5. BitBotXL buzzer

5.1. Using the buzzer

The buzzer is on pin0.
It can be turned on using: pin0.write_digital(1).
It can be turned off using: pin0.write_digital(0).

To turn on the buzzer for a specific time, put in a sleep between turning it on and turning it off. The code below has a sleep of 1000ms, so that the buzzer is on for 1 sec.

from microbit import *

pin0.write_digital(1)
sleep(1000)
pin0.write_digital(0)

Tasks

  1. Write code to turn on the buzzer for half a second.

  2. Write code, using a for-loop, to make 3 half second buzzer sounds with 1 second between each of them.

5.2. Refactoring into a class

The class, class BitBotXLBuzzer(), is used to group the code related to the buzzer.
The code to drive the buzzer is placed in a function, buzz.
The function will have a parameter, duration, which sets the duration of the buzzer.
This should also simplify the buzzer use. e.g. buzz(1000).
Firstly, the code above is placed inside a function.
The sleep value is replaced with the duration variable.
The duration parameter is added to the definition line: def buzz(duration):.
The self parameter must be included first for a regular method in a class.
Instead of def buzz(duration):, def buzz(self, duration): is required.
class BitBotXLBuzzer():

    def buzz(self, duration):
        """Sound a buzz for duration milliseconds."""
        pin0.write_digital(1)
        sleep(duration)
        pin0.write_digital(0)

5.3. Using the class

class BitBotXLBuzzer
Set up the buggy’s buzzer for use.
Use buzzer = BitBotXL.BitBotXLBuzzer() to use the buggy’s buzzer.
The code below imports the BitBotXL module and sets up the buzzer.
from microbit import *
import BitBotXL


# setup the buzzer
buzzer = BitBotXL.BitBotXLBuzzer()

5.4. Using the buzz method

buzz(duration)

Activates the buzzer for the specified duration in milliseconds.

The code below, uses buzzer.buzz(duration) to make a buzz.
from microbit import *
import BitBotXL


# setup the buzzer
buzzer = BitBotXL.BitBotXLBuzzer()

buzzer.buzz(1000)

Tasks

  1. Write code using a while True loop to make a 500ms buzz every 2 seconds.

  2. Write code using a for-loop to make buzz sounds of 100, 200, 300 and 400ms separated by a 500ms sleep.