Pushbutton with micro:bit

Learn how to add an external pushbutton to the micro:bit

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Written By: Cherie Tan
)">

Difficulty

Easy

Steps

13

Time Required

Introduction

While the micro:bit already has two on-board push buttons, button A and button B, you can add more buttons to control the micro:bit. 

In this guide, you will learn to connect an external push button to the micro:bit, and get it to turn turn an LED on and off. The push button module is comprised of a momentary push button switch and an in-built resistor. 

After completing this guide, you will know how to add more buttons to your micro:bit which will come in handy when you go on to make all sorts of  projects.

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    • Before we put together the circuit, let's take a closer look at the Pushbutton Module. There are three pins here:

      S : This is the signal pin which we will connect to a GPIO pin on the micro:bit

      3.3V : Though it is unlabelled on the module, this middle pin will need to be connected to 3.3V on the micro:bit

      GND: In electronics, we define a point in a circuit to be a kind of zero volts or 0V reference point, on which to base all other voltage measurements. This point is called  ground or GND.

    • Voltage is the difference in potential between two points. As it is difficult to talk about voltage without a reference point, we need another point to compare it to. 

    • Insert the micro:bit into the breakout board . Make sure that the micro:bit is inserted in the right orientation, with the buttons facing inward as shown. 

  10. pins.setPull(DigitalPin.P0, PinPullMode.PullNone)
pins.setEvents(DigitalPin.P0, PinEventType.Edge)

    • Now open up MakeCode editor

    • Click on 'New Project'

    • Copy and paste the following code into the Javascript interface. 

  11. input.onPinPressed(TouchPin.P0, function () {
    pins.digitalWritePin(DigitalPin.P1, 1)
})
pins.setPull(DigitalPin.P0, PinPullMode.PullNone)
pins.setEvents(DigitalPin.P0, PinEventType.Edge)

    • Copy and paste this code into the Javascript interface in the MakeCode editor. 

  12. input.onPinPressed(TouchPin.P0, function () {
    pins.digitalWritePin(DigitalPin.P1, 1)
})
input.onPinReleased(TouchPin.P0, function () {
    pins.digitalWritePin(DigitalPin.P1, 0)
})
pins.setPull(DigitalPin.P0, PinPullMode.PullNone)
pins.setEvents(DigitalPin.P0, PinEventType.Edge)

    • After testing out the previous code, replace it with this in the Javascript interface.

    • To transfer the code to the micro:bit, follow these steps. Connect the micro:bit to your computer using a microUSB cable

    • Click on the 'Download' button in MakeCode editor. It should be on the bottom left-hand corner.

    • Locate the downloaded .hex file in your 'Downloads' folder.

    • Drag and drop the .hex file to the MICROBIT drive. 

    • Test the code out! Press the push button and the LED should light up briefly. Let it go and it should stop lighting up.