MicroFit - Your very own Step Counter

Overview

Ever wondered how a smartwatch or fitness band counts your steps? In this project, you're going to build your very own step counter using a micro:bitmicro:bitThe micro:bit is a tiny programmable computer, about the size of a matchbox, made for learning to code. It has two buttons, a grid of little red LED lights and built-in sensors that can detect movement, light and temperature.Full entry →!

Inside your micro:bit is a clever little sensor called an accelerometerAccelerometerAn accelerometer is a tiny part inside the micro:bit that senses movement, like tilting, shaking or being turned over. It turns that movement into numbers your code can react to.Full entry →. It can feel when the micro:bit moves. We'll use it to spot every step you take, add them up, and show the total on the LED matrixLED MatrixThe LED matrix is the grid of little red lights on the front of the micro:bit. By switching them on and off in patterns, your code can show numbers, letters and tiny pictures.Full entry → (the grid of lights on the front).

The best bit? When you're done, you'll have a real working fitness tracker you can pop on and take outside. Don't worry if something doesn't work first time, that's all part of coding. Let's give it a go!

What you'll need

Key words

Set up your micro:bit Python Editor

1. Open your web browser. We recommend Google Chrome or Microsoft Edge.
2. In the address bar type python.microbit.org.
3. Give your project a name: select the project name box at the top of the editor and type MicroFit.
4. Close the left-hand panel by selecting the arrow pointing to the left.

5. Delete the code on lines 5 to 9 in the main code area.

Create a variable

On line 3, type steps = 0 to create a variableVariableA variable is something that can change. Think of it like a labelled box: you pop something inside, and the label tells you what it is. You can swap what's inside whenever you like.Full entry → called steps, set to 0 for when the code starts. Press Enter to make a new line.

Create a while True loop

Type while True: and press Enter. This creates a while loopWhile loopA while loop keeps repeating its instructions for as long as something stays true. The moment that thing stops being true, the loop stops.Full entry →, so anything inside it runs while the condition stays true. Notice your cursor automatically indents, that's how Python shows what's inside the loop.

Detect a shake

1. Type if accelerometer.was_gesture('shake'): and press Enter. The cursor indents again.
2. Type steps += 1.

This if statementIf statementAn if statement checks whether something is true, and only runs its instructions when it is. It's how code makes decisions.Full entry → adds 1 to your steps variable every time the micro:bit detects a shake.

Pause the code

Type sleep(500). This pauses the code for half a second, giving the micro:bit time to do other things, like check for the button press we'll add next. Press Enter, then delete the indent so the cursor lines back up with the if accelerometer.was_gesture('shake'): line.

Reset the steps with button A

1. Type if button_a.was_pressed(): and press Enter. This detects a buttonButtonA button is a switch you press to tell your project to do something. The code can check whether it's being pressed or not.Full entry → press, and the cursor indents.
2. Type steps = 0 to reset the steps variable back to 0 when button A is pressed.
3. Press Enter, then delete the indent so the cursor lines back up with the if button_a.was_pressed(): line.

Show the number of steps

Type display.scroll(steps). This scrolls the number of steps across the LED matrixLED MatrixThe LED matrix is the grid of little red lights on the front of the micro:bit. By switching them on and off in patterns, your code can show numbers, letters and tiny pictures.Full entry → on the front of the micro:bit.

Downloading Your Code

1. Connect the micro:bit to the computer with the micro USB cable.
2. Select the three dots next to Send to micro:bit.
3. Select Connect and follow the on-screen prompts.
4. Select Send to micro:bit to download the code.

Run it and Watch

In the web browser

The Python editor has a built-in micro:bit simulator, handy if you haven't got a micro:bit to hand. Below the simulator you'll see the shake function is already selected. Select the play button next to it to simulate a shake and show your step count on the LED matrix.

On a real micro:bit

Once your code's downloaded, give the micro:bit a shake and watch the step counter climb. Why not go further? Attach a battery pack, strap the micro:bit to you or pop it in your pocket, and head outside to see how many steps you can rack up.

Try it yourself

Stuck? Quick fixes