MicroBit Magic 8 Ball with MicroPython

I wanted to create something with the MicroBit which used the on-board accelerometer and I settled on a Magic 8 Ball, the fortune-telling pool ball which when shaken and asked a question it provides, a, often cryptic, response.

The program works out whether the MicroBit has been shaken by:

• Reading the x, y, z values from the accelerometer in a loop and adding them together to get a total force exposed
• Getting the difference between the last reading and the current reading
• If the difference is greater than a threshold, you assume the MicroBit has been shaken

I wrapped this into a function wait_for_shake, which perhaps not unsurprisingly blocks until the MicroBit is shaken!

import microbit

TOLERANCE = 3000

def get_accel_total():
    x = microbit.accelerometer.get_x()
    y = microbit.accelerometer.get_y()
    z = microbit.accelerometer.get_z()
    return x + y + z

def wait_for_shake():
    shaken = False
    last = get_accel_total()
    while not shaken:
        this = get_accel_total()
        diff = last - this
        if diff < 0: diff = diff * -1
        if diff > TOLERANCE:
            shaken = True
        last = this
        microbit.sleep(50)

Its not 'very' sophisticated but it works.

Once I had this working it pretty simple to add a loop which waited for the MicroBit to be shaken and scrolled a random message on the LED screen.

MESSAGES = ["It is certain", "Dont count on it", "Ask again"]
while True:
    microbit.display.print("8")
    wait_for_shake()
    microbit.display.clear()
    microbit.sleep(2000)
    message = microbit.random(len(MESSAGES))
    microbit.display.scroll(MESSAGES[message])

If you want to add your own messages, just add them to the MESSAGES list.

You can find the code here and other examples in my microbit-micropython GitHub repository.