Lesson 5: Conditionals (If / Else)

In this lesson, you’ll learn how to use conditionals on the Micro:bit to make your program change its behavior based on different situations. By the end, you’ll use if / else statements to react to movement (speed) and button input.

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What You’ll Learn

• What an if / else statement is and how it works
• How to use comparisons like >, <, and =
• How to change behavior based on speed (movement)
• How to change behavior based on input (button presses)

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Steps

1. Open MakeCode

Need step-by-step help? Go here

If you are happy to figure it out on your own, go to: https://makecode.microbit.org/

Click New Project and name it: Conditionals

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2. Get the Speed (Acceleration)

The micro:bit has a motion sensor called an accelerometer. We can use it to measure how fast the device is moving.

• Go to Input
• Find acceleration (strength)
• This value will be our speed

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3. Add an IF / ELSE Block

Now we’ll make the Micro:bit react differently depending on the speed.

• Go to Input → drag on shake into the workspace
• Go to Logic → drag if / else inside it

Condition:

acceleration (strength) > 800

This means:

• If the speed is greater than 800 → do one thing
• Otherwise → do something else

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4. Show Different Icons

Inside the IF section:

• Go to Basic → add show icon
• Choose a Sad face 😞

Inside the ELSE section:

• Add show icon
• Choose a Happy face 🙂

Test it:

• Shake the Micro:bit hard → 😞
• Shake it gently → 🙂

✅ You just used a conditional!

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5. Use a Button + Conditional

Now let’s check the speed using Button A.

• Go to Input → drag on button A pressed
• Add if / else inside

Condition:

acceleration (strength) > 800

Inside IF:

• Show text: FAST

Inside ELSE:

• Show text: SLOW

Test it:

• Move the micro:bit fast, then press A → shows FAST
• Keep it still, then press A → shows SLOW

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Extra Challenges (Optional)

Try one or more:

• Add a sound when the speed is too high
• Change the threshold from 800 to 400 or 1200
• Add Button B to check a different value
• Use AND / OR conditions:

  if speed > 800 AND button B is pressed
  

• Send a radio message only when the condition is true

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Reflection

• Why is it useful for a program to make decisions?
• Where do you see IF / ELSE in real life?
• How could conditionals be used in a game or alarm system?