4. Radio advanced examples

4.1. Firefly

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


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

# The radio won't work unless it's switched on.
radio.on()

# Event loop.
while True:
    # the A-button sends a "flash" message.
    if button_a.was_pressed():
        radio.send('flash')  # a-ha
    # 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')  # a-ha

---

4.2. Send Drawn Image

from microbit import *
import radio


x = 2
y = 2
tick = -1

grid = [
    [0,0,0,0,0],
    [0,0,0,0,0],
    [0,0,0,0,0],
    [0,0,0,0,0],
    [0,0,0,0,0]
    ]


def Toggle(tx, ty):
    # bitwise or swaps 0 for 1 and 1 for 0
    grid[tx][ty] ^= 1


def Draw(t):
    img = Image('00000:'*5)
    for cy in range(0,5):
        for cx in range(0,5):
            img.set_pixel(cx, cy, grid[cx][cy]*5)
    img.set_pixel(x, y, (t % 2)*9)
    return img


def ImageString():
    s = ""
    for cy in range(0,5):
        for cx in range(0,5):
            s += str(grid[cx][cy]*9)
        s += ":"
    return s

radio.on()

while True:
    tick +=1
    if tick==2:
        tick = 0
    # check for movement
    dx = accelerometer.get_x()
    dy = accelerometer.get_y()
    if dx > 300:
        x += 1
        sleep(200)
    if dx < -300:
        x -= 1
        sleep(200)
    if dy > 300:
        y += 1
        sleep(200)
    if dy < -300:
        y -= 1
        sleep(200)
    # keep on grid
    x = max(0, min(x, 4))
    y = max(0, min(y, 4))
    # check for button press
    if button_a.was_pressed():
        Toggle(x, y)
        sleep(200)
    # update screen
    i = Draw(tick)
    display.show(i)
    if button_b.was_pressed():
        radio.send(ImageString())
    sleep(50)

from microbit import *
import radio

radio.on()

while True:
    s = radio.receive()
    if s is not None:
        print(s)
        i = Image(s)
        display.show(i)