CircuitPython Trellis M4 pixel tilt drawing demo

tiltpixel.py

# Tiny slow gravitational etch-a-sketch. Press a button to reset.
# using https://github.com/adafruit/Adafruit_CircuitPython_TrellisM4
# and https://www.adafruit.com/product/4020

import time
import board
import busio
import adafruit_adxl34x
import adafruit_trellism4

trellis = adafruit_trellism4.TrellisM4Express()

color = (0, 0, 0)

# Our accelerometer
i2c = busio.I2C(board.ACCELEROMETER_SCL, board.ACCELEROMETER_SDA)
accelerometer = adafruit_adxl34x.ADXL345(i2c)

# map value from one range to another
def linmap(x, inx, iny, ox, oy):
    return ((x - inx) * (oy - ox) + ox * (iny - inx)) / (iny - inx)

class Dot:
    def __init__(self):
        self.lx = 4
        self.ly = 1
        self.x = 4.0
        self.y = 1.0
        self.drawn = False

    def update(self, tx, ty):
        self.vx = 0
        if abs(tx) > 2:
            self.vx = -1 if tx > 0 else 1

        self.vy = 0
        if abs(ty) > 2:
            self.vy = -1 if ty < 0 else 1

        self.x = self.x + self.vx
        self.y = self.y + self.vy

        # don't fall outside the boundaries
        if self.x < 0:
            self.x = 0
        if self.x > 7:
            self.x = 7

        if self.y < 0:
            self.y = 0
        if self.y > 3:
            self.y = 3

    def draw(self):
        x = int(self.x)
        y = int(self.y)

        # only redraw if the dot has moved
        if not self.drawn or self.lx != x or self.ly != y:
            trellis.pixels[self.lx, self.ly] = (0, 0, 10)
            trellis.pixels[x, y] = (100, 0, 0)

        self.lx = x
        self.ly = y
        self.drawn = True

c = Dot()

last_accel = 0
accel_gap  = 0.25 # time between updates

while True:
    tx = accelerometer.acceleration[1]
    ty = accelerometer.acceleration[0]
    tick = time.monotonic()

    if trellis.pressed_keys:
        trellis.pixels.fill(0)

    if tick > last_accel + accel_gap:
        c.update(tx, ty)
        c.draw()
        print("%0.3f %0.1f %0.1f" % (tick, tx, ty))
        last_accel = tick