11. Radio Firefly

11.1. Firefly

This script essentially simulates a group of fireflies flashing in a random pattern, like you might see in nature.
Each microbit running this script acts like a firefly, flashing its LED display and occasionally causing other microbits in the same radio group to flash.
The randomness of the delays and re-broadcasts helps to create a natural, organic flashing pattern.

flash = [Image().invert()*(i/9) for i in range(9, -1, -1)] creates a list of images that represent different stages of a firefly’s flash.
Image().invert(): This creates an inverted image of the microbit’s LED display. Image() produces an image with all 25 LEDS at 0 brightness. The invert() function inverts the brightness of the LEDs, so they are all at maximum brightness (9).
*(i/9) multiplies the inverted image by a fraction. When i is 9 it gives 1. When i is 0 it gives 0.
for i in range(9, -1, -1): This is a loop that generates the numbers 9 down to 0. For each number i, it creates an image with brightness i/9, so the first image is at full brightness (9/9 = 1), and the last image is completely off (0/9 = 0).
The resulting flash list is a sequence of 10 images that represent a firefly’s flash fading out, from full brightness to off.
This list is used later in the script to display the flash animation on the microbit’s LED display.
The display.show(flash, delay=100, wait=False) line in the script displays each image in the flash list in sequence, with a delay of 100 milliseconds between each image, creating the flashing effect.

# A microbit Firefly.
# By Nicholas H. Tollervey. Released to the public domain.
from microbit import *
import radio
import random

# Choose the same group 0-255
radio.config(group=8)
# The radio won't work unless it's switched on.
radio.on()

# Create the "flash" animation frames
flash = [Image().invert()*(i/9) for i in range(9, -1, -1)]


# Event loop.
while True:
    # the A-button sends a "flash" message.
    if button_a.was_pressed():
        radio.send('flash')
    # Read any incoming messages.
    incoming = radio.receive()
    if incoming == 'flash':
        # If there's an incoming "flash" message display
        # the firefly flash animation after a random short pause.
        sleep(random.randint(50, 350))
        display.show(flash, delay=100, wait=False)
        # Randomly re-broadcast the flash message after a slight delay.
        if random.randint(0, 9) == 0:
            sleep(500)
            radio.send('flash')

Tasks

Modify the code above so that the re-broadcast occurs with a 1 in 5 chance by changing the randint arguments.
Modify the code above so that the re-broadcast occurs with a 1 in 2 chance by changing the randint arguments.
Modify the code above so that the flash lasts twice as long by changing the value of the delay.
Modify the code above so when the B-button is pressed, a series of 5 flash messages are sent over 2 seconds.
Replace the flash code with this code to flash an image of a butterfly flash = [Image.BUTTERFLY*(i/9) for i in range(9, -1, -1)]. Then vary the image used from a list of 4 images.