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

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2016-03-26 00:47:20 +01:00
# night light activity
2016-11-02 01:44:37 +01:00
Change the brightness of the @boardname@.
2016-03-26 00:47:20 +01:00
### ~avatar avatar
2016-11-02 01:44:37 +01:00
Welcome! This tutorial will teach you how to change the brightness of the @boardname@. Let's get started!
2016-03-26 00:47:20 +01:00
### ~
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.
```blocks
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`.
```blocks
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`.
```blocks
led.setBrightness(255)
basic.showLeds(`
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
`)
input.onButtonPressed(Button.A, () => {
led.setBrightness(64)
})
```
### ~avatar boothing
2016-04-13 17:27:45 +02:00
Excellent, you're ready to continue with the [challenges](/lessons/night-light/challenges)!
2016-03-26 00:47:20 +01:00
### ~