pxt-calliope/docs/reference/js/lessons/night-light/activity.md
2016-04-13 08:27:45 -07:00

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night light activity

change the brightness of the BBC 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 BBC micro:bit. Let's get started!

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The brightness of the LED screen can be changed by using the led->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 led->plot all to turn on all the LEDs. Don't hesitate to run your code to see what happens.

led.plotAll() // ***

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

led.setBrightness(255) // ***
led.plotAll()

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

led.setBrightness(255)
led.plotAll()
input.onButtonPressed(Button.A, () => {
    led.setBrightness(64) // ***
}) // ***

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

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