Traffic Lights


In this lesson students will program the micro:bit to control external devices to create a traffic light sequence for a pedestrian crossing in the UK. Students will learn the basics of how the traffic lights system works and therefore will improve their knowledge of road safety.


  • Learn how to program multiple external outputs with the micro:bit to work in conjunction and independently of each other.
  • Gain a basic understanding of the traffic light sequence for a pedestrian crossing in the UK.

Download the Code

MakeCode Editor

Click the button below to download the MakeCode editor code for this lesson. The hex file is contained in a zip folder.

Kindly refer to our download the code page for instructions on how to upload your code onto the micro:bit. Please use instructions set A.

This code can also be uploaded into the MakeCode editor.

Kit Required


Innovation Board


Bi Colour LED Red/Blue

Bi Colour LED Red/Green

Bi Colour LED Red/Yellow

- MicroUSB Cable
- 4 x Connector Cable


  1. Connect the micro:bit to the Innovation board via the edge connector.
  2. Connect the speaker to ADC1 using one of the connector cables. Connect the red/blue LED to ADC2, the red/yellow LED to ADC3 and the red/green LED to IO1 using the other connector cables.
  3. Connect the micro:bit to a computer via the microUSB cable.
  4. Go to the MakeCode website on your computer and open a new project.

Time to Code

What Will Happen

When the micro:bit is powered the red/green LED will show green. If button A is pressed then the traffic light sequence will begin. The green LED will turn off and the yellow LED will light up for 3 seconds before turning off. The red LED will then show show. At the same time the speaker will beep to simulate a pedestrian crossing. This will happen for 10 seconds before the sequence continues to yellow and finally back to green.

Taking it Further

  • Design a 3D model of a traffic light that in corporate the LED devices and the speaker.
  • Adjust the traffic light sequence to simulate traffic lights in other countries around the world.

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