BlinkMs working in CircuitPython

blinkm_simple_demo.py

# blinkm_simple_demo.py -- very simply demonstrate low-level BlinkM control
# 4 Jan 2023 - @todbot / Tod Kurt
#
# Note: BlinkMs are designed to be 5V devices, they may not work on 3.3V systems.
#       You should really use a I2C level shifter like: https://www.adafruit.com/product/5637
#       If you're powering many BlinkMs or a BlinkM MaxM, you *definitely* need a level shifter,
#       since you cannot risk sending 5V back to the 3.3V inputs of a CircuitPython board.
#
# Details of BlinkM protocol at http://thingm.com/s/BlinkM_datasheet.pdf
#

import time
import board
import rainbowio

i2c = board.I2C()

# Lock the I2C device before we use it
while not i2c.try_lock():
    pass

# Print addresses found
device_addrs = i2c.scan()
print("I2C addresses found:", [hex(addr) for addr in device_addrs])
# Hopefully found one
if len(device_addrs) == 0:
    print("no devices!?")

# Assume first addr is blinkm
blinkm_addr = device_addrs[0]

# Do standard BlinkM setup
print("stop built-in script playing")
i2c.writeto(blinkm_addr, bytearray([ord('o'), 0x0]) )
print("set fadespeed to our liking")
i2c.writeto(blinkm_addr, bytearray([ord('f'), 0x10]) )

print("setting blinkm to black")
i2c.writeto(blinkm_addr, bytearray([ord('c'), 0x00,0x00,0x00]) )
time.sleep(1)  # wait a bit for dramatic effect

# Do a loop of happy disco colors
while True:
    c = rainbowio.colorwheel( (time.monotonic()*10000) % 255 )
    r,g,b = (c>>16 & 0xff), (c>>8 & 0xff), (c>>0 & 0xff) # convert 24-bit number to r,g,b
    print("setting color to %02x%02x%02x" % (r,g,b))
    i2c.writeto(blinkm_addr, bytearray([ord('c'), r,g,b ]) )
    time.sleep(0.2)

Small demo video of the above script

blinkm_circuitpython.mp4