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 to start exploring? Let’s begin our detective adventure!

What you'll need

Key words

Set up MakeCode

You can complete this project on a computer, tablet or phone.

Using a computer

1. Open your favourite web browser. Google Chrome or Microsoft Edge works well.
2. Go to makecode.microbit.org.
3. Select New Project.
4. Name your project Environment Detective.
5. Select Create.

Using a tablet or phone

1. Open the micro:bit app.
2. Select Create Code.
3. Select New Project.
4. Name your project Environment Detective.
5. Select Create.

Whichever device you use, your coding area will look similar to this:

Prepare the code area

MakeCode gives you two blocks to begin with, but we do not need them for this project.

Let’s clear the coding area and add the three events that will control our environment detector.

1. Drag the on start block over to the menu on the left and drop it into the bin.
2. Delete the forever block in the same way.
3. Open Input.
4. Drag an on shake block into the coding area.
5. Open Input again.
6. Drag an on button A pressed block into the coding area.
7. Right-click the on button A pressed block, or press and hold it on a touchscreen.
8. Select Duplicate.
9. On the copied block, change A to B.

You should now have three event blocks:

• on shake
• on button A pressed
• on button B pressed

Sense the temperature

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

1. Open Basic.
2. Drag a show number block into the on shake block.
3. Open Input.
4. Find the temperature block.
5. Drag it onto the 0 inside the show number block.

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 sensor.
• It shows the temperature as a number on the LED matrix.

Sense the light level

Next, we will use button A to measure the light around the micro:bit.

1. Open LED.
2. Drag a plot bar graph of block into the on button A pressed block.
3. Open Input.
4. Find the light level block.
5. Drag it onto the first 0 in the plot bar graph of block.
6. Change the number after up to from 0 to 255.

Your code should look like this:

When you press button A, the LED matrix will draw a bar graph showing the light level.

• In a dark place, fewer LEDs will light up.
• In a bright place, more LEDs will light up.

Build the compass code

Now we will use button B to read the compass.

Let’s begin with the easy version, which shows the compass direction as a number.

1. Open Basic.
2. Drag a show number block into the on button B pressed block.
3. Open Input.
4. Find the compass heading block.
5. Drag it onto the 0 in the show number block.

Your code should look like this:

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

The number tells you which direction the micro:bit is pointing:

Show compass letters

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

We will now replace the number with N, E, S or W.

Create the direction variable

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 → is like a labelled box that stores information.

1. Remove the show number compass heading block from on button B pressed.
2. Open Variables.
3. Select Make a Variable.
4. Name the variable direction.
5. Drag set direction to 0 into the on button B pressed block.
6. Open Input.
7. Drag compass heading onto the 0.

Your block should now say:

set direction to compass heading

Add the north check

1. Open Logic.
2. Drag an if true then else block underneath set direction to compass heading.
3. Open Logic again.
4. Drag an or block onto true.
5. Add a comparison block to each side of or.
6. Build these two comparisons:
   • direction > 315
   • direction < 45
7. Open Basic.
8. Put a show string block inside the first if section.
9. Change the text from Hello! to N.

This checks whether the direction is near the top of the compass circle.

Add east

1. Select the + underneath the else section to add an else if.
2. Add a comparison that says direction < 135.
3. Put a show string block inside it.
4. Change its text to E.

Add south

1. Select the + again to add another else if.
2. Add a comparison that says direction < 225.
3. Put a show string block inside it.
4. Change its text to S.

Add west

1. Put a show string block inside the final else section.
2. Change its text to W.

Your finished compass code should look like this:

The code uses if statementsIf 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 comparison operatorsComparison 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 decide which letter to show.

Download your code

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

Using a computer

1. Connect your micro:bit to the computer with the micro USB cable.
2. In MakeCode, select the three dots next to Download.
3. Select Connect Device.
4. Follow the instructions on the screen.
5. Choose your micro:bit from the list.
6. Select Connect.
7. Select Download to send the code to the micro:bit.

Using a tablet or phone

1. Select Download.
2. Follow the instructions on the screen to pair the micro:bit with the app.
3. Send the code to your micro:bit.

Test your environment detector

You can test the project using the MakeCode simulator or a real micro:bit.

Test the simulator

The simulator is the pretend micro:bit on the left of the MakeCode screen.

Temperature

1. Select the white circle next to Shake.
2. Watch the temperature appear on the LED matrix.
3. Move the temperature slider and try shaking it again.

Light

1. Find the light control above button A on the simulator.
2. Drag the yellow section to change the light level.
3. Press button A.
4. Watch the LED bar graph change.

Compass

1. Press button B.
2. Watch the compass direction appear.
3. Drag the micro:bit logo at the top of the simulator to turn it.
4. Press button B again and see whether the letter changes.

Test a real micro:bit

• Temperature: Shake the micro:bit to display the temperature.
• Light: Press button A. Try covering the micro:bit or shining a torch towards it.
• Compass: Turn in a different direction and press button B.

Try it yourself

Stuck? Quick fixes