A Light Emitting Diode (LED) 

is an electrical component that lights up when a current is passed through it.

  • LEDs come in certain voltage ratings – you must use an LED with the correct voltage rating for it to work.
  • LEDs are diodes – devices that only allow current to flow in one direction. If you plug an LED in the wrong way round it wont work.
  • The short leg is usually the negative – end and the long leg is the positive end. Some LEDs also have a flat edge one their base that indicates the negative end.
  • LEDs come in two varieties – Single colour LEDs that give off light of a certain colour. RGB LEDs which can be programmed to display any colour.

Tutorial Video

Wiring Up the components


Click to enlarge


microbit single led with breadboard
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JavaScript Code Kingdoms Blocks Code

flashing led microbit code javascript

Python Code

Coding use Python is even easier than using JavaScript Code Kingdoms!

Challenge 1 – Flashing LED

Follow the tutorial video to get your LED flashing on and off every second.

Challenge 2 – SOS LED

Get your LED to flash the Emergency Morse code SOS

3 times:

  • Long Flash
  • 1 second pause

3 times:

  • Short Flash
  • 1 second pause

3 times:

  • Long Flash
  • 1 second pause

10 second pause



Challenge 3 – Alternating LEDs

Wire up 2 leds and get them to flash alternately every second.

Challenge 4 – Red Yellow Green

Wire up three lights and get them to light:

Red, then yellow, then blue

Challenge 5 – Traffic light LEDs

Wire up 3 LEDs (red,yellow,green) s so that they behave like a set of traffic lights.

  • Green
  • Yellow
  • Red
  • Wait 3 seconds
  • Red and Yellow
  • Green
  • Repeat forever


Challenge 6 – Button operated traffic light

Adapt your challenge 4 code so that the traffic lights are controlled by pressing the button!