Project Development Studio Midterm/Update

In light of the loss of fabrication resources I will be scaling down my project physically and focusing more on the design of a smaller prototype. To facilitate this I built a neotrellis m4 express kit. This is a common development board with drumpad made by Adafruit. Using this will allow me to take advantages of the work that has been done by Adafruit to quickly built different prototypes and experiment.

Mockup #1

Using some of the example sketches on the Trellis, there are RGB LED’s in each pad as well as programmable notes.

Their MIDIUSB sketch was actually very similar to what I was looking to do and served as a great test for many of the concepts for my design.

It uses a built-in accelerometer as well as midi notes to trigger sounds and effects. The X axis changes pitch bend up and down 1 semitone. The Y axis changes the modulation filter. Those two filters are the most common in most MIDI devices but I still often find the dials not very intuitive. Using the accelerometer felt more natural and fun. I will say that because of the small form factor of the trellis while the accelerometer of the movement felt natural, it then restricts you to two notes at a time. I want it to feel less like a gameboy and more like an expressive instrument.

Upside of using Trellis as development board:

Open source, many configurations to get inspired by, and a very fast board. This Trellis has a cortex m4 chip and built in micro usb ready to go. I can also use circuit python to code in python instead of using Arduino IDE because of the extra RAM on the board.

Downside of using Trellis as development board:

Limited mostly to using only Adafruit libraries, but this is also an upside as their documentation is quite good. The largest challenge I have is two fold- I want my final design in the future to be almost twice as big. The Trellis, while cute, is a little to small for a serious user. Also the accelerometer is better used while multiple notes can be played comfortably.

Moving forward

I will be working on restricting the movement of the trellis board by mounting it in an a 3D printed enclosure with springs. I want to mount the joystick for the pitch and modulation input as well. I will continue to tune the settings and get the most intuitive experience I can out of it. I will be presenting a song demo using the enclosed board.


Arduino vs Circuit Python: I have been coding in Arduino but I do have experience with Python and will likely give it a try this week.

3D Printing development:

The trellis has many online open source files and different enclosures I can use as starting points for my design.

Fully 3D printed enclosure? Or Lasercut plus acryllic housing?

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