pxt-calliope/docs/lessons/flashing-heart/activity.md

flashing heart blocks activity

Control images with a variable.

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@video td/videos/flashing-heart-0

In this activity, you will learn how to blink an image on the LED screen.

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To create a new script, go to the Create Code page and tap New Project under Block Editor.

Let's start by adding code that plots a heart image on the screen using show LEDs. Once you are done coding, don't forget to run your code in the simulator or the micro:bit.

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

We want to leave the image on the screen for 0.5 seconds (500 milliseconds), then clear the screen. We can use pause to wait and clear screen to turn off the LEDs.

basic.forever(() => {
    basic.showLeds(`
        . # . # .
        # # # # #
        # # # # #
        . # # # .
        . . # . .
        `)
    basic.pause(500)
    basic.clearScreen()
})

Finally, we can surround this code with a forever loop to repeat it and add a pause after clear screen to keep the screen off for a little while. Modify your code so that your code looks like this.

basic.forever(() => {
    basic.showLeds(`
        . # . # .
        # # # # #
        # # # # #
        . # # # .
        . . # . .
        `)
    basic.pause(500)
    basic.clearScreen()
    basic.pause(500)

})

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

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