MicroPython on the BBC micro:bit comes with a powerful music and sound module. It’s very easy to generate bleeps and bloops from the device by attaching a speaker or set of wired headphones.
If you are attaching a speaker, a passive piezo buzzer, or headphones, you can use crocodile clips to attach pin 0 and GND to the positive and negative inputs. It doesn’t matter which way round they are connected to a speaker, but a piezo buzzer may be polarized (check for a “+” marking the positive terminal).
Do not attempt this with an active Piezo buzzer - such buzzers are only able to play a single tone.
Let’s play some music:
import music music.play(music.NYAN)
Notice that we import the
music module. It contains methods used to make
and control sound.
MicroPython has quite a lot of built-in melodies. Here’s a complete list:
Take the example code and change the melody. Which one is your favourite? How would you use such tunes as signals or cues?
Wolfgang Amadeus Microbit¶
Creating your own tunes is easy!
Each note has a name (like
F), an octave (telling MicroPython how
high or low the note should be played) and a duration (how
long it lasts through time). Octaves are indicated by a number ~ 0 is the
lowest octave, 4 contains middle C and 8 is about as high as you’ll ever need
unless you’re making music for dogs. Durations are also expressed as numbers.
The higher the value of the duration the longer it will last. Such
values are related to each other - for instance, a duration of
4 will last
twice as long as a duration
2 (and so on). If you use the note name
then MicroPython will play a rest (i.e. silence) for the specified duration.
Each note is expressed as a string of characters like this:
"A1:4" refers to the note named
A in octave number
to be played for a duration of
Make a list of notes to create a melody (it’s equivalent to creating an animation with a list of images). For example, here’s how to make MicroPython play opening of “Frere Jaques”:
import music tune = ["C4:4", "D4:4", "E4:4", "C4:4", "C4:4", "D4:4", "E4:4", "C4:4", "E4:4", "F4:4", "G4:8", "E4:4", "F4:4", "G4:8"] music.play(tune)
MicroPython helps you to simplify such melodies. It’ll remember the octave and duration values until you next change them. As a result, the example above can be re-written as:
import music tune = ["C4:4", "D", "E", "C", "C", "D", "E", "C", "E", "F", "G:8", "E:4", "F", "G:8"] music.play(tune)
Notice how the octave and duration values only change when they have to. It’s a lot less typing and simpler to read.
MicroPython lets you make tones that are not musical notes. For example, here’s how to create a Police siren effect:
import music while True: for freq in range(880, 1760, 16): music.pitch(freq, 6) for freq in range(1760, 880, -16): music.pitch(freq, 6)
Notice how the
music.pitch method is used in this instance. It expects a
frequency. For example, the frequency of
440 is the same as a concert
used to tune a symphony orchestra.
In the example above the
range function is used to generate ranges of
numeric values. These numbers are used to define the pitch of the tone. The
three arguments for the
range function are the start value, end value and
step size. Therefore, the first use of
range is saying, in English, “create
a range of numbers between 880 and 1760 in steps of 16”. The second use of
range is saying, “create a range of values between 1760 and 880 in steps of
-16”. This is how we get a range of frequencies that go up and down in pitch
like a siren.
Because the siren should last forever it’s wrapped in an infinite
Importantly, we have introduced a new sort of a loop inside the
for loop. In English it’s like saying, “for each item in some
collection, do some activity with it”. Specifically in the example above, it’s
saying, “for each frequency in the specified range of frequencies, play the
pitch of that frequency for 6 milliseconds”. Notice how the thing to do for
each item in a for loop is indented (as discussed earlier) so Python knows
exactly which code to run to handle the individual items.