pxt-calliope/docs/projects/rock-paper-scissors.md

rock paper scissors

~avatar avatar

@video td/videos/rock-paper-scissors-0

In this project, you will build a rock-paper-scissor game with the BBC micro:bit

~

Materials needed

• your BBC micro:bit, that's it!

1

We want the micro:bit to choose rock, paper, or scissors when it is shaken. Let's begin by creating an on shake condition so the micro:bit will run code when it is shaken.

input.onGesture(Gesture.Shake, () => {
    
})

Next, create a variable and store pick random number from 0 to 2. On shake, a number will be randomly picked from 0-2. We will randomly display an image based on the random number returned.

input.onGesture(Gesture.Shake, () => {
    let img = Math.random(3)
})

The micro:bit will look like it's showing 1 frame of the image by displaying the whole image when pick random is equal to 0. We can help the micro:bit randomly decide which image to use by pick random. The micro:bit will randomly pick the image to display with show LEDs and the pick random block.

input.onGesture(Gesture.Shake, () => {
    let img = Math.random(3)
    if (img == 2) {
        basic.showLeds(`
            # # # # #
            # . . . #
            # . . . #
            # . . . #
            # # # # #
            `)

    }
})

2

The micro:bit will look like it's showing 1 frame of the image by displaying the whole image when pick random is equal to 1. We can help the micro:bit randomly decide which image to use by pick random. The micro:bit will randomly pick the image to display with show LEDs and the pick random function.

~avatar avatar

Click on the blue gearwheel to open the if editor. Drag and drop the else if block in the if block to add it.

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input.onGesture(Gesture.Shake, () => {
    let img = Math.random(3)
    if (img == 0) {
        basic.showLeds(`
            # # # # #
            # . . . #
            # . . . #
            # . . . #
            # # # # #
            `)

    } else if (img == 1) {
        basic.showLeds(`
            . . . . .
            . # # # .
            . # # # .
            . # # # .
            . . . . .
            `)
    }
})

3

The micro:bit will look like it's showing 1 frame of the image by displaying the whole image when pick random is not equal to 0 and not equal to 1. We can help the micro:bit randomly decide which image to use by pick random. The micro:bit will randomly pick the image to display with show LEDs and the pick random function.

input.onGesture(Gesture.Shake, () => {
    let img = Math.random(3)
    if (img == 0) {
        basic.showLeds(`
            # # # # #
            # . . . #
            # . . . #
            # . . . #
            # # # # #
            `)

    } else if (img == 1) {
        basic.showLeds(`
            . . . . .
            . # # # .
            . # # # .
            . # # # .
            . . . . .
            `)
    } else {
        basic.showLeds(`
            . . . # #
            # # . # .
            . . # . .
            # # . # .
            . . . # #
            `)
    }
})

Your game is ready!

4

When the button A is pressed, increment the score by 1. You can select Game drawer then add change score by 1.

input.onButtonPressed(Button.A, () => {
    game.addScore(1)
})

5

After incrementing the score, display the total number of wins you have.

input.onButtonPressed(Button.A, () => {
    game.addScore(1)
    basic.showString("WINS:")
    basic.showNumber(game.score())
})

6

You have successfully tracked and displayed the number of wins on the micro:bit! However, what about losses? Use the Game drawer to change score by -1 when button B is pressed. Here are all the blocks you will need:

input.onButtonPressed(Button.B, () => {
    game.addScore(-1)
    basic.showString("LOSSES:")
    basic.showNumber(game.score())
})