Unicorn HAT HD MIDI fiddling. Using raw MIDI read from Python.

midi.py

import unicornhathd
import time
from threading import Thread
import colorsys

MIDI_NOTE_OFF = 0x80
MIDI_NOTE_ON = 0x90
MIDI_AFTERTOUCH = 0xA0
MIDI_CC = 0xB0
MIDI_PATCH = 0xC0
MIDI_PRESSURE = 0xD0
MIDI_PITCH = 0xE0

hues = [0 for _ in range(8)]
bars = [0 for _ in range(8)]
pads = [0 for _ in range(8)]

def display_update():
    while running:
        for x in range(16):
            bar = x >> 1
            hue = hues[bar]
            r, g, b = [int(c * 255) for c in colorsys.hsv_to_rgb(hue, 1.0, 1.0)]
            velocity = bars[bar] / 8.0
            pad = pads[bar] / 8.0
            for y in range(16):
                if pad > y and x % 2 == 1:
                    if int(pad) == y:
                        br = pad - int(pad)
                        unicornhathd.set_pixel(x,y,r * br, g * br, b * br)
                    else:
                        unicornhathd.set_pixel(x,y,r, g, b)
                elif velocity > y and x % 2 == 0:
                    if int(velocity) == y:
                        br = velocity - int(velocity)
                        unicornhathd.set_pixel(x,y,r * br, g * br, b * br)
                    else:
                        unicornhathd.set_pixel(x,y,r, g, b)
                else:
                    unicornhathd.set_pixel(x, y, 0, 0, 0)

        unicornhathd.show()
        time.sleep(1.0 / 60)
        for bar in range(8):
            if pads[bar] > 0:
                pads[bar] -= 1

running = True
_t = Thread(target=display_update)
_t.daemon = True
_t.start()

with open("/dev/midi1","rb") as midi:
    while True:
        command = midi.read(1)
        command = ord(command)
        if command == MIDI_NOTE_OFF:
            key = ord(midi.read(1)) - 36
            velocity = ord(midi.read(1))
            print("NOTE OFF: {} {}".format(key, velocity))
            continue
        if command == MIDI_NOTE_ON:
            key = ord(midi.read(1)) - 36
            velocity = ord(midi.read(1))
            pads[key] = velocity
            print("NOTE ON: {} {}".format(key, velocity))
            continue
        if command == MIDI_CC:
            cc = ord(midi.read(1))
            value = ord(midi.read(1))
            hues[cc - 1] = value / 127.0
            bars[cc - 1] = value
            print("CC: {} {}".format(cc, value))

running = False
_t.join()

This is a quick and dirty script that just reads MIDI data from a raw device a byte at a time and decodes into the relevant control types/parameters. It only deals with a subset of MIDI at the moment, so weird things may happen if you use anything but keys/continuous controls.

There are much better ways to deal with MIDI than this, this example just demonstrates how simple the protocol is if you want to get down and dirty with it.