BBC micro:bit mood feedback

mood.py

from microbit import *


def blink(img):
    for i in range(5):
        display.show(img)
        sleep(200)
        display.clear()
        sleep(200)


def increase_while_pressed(buttons, img):
    """Increase the brightness of the image while buttons are pressed.
    
    If the brightness reaches its maximum, return True. If the buttons
    are released before, return False.
    """
    brightness = 0.1
    step = 0.001  # Don't increase too fast.
    while all([button.is_pressed() for button in buttons]):
        brightness += step
        display.show(img * brightness)
        if brightness >= 1:
            return True
    return False

while True:
    sleep(200)  # Need some time to detect a double button press.
    buttons = []
    img = None
    if button_a.is_pressed() and button_b.is_pressed():
        buttons = [button_a, button_b]
        img = Image.MEH
    elif button_a.is_pressed():
        buttons = [button_a]
        img = Image.SAD
    elif button_b.is_pressed():
        buttons = [button_b]
        img = Image.HAPPY
    if buttons and img:
        if increase_while_pressed(buttons, img):
            blink(img)  # User feedback: choice confirmed.
    display.clear()