive microcontroller boards, makes it possible to build your own MIDI gadget with just a bit of tinkering. In this project, Andreas Mueller employs the ATmega32U4 board, along with an assortment of other hardware bits, to create a breath interface device.
Blowing to modify note characteristics, as demonstrated in the video below, seems to be quite natural. Of course, breath has been used for musical control since the advent of “analog” wind instruments thousands of years ago. In this case, however, Mueller is using a keyboard to dictate the notes being played, not physical notches or valves.
To read the user's breath, the setup includes a syringe with a BME280 pressure (and temperature/humidity) sensor inside, connected to the mouthpiece via a length of flexible tubing. The mouthpiece features a 3mm hole for the air to escape, allowing pressure to be dynamically controlled based on how hard the user is blowing at the time. The syringe’s plunger can be adjusted to change its volume, which in turn changes the system's responsiveness and required blowing force.
The Pro Micro reads the sensor's pressure output, and translates this into MIDI, via code available on the project writeup. It looks like a lot of fun, perhaps a testament to decades of MIDI development, plus wind instrument techniques perfected over millennia!