Environment Detective: Exploring Our World with micro:bit

Overview

Ever wondered how technology can help us understand the world around us?

In this project, you are going to become an environment detective using your 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 → and its built-in sensors.

Just like your senses help you explore the world, the micro:bit can tell you:

• How warm or cold it is using its temperature sensorTemperature sensorA temperature sensor is a little part that measures how warm or cold it is around it, then turns that into a number your code can read. As the room heats up or cools down, the number changes too.Full entry →
• How bright or dark it is using its light sensorLight SensorA light sensor is a little part that measures how bright or dark it is around it, then turns that into a number your code can read. As the light changes, so does the number.Full entry →
• Which direction you are facing using its compassCompassA compass senses which way you are facing and turns it into a number your code can read, from 0 all the way round to 359. North is 0, east is 90, south is 180 and west is 270.Full entry →

You will make the readings appear on the micro:bit’s 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 →.

Are you ready? Let’s begin our detective adventure!

What you'll need

Key words

Set up EduBlocks

First, let’s create a new EduBlocks project.

1. Open your favourite web browser. Google Chrome or Microsoft Edge works well.
2. Go to app.edublocks.org.
3. Find Create New Project.
4. Select micro:bit.
5. Name your project Environment Detective.
6. Make sure Blocks is selected as the project type.
7. Select Create.

The EduBlocks micro:bit editor will now open.

Prepare the code area

We need to import the micro:bit tools, prepare the compass and add a loop that keeps checking the sensors.

1. Open Basic.
2. Select Imports.
3. Drag a from microbit import * block onto the # Start code here block.
4. Open Compass.
5. Drag a compass.calibrate() block underneath the import block.
6. Open Basic.
7. Select Loops.
8. Drag a while True: block underneath compass.calibrate().

Your starting code should look like this:

Sense the temperature

First, we will make the micro:bit display the temperature when you shake it.

1. Open Basic.
2. Select Logic.
3. Drag an if True: block inside the while True: block.
4. Open Accelerometer.
5. Drag accelerometer.was_gesture("shake") onto the True section of the if block.
6. Open Display.
7. Drag display.scroll(0) inside the shake block.
8. Change the 0 to temperature().
9. Open Basic.
10. Select Statements.
11. Add sleep(1000) underneath display.scroll(temperature()).
12. Change 1000 to 2000.
13. Open Display.
14. Add display.clear() underneath sleep(2000).

Your code should look like this:

Here’s what this bit of code is doing:

• The micro:bit waits until it detects a shake.
• It reads the temperature.
• It scrolls the temperature across the LED matrix.
• It waits for two seconds.
• It clears the display.

Sense the light level

Next, we will use button A to check whether the room is dark.

1. Open Basic.
2. Select Logic.
3. Add another if True: block underneath the whole temperature section.
4. Open Buttons.
5. Drag button_a.was_pressed() onto the True section.
6. Add another if True: block inside the button A block.
7. Open Basic, then Logic.
8. Drag a 0 == 0 comparison onto True.
9. Change == to <.
10. Add display.read_light_level() before the < symbol.
11. Change the second 0 to 100.

Your comparison should now say:

display.read_light_level() < 100

Show a picture when it is dark

1. Open Display.
2. Add display.show(10) inside the light-level check.
3. Add an Image.HEART block to replace 10.
4. Change HEART to HAPPY.
5. Open Basic, then Logic.
6. Add an else: block underneath the light-level check.
7. Open Display.
8. Add display.clear() inside else:.
9. Open Basic, then Statements.
10. Add sleep(1000) underneath the light section.
11. Change 1000 to 500.

Your light-sensing code should look like this:

When you press button A:

• The micro:bit checks the light level.
• If the light level is below 100, it shows a happy face.
• If the light level is 100 or higher, it clears the display.

The code uses an 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 → and a comparison operatorComparison OperatorsA comparison operator checks how two things measure up, for example whether they are equal or one is bigger than the other. It gives back a simple true or false answer.Full entry → to make this decision.

Build the compass code

Now we will use button B to display the compass direction as a number.

1. Open Basic.
2. Select Logic.
3. Add another if True: block underneath the whole button A section.
4. Open Buttons.
5. Drag button_b.was_pressed() onto True.
6. Open Display.
7. Add display.scroll(0) inside the button B block.
8. Open Compass.
9. Drag compass.heading() onto the 0.
10. Open Basic, then Statements.
11. Add sleep(1000) underneath the display block.
12. Change 1000 to 500.

Your code should look like this:

When you press button B, the micro:bit will display a number between 0 and 359.

Show compass letters

Numbers are useful, but letters are easier to recognise quickly.

We will now create a second button B section that shows N, E, S or W.

Create the direction variable

1. Add another if True: block underneath the compass-number section.
2. Open Buttons.
3. Add button_b.was_pressed() to the True section.
4. Open Variables.
5. Select Create a Variable.
6. Name the variable direction.
7. Add direction = 0 inside the button B block.
8. Open Compass.
9. Replace 0 with compass.heading().

The block should now say:

direction = compass.heading()

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 → stores information that can change. In this project, the direction variable stores the current compass heading.

Add the north check

1. Open Basic, then Logic.
2. Add an if True: block underneath direction = compass.heading().
3. Add a True and True block onto True.
4. Change and to or.
5. Add a comparison block to the first True.
6. Build the comparison direction > 315.
7. Add another comparison to the second True.
8. Build the comparison direction < 45.
9. Open Display.
10. Add display.show("Hello") inside the if block.
11. Change Hello to N.

The first check should now say:

if direction > 315 or direction < 45:

Add east

1. Open Basic, then Logic.
2. Add an elif True: block underneath the north section.
3. Build the comparison direction < 135.
4. Add display.show("Hello") inside it.
5. Change Hello to E.

Add south

1. Add another elif True: block.
2. Build the comparison direction < 225.
3. Add display.show("Hello") inside it.
4. Change Hello to S.

Add west

1. Add an else: block underneath the south section.
2. Add display.show("Hello") inside it.
3. Change Hello to W.
4. Add sleep(500) underneath the completed compass section.

Your finished compass code should look like this:

Download your code

Your environment detector is ready to transfer to the micro:bit.

1. Connect the micro:bit to your computer using the micro USB cable.
2. In EduBlocks, select Connect.
3. Follow the instructions on the screen to pair your micro:bit.
4. If your browser asks for permission, choose the micro:bit from the list.
5. Select Connect.
6. Select Flash to send the code to the micro:bit.

Test your environment detector

When the micro:bit first starts, it may ask you to tilt it in different directions until all the LEDs have lit up.

This is called calibrating. It helps the compass work out which direction is north.

Test the temperature

1. Shake the micro:bit.
2. Watch the temperature scroll across the LED matrix.
3. Move to a different room or go outside and try again.

Test the light level

1. Cover the micro:bit with your hand.
2. Press button A.
3. A happy face should appear if the light level is below 100.
4. Move the micro:bit somewhere brighter and press button A again.

Test the compass

1. Face one direction.
2. Press button B.
3. Look at the letter on the LED matrix.
4. Turn around and press button B again.

You should see N, E, S or W, depending on which direction the micro:bit is facing.

Try it yourself

Stuck? Quick fixes