pxt-calliope/docs/lessons/night-light/activity.md

night light activity

Change the brightness of the micro:bit.

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@video td/videos/night-light-0

Welcome! This tutorial will teach you how to change the brightness of the micro:bit. Let's get started!

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The brightness of the LED screen can be changed by using the set brightness function. This function takes a number between 0 (off) and 255 (full brightness).

Let's build a little app that dims the screen when pressing button A.

Add the code show LEDs and select all LEDs to turn on all the LEDs. Don't hesitate to run your code to see what happens.

basic.showLeds(`
    # # # # #
    # # # # #
    # # # # #
    # # # # #
    # # # # #
    `)

The screen starts with a 50% brightness value by default (128). Add a new line of code to set the full brightness (255) using set brightness.

led.setBrightness(255)
basic.showLeds(`
    # # # # #
    # # # # #
    # # # # #
    # # # # #
    # # # # #
    `)

Add a new event handler for on button pressed(A) and add the code to set the brightness to 64.

led.setBrightness(255)
basic.showLeds(`
    # # # # #
    # # # # #
    # # # # #
    # # # # #
    # # # # #
    `)
input.onButtonPressed(Button.A, () => {
    led.setBrightness(64)
})

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Excellent, you're ready to continue with the challenges!

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