Blackberry Trackball (ICSH044A) driver for Adafruit QtPY/Raspberry Pico. See https://developer.run/63 for context

trackball.py

# Need to install adafruit_debouncer an adafruit_hid

import digitalio
import board
import time
import usb_hid
from adafruit_debouncer import Debouncer
from adafruit_hid.mouse import Mouse
import time

def setup(pin):
  inp = digitalio.DigitalInOut(pin)
  inp.direction = digitalio.Direction.INPUT
  inp.pull = digitalio.Pull.UP
  return Debouncer(inp, interval=0.0001)

step = 4
smooth = 8
accel = 2
max_accel = 5

def move(last):
    now = time.time()
    multiplier = max_accel+1+max(last-now,-max_accel)
    return multiplier*accel*step, now

mouse = Mouse(usb_hid.devices)

# Raspberry Pico
# up = setup(board.GP3)
# down = setup(board.GP2)
# left = setup(board.GP4)
# right = setup(board.GP5)

# Adafruit QtPY
up = setup(board.A0)
down = setup(board.A1)
left = setup(board.A2)
right = setup(board.A3)

up_upd = time.time()
down_upd = time.time()
left_upd = time.time()
right_upd = time.time()

x=0
y=0

while True:

    up.update()
    if up.fell:
        mv,up_upd=move(up_upd)
        if y>0:
            y=-mv
        else:
            y-=mv
    else:
        down.update()
        if down.fell:
            mv,down_upd=move(down_upd)
            if y<0:
                y=mv
            else:
                y+=mv

    left.update()
    if left.fell:
        mv,left_upd=move(left_upd)
        if x<0:
            x=mv
        else:
            x+=mv
    else:
        right.update()
        if right.fell:
            mv,right_upd=move(right_upd)
            if x>0:
                x=-mv
            else:
                x-=mv

    mvx = 0
    mvy = 0
    if (x>0):
        x=max(0, x-smooth)
        mvx = smooth
    elif (x<0):
        x=min(0, x+smooth)
        mvx = -smooth

    if (y>0):
        y=max(0, y-smooth)
        mvy = smooth
    elif (y<0):
        y=min(0,y+smooth)
        mvy = -smooth

    if not mvx == 0 or not mvy == 0:
        mouse.move(x=mvx, y=mvy)