The Proximity Trinkey makes a terrific MIDI controller you can easily add to your laptop music setup!
USB MIDI sends either a CC (continuous controller) value from 0-127 based on proximity to a mod function of your choosing, or a pitchbend value from 8192-16383.
Setup
The APDS9960 library is already built into CircuitPython for the Proximity Trinkey, as are the NeoPixel, usb_midi, and touchio libraries. However, you'll need to manually load the MIDI and register libraries.
Click the Download Project Bundle button below to download the necessary library dependency and the code.py file in a zip file. Extract the contents of the zip file.
From inside the lib/ folder in the Project Bundle, copy the adafruit_register/ and adafruit_midi/ folders to the /lib folder on your CIRCUITPY drive.
Then, copy the code.py file to your CIRCUITPY drive.
Your CIRCUITPY drive contents should resemble the image.
You should have in / of the CIRCUITPY drive:
- code.py
And in the lib folder on your CIRCUITPY drive:
- adafruit_midi/
- adafruit_register/
NOTE: if you run out of space while copying the libraries to your CIRCUITPY drive, try using CircUp instead of the graphical UI of your operating system!
# SPDX-FileCopyrightText: 2021 John Park for Adafruit Industries
# SPDX-License-Identifier: MIT
"""
Proximity Trinkey MIDI
Touch pads switch between CC and Pitch Bend modes
Blue LED for CC, Red LED for pitchbend
Brightness of LEDs for proximity
"""
import board
import neopixel
import touchio
import usb_midi
import adafruit_midi
from adafruit_midi.control_change import ControlChange
from adafruit_midi.pitch_bend import PitchBend
from adafruit_apds9960.apds9960 import APDS9960
i2c = board.I2C() # uses board.SCL and board.SDA
# i2c = board.STEMMA_I2C() # For using the built-in STEMMA QT connector on a microcontroller
apds = APDS9960(i2c)
apds.enable_proximity = True
touch1 = touchio.TouchIn(board.TOUCH1)
touch2 = touchio.TouchIn(board.TOUCH2)
pixels = neopixel.NeoPixel(board.NEOPIXEL, 2)
midi = adafruit_midi.MIDI(
midi_in=usb_midi.ports[0], in_channel=0, midi_out=usb_midi.ports[1], out_channel=0
)
CC_NUM = 46 # pick your midi cc number here
def map_range(in_val, in_min, in_max, out_min, out_max):
return out_min + ((in_val - in_min) * (out_max - out_min) / (in_max - in_min))
pixels[0] = 0x000000
pixels[1] = 0x0000FF
prox_pitch = 8192
last_prox_pitch = prox_pitch
prox_cc = 0
last_prox_cc = prox_cc
prox_bright = 0
last_prox_bright = prox_bright
mode = True
while True:
if touch1.value: # CC mode
pixels[0] = 0xBB0000
pixels[1] = 0x0
mode = False
if touch2.value: # pitch bend mode
pixels[0] = 0x0
pixels[1] = 0x0000FF
mode = True
if mode:
prox_cc = int(map_range(apds.proximity, 0, 255, 0, 127))
if last_prox_cc is not prox_cc:
midi.send(ControlChange(CC_NUM, prox_cc ))
print("CC is", prox_cc)
last_prox_cc = prox_cc
else:
prox_pitch = int(map_range(apds.proximity, 0, 255, 8192, 16383))
if last_prox_pitch is not prox_pitch:
midi.send(PitchBend(prox_pitch))
print("Pitch bend is", prox_pitch)
last_prox_pitch = prox_pitch
prox_bright = map_range(apds.proximity, 0, 255, 0.01, 1.0)
pixels.brightness = prox_bright
Use It
To test the controller, plug it into your computer and launch this handy Chrome browser MIDI Monitor web app to check that it is working.
MIDI messages are fun to look at, but even better when the make some sound! Use a software synthesizer that accepts MIDI messages (pretty much all of them do!).
Here are some examples of free, open source synths for Linux, Windows, and mac os:
Launch your software synth and select the ProxLight Trinkey CircuitPython board as your MIDI source.
Then, assign MIDI CC 46 (you can edit the CircuitPython code.py file to pick a different MIDI CC number if you like) to a parameter and have fun!
Tap the cap switch pads to change to pitchbend mode and get all theremin-ish up in there.
