micro:bit - Events

Events

All programs need a beginning.

Events trigger a stack of instructions (the code inside them).

  • The "On Start" event will start as soon as the micro:bit is switched on (or reset).
  • The "Forever" event will start as soon as any other event has finished. If there are no other events it will start as soon as the micro:bit is switched on (or reset).
  • The "On button 'A' pressed" event will start when the A button is pressed. You can change the button to 'B' or when 'A + B' are pressed at the same time.
  • The "On 'shake'" event will start when the micro:bit is shaken. This will make use of the Accelerometer!

This example shows how the micro:bit can have multiple events.

When the program starts it displays the text string "Hello World!".

It then shows a smiley face forever.

When the A button is pressed it displays the letter 'A'.

When the B button is pressed it displays the letter 'B'.

When the micro:bit is shaken it shows a sick face!

The purple input events will interrupt the 'forever' event, but not the 'on start' event.

Challenges

  • Write a simple program that will show a message when you press the A button.
  • Write a simple program that will show a different message when you shake the micro:bit.

Key Words

Event

An action that can trigger stack of code in a computer program. Events could happen at any time.

Input

Data that is entered into a computer system, this can be manually or by using sensors.

Accelerometer

A sensor that detects changes in acceleration. It is used to detect movement. You will find accelerometers in smartphones and game controllers (like the controllers for the Nintendo Switch).