This whole project started when, after hearing the name for a long time, actually realised what an Arduino micro-processor could actually do. A short investigation lead to the discovery that lots of people were creating MIDI controllers using these controllers and that is was a fairly straight-forward thing to do.

The huge number of Arduino boards available was initially a little overwhelming, but on narrowing down what I actually wanted the STJORN controller to do a clear choice rose above the usual UNOs, Leonardos, etc.

The choice was a PJRC Teensy 3.2.

This tiny tiny board had everything I required for this project:

• Tonnes of digital inputs for footswitches (34 inputs to be precise)
• Plenty of analog inputs so I could use external expression pedals
• Built in, ready-to-go, USB MIDI 
  
  • This was probably one of the main reasons for choosing the Teensy to be honest
• Plenty of processing horsepower so that I didn't need to really worry about it
• i2c and SPI 
• Very small form factor
• Cheap! (around £18 in the UK)

One was purchased and within hours of really using an Arduino controller for the first time, I was already able to send and receive MIDI over USB!

I now have two Teensy 3.2s - one is on a breadboard and is used for testing circuits and generally playing around, and the other is for the STJORN itself.

For the board to be mounted in the STJORN, I have used a Tall Dog Teensy 3.2 Breakout to mount it. This not only provides easy access to all of the pins - some of which on the Teensy 3.2 board are located underneath with no direct access - but also some handy mounting holes to attach the board to the chassis. Here is the - actual one to be used in STJORN - Teensy 3.2 mounted to the breakout:

This little workhorse is going to do perfectly for this project.