Micro:bit 2-way radio example - adding audio alerts

This post adds onto the previous tutorial, so if you haven’t already, you shoud go have a look at that first.

Adding sound alerts

If you’ve got a speaker connected to your Micro:bit, or have the MI:Power battery add-on that includes a speaker, it’s easy to add a sound to alert us of sending or receiving a new emoticon.

In the original code, we had an if statement that would display the TARGET image, pause, and then display whatever image the incoming index pointed to:

    # If there's incoming data, show the emoticon that's been received
    if incoming:
        display.show(Image.TARGET)
        sleep(500)
        display.show(images[int(incoming)])
        sleep(2000)

Let’s change that to play a couple of short notes, when we detect an incoming radio message. First we’ll have to import the music functions for the Micro:bit. So, just after the existing import radio statement, at the top of the code, add the following import:

import music

Now look for the if incoming: code and find the following two lines:

        display.show(Image.TARGET)
        sleep(500)

To play two notes instead of displaying the target and waiting, modify the code as follows:

    if incoming:
        music.play(["C4:2","D4:5"])
        #display.show(incoming)
        display.show(images[int(incoming)])
        sleep(

Save the Python code and send it to the Micro:bit. When it receives a message (emoticon), you’ll hear it play the two notes and immediately display the emoticon sent.

The information for the notes are simply stored in a dictionary i.e. a list of pairs, known as tuples, in the format NOTE:DURATION. Because it’s a dictionary, we put our NOTE:DURATION pairs inside square brackets, separated by commas.

Additionally, if you’d like to play some notes when sending an emoticon, you can find the line that checks for both buttons pressed:

    if button_a.is_pressed() and button_b.is_pressed():

Now place a similar music.play() line after it. To make sure it’s within the if statement, remember to indent it. Now when you write this code to the Micro:bit, you’ll have sound alerts when you send and receive emoticons.

If those tones aren’t to your liking, you can also use speech.

For more information on creating sound on the Micro:bit you can find the documentation here.