Musical Microbits

Coding a micro:bit in Python

Open the new Python editor by visiting python.microbit.org/. Your screen will look something like this:

In the middle is where you will add your own code.
On the left-hand-side is the reference menu - you can see examples of some of the code here, as well as help understanding these examples.
On the right-hand-side is the simulator - a pretend micro:bit you can use to test your code.
On the bottom is the Send to Micro:bit button, which you will use to send code to your physical micro:bit.

Edit the code on the screen, then flash it to your micro:bit to see the changes.

Try:

Editing the image that is shown (hint: check the reference menu, under Display, for a list of images)
Changing the number in the brackets after sleep (hint: this tells the micro:bit how long to keep your image on the display)
Making the micro:bit scroll your name instead of 'Hello'

Using a button as an input

Currently, your code runs forever. The micro:bit accepts inputs - for example, you can choose to run code only when you press the micro:bit's A button.

Find the Buttons section of the Reference menu.

Drag-and-drop the if button_a.was_pressed(): example into your code, so that it looks like this:

while True:
    if button_a.was_pressed():
        display.scroll('A')
    display.show(Image.HEART)

Try running your code in the simulator. What should happen is:

If you press the A button, the letter 'A' scrolls across the display
Otherwise, your original code continues to run (forever)

Indentation is very important - this is the gap on the left in the code. It determines when sections of code are run.

To make all of the code run when you press button A, and nothing to happen if you don't, edit the indentation, to make your code look like this:

while True:
    if button_a.was_pressed():
        display.scroll('A')
        display.show(Image.HEART)

All of your code should line up neatly.

Does your code work the way you expect?

Challenge: can you make something different happen if you press button B?

Using a servo motor

You have added inputs, to control when your code will run. Now you are going to add a new output - a motor.

Edit your code, so that it looks like this:

while True:
    if button_a.was_pressed():
        pin1.write_analog(35)
        sleep(1000)
        pin1.write_analog(85)
        sleep(1000)

You can keep your original code in there as well if you like, but be careful of the indentation, and think about the order your code will run in.

What this new code does, is send a signal to pin1 of your micro:bit - one of the gold teeth on the bottom.

Give pin1 a value of 35
Wait for 1 second
Give pin1 a new value of 85
Wait for 1 second

Connect your motor to the micro:bit and see if your code works. Does your micro:bit wave to you?

photograph of a BBC micro:bit. A crocodile clip with a white wire is attached to the gold pin labelled 1, second from the left. A crocodile clip with a black wire is attached to gold pin labelled GND, furthest right.

Connect the battery
Attach the white crocodile clip to pin1
Attach the black crocodile clip to GND

For more details about this circuit, click here.

Challenge: You can make this code more efficient by using variables. Try setting a tempo variable, and using this inside sleep. You could even extend this further by letting the micro:bit randomly choose the tempo for you! For some help to implement this challenge, click here.

Using the speaker

Now we will add musical notes into the program - to start with, we'll time the notes to play whenever the servo motor moves.

Firstly, add this line above your while True loop:

import music

This line is needed to use the music note code.

Use this syntax to add a musical note:

music.play('c')

To add a 'C' when the servo moves one way, and a 'D' when it moves the other, the code would look like this:

while True:
    if button_a.was_pressed():
        pin1.write_analog(35)
        music.play('c')
        sleep(1000)
        pin1.write_analog(85)
        music.play('d')
        sleep(1000)

Challenge: to expand on this code, take a look in the Sounds section of the Reference menu. Could you make a list of notes to make a whole tune?

Adding an intrument

Now add a physical instrument for your servo motor to hit!

animated photo showing a servo motor ringing a windchime, the structure is make out of K'nex and the motor is secured with blue tack

To get your project working you will need to:

Choose or create a physical instrument.
Set the servo motor angles to get the best hit.
Secure the motor and the instrument, so you can play it consistently.

Challenge: Can you work with someone else to make an orchestra? Discuss your timings to make a good tune!