External Buttons on a micro:bit

On the bottom edge of the micro:bit there are 5 gold strips called pins. These pins allow you to create circuits, or connect external things like LEDs or buttons.

• The Input/Output Pins on the micro:bit are “0”, “1”, and “2.” These allow you to connect LEDs or buttons.
• The "3V" pin is the 3 volt power pin that you can use to power external LEDs and other electronics.
• The GND pin is the ground pin. It’s used to complete electrical circuits when you connect headphones, LEDs, or external switches to the micro:bit.

To create a button or a switch, you just need a circuit that can be easily connected and disconnected. A button circuit can be created by connecting one wire to a data pin and another wire to a ground pin.

To "close" the circuit (which is like pressing a button) you connect the two wires, either by touching them to each other or connecting them to a piece of hardware (like a button or switch) that can be used to open and close the circuit.

An "open" button is equivalent to the button "up" event, while a "closed" circuit is like the button "down" event.

Creating Button Circuits

To create a button circuit you'll need a data pin, two wires, and a ground pin.

1. Connect a wire to your numbered data pin.
2. Connect a different wire to a ground pin.
3. Use one of the following blocks of in your code:
   • pinMode() tells your micro:bit that you want to use one of the external pads for either input or output. "Pin" is the generic term for the pads on the micro:bit, and pins can look different on other devices.
   • digitalWrite() tells your micro:bit to start or stop sending electricity to the device on that pin. 1 means "on", and 0 means "off"
   • createButton() block lets you assign an external button to a variable
   • onBoardEvent() block uses the same variable name to respond to input