Clap Lights

1. Introduction

The new micro:bits have a microphone to help them detect sound 🎤

Let’s learn how to use a clap 👏 to switch your micro:bit’s lights on and off!

Clap lights banner message

2. Setting up the sound input

🔊 Reacting to sound 🔊


► From the ||input:Input|| category, find the ||input:on [loud] sound|| container and add it to your workspace.

input.onSound(DetectedSound.Loud, function () {

})

3. Creating a lightsOn variable

🤿 Diving right in 🤿

Let’s begin by creating a variable to keep track of whether the micro:bit’s lights are on or off.


► In the ||variables:Variables|| category, click on Make a Variable... and make a variable named lightsOn.

4. Displaying LEDs part 1

🔆 On or not? 🌑

In this step, we’ll be using an if then / else statement.


► From the ||logic:Logic|| category, grab an ||logic:if <true> then / else|| block and snap it into your ||input:on [loud] sound|| container.

► Look in the ||variables:Variables|| category. Find the new ||variables:lightsOn|| variable and snap it in to replace the ||logic:<true>|| value in your ||logic:if <true> then / else|| statement.

let lightsOn = 0
input.onSound(DetectedSound.Loud, function () {
    // @highlight
    if (lightsOn) {

    } else {

    }
})

5. Displaying LEDs part 2

🌞 Lighting the display 🌞


► From ||basic:Basic||, grab ||basic:show leds|| and snap it into the top container of your ||logic:if then / else|| statement.

► Set the lights to a pattern you like!
💡 In the hint, we chose to turn on all of the outside lights. Feel free to make your own design 🎨

let lightsOn = 0
input.onSound(DetectedSound.Loud, function () {
    if (lightsOn) {
        // @highlight
        basic.showLeds(`
            # # # # #
            # . . . #
            # . . . #
            # . . . #
            # # # # #
            `)
    } else {
    }
})

6. Clearing the screen

► From ||basic:Basic||, find ||basic:clear screen|| and snap it into the bottom container of your ||logic:if then / else|| section.
💡 This will turn the display off if lightsOn is not true.

let lightsOn = 0
input.onSound(DetectedSound.Loud, function () {
    if (lightsOn) {
        basic.showLeds(`
            # # # # #
            # . . . #
            # . . . #
            # . . . #
            # # # # #
            `)
    } else {
        // @highlight
        basic.clearScreen()
    }
})

7. Setting the lightsOn variable

🎬 Lights, camera, action ✨

Just like we’d toggle a light switch, each time we clap, we want to flip the variable lightsOn to the opposite of what it was before.


► From ||variables:Variables||, locate ||variables:set [lightsOn] to [0]|| and snap it in at the very top of your ||input:on [loud] sound|| container.

► From the ||logic:Logic|| category, find the ||logic:not <>|| operator and use it to replace the [0] in ||variables:set [lightsOn] to [0]||.

► From ||variables:Variables||, grab ||variables:lightsOn|| and snap it into the empty part of the ||logic:not <>|| operator.

let lightsOn = false
input.onSound(DetectedSound.Loud, function () {
    // @highlight
    lightsOn = !(lightsOn)
    if (lightsOn) {
        basic.showLeds(`
            # # # # #
            # . . . #
            # . . . #
            # . . . #
            # # # # #
            `)
    } else {
        basic.clearScreen()
    }
})

8. Testing in the simulator

💡 Test what you’ve created 💡


► Check out the simulator!

► Click on the pink slider bar beneath the microphone icon and drag it up and down.
💡 Right now, your micro:bit thinks that anything above 128 is loud. Every time the sound goes > 128, your lights should switch on/off.

8. Set loud sound threshold

Your micro:bit might detect sounds when you don’t want it to. Setting a sound threshold could help 🔉🔊


► Click on the ||input:Input|| category. A new category should show up beneath it called ||input:...more||.

► From ||input:...more||, grab ||input:set [loud] sound threshold to [128]|| and snap it into your empty ||basic: on start|| container.
💡 Try to change the value of your sound threshold so that every time you clap, your lights will turn on if they are off and vice versa.

// @highlight
input.setSoundThreshold(SoundThreshold.Loud, 150)

9. Testing, round 2

👏 YOU DID IT! 👏

Don’t forget to test your code in the simulator!

If you have a new micro:bit (the one with the shiny gold logo at the top), download this code and try it out!

let lightsOn = false
input.onSound(DetectedSound.Loud, function () {
    lightsOn = !(lightsOn)
    if (lightsOn) {
        basic.showLeds(`
            # # # # #
            # . . . #
            # . . . #
            # . . . #
            # # # # #
            `)
    } else {
        basic.clearScreen()
    }
})
input.setSoundThreshold(SoundThreshold.Loud, 150)