pxt-calliope/docs/getting-started.md

Getting started

~avatar

Are you ready to build cool BBC micro:bit programs?

Here are some challenges for you. Unscramble the blocks in the editor to make real programs that work!

~

Happy face

There are three blocks in the editor (the area to the left). They should look like this:

basic.forever(() => {
    basic.showLeds(`
        . . . . .
        . # . # .
        . . . . .
        # . . . #
        . # # # .
        `)
    basic.showLeds(`
        . . . . .
        . . . . .
        . . . . .
        . . . . .
        . . . . .
        `)
});

When you run this program, you will see a smiley face, then a blank screen, then a smiley again -- it never stops! (That's because of the forever block.)

Click Compile to move your program to the BBC micro:bit!

Happy unhappy face

Draw an unhappy face instead of the blank screen. Click on the dots in the second show leds block until it matches the blocks below. Now you have an animation (cartoon) that shows a happy face, then an unhappy one, then a happy one again, forever (or until you turn off your micro:bit)!

basic.forever(() => {
    basic.showLeds(`
        . . . . .
        . # . # .
        . . . . .
        # . . . #
        . # # # .
        `)
    basic.showLeds(`
        . . . . .
        . # . # .
        . . . . .
        . # # # .
        # . . . #
        `)
});

Click Compile to move your program to the BBC micro:bit!

Your turn!

Pile up more show leds blocks to create your animation! Create an animation with at least 5 pictures. What does this animation show?

basic.forever(() => {
    basic.showLeds(`
        . . . . .
        . # . # .
        . . . . .
        # . . . #
        . # # # .
        `)
    basic.showLeds(`
        . . . . .
        . # . # .
        . . . . .
        # # # # #
        . . . . .
        `)
    basic.showLeds(`
        . . . . .
        . # . # .
        . . . . .
        . # # # .
        # . . . #
        `)
    basic.showLeds(`
        . . . . .
        . # . # .
        . . . . .
        # # # # #
        . . . # #
        `)
    basic.showLeds(`
        . . . . .
        # . # . .
        . . . . .
        # . . . #
        . # # # .
        `)
    basic.showLeds(`
        . . . . .
        . . # . #
        . . . . .
        # . . . #
        . # # # .
        `)
});

Click Compile to move your program to the BBC micro:bit!

~hint

You can find the show leds block in the Basic part of the editor.

~

Button A and button B

This program will show the word ANTEATER on the LED screen when you press button A.

input.onButtonPressed(Button.A, () => {
    basic.showString("ANTEATER");
});

~hint

The showString block can show letters, numbers, and punctuation on the micro:bit screen.

~

Now try to unscramble these blocks in the editor so that the micro:bit shows BANANA when you press button B.

input.onButtonPressed(Button.B, () => {
    basic.showString("BANANA");
});

~hint

You can find the letter B by clicking the letter A on the onButtonPressed block.

~

Click Compile to move your program to the BBC micro:bit!

Your turn!

Can you combine these blocks so your program shows your real name instead of ANTEATER when you press A, but your secret agent name instead of BANANA when you press B?

Shake

You can find when someone is shaking the BBC micro:bit by checking its accelerometer (it finds whether the micro:bit is speeding up or slowing down).

Unscramble these blocks in the editor to show a frownie when someone shakes the micro:bit. (Ouch!)

input.onGesture(Gesture.Shake, () => {
    basic.showLeds(`
. . . . .
. # . # .
. . . . .
. # # # .
# . . . #`);
});

Click Compile to move your program to the BBC micro:bit!

Tilting with gestures

You can also find when someone is tilting the micro:bit left or right, face up or face down, and logo up or logo down (the logo is the yellow oval picture at the top of the board). Tilting a micro:bit like this is called a gesture.

Try to build a Rock Paper Scissors game where you tilt the micro:bit left to show paper, right to show scissors, and down to show rock.

Unscramble these blocks in the editor and try this program on a real micro:bit!

input.onGesture(Gesture.TiltLeft, () => {
    basic.showLeds(`
# # # # #
# . . . #
# . . . #
# . . . #
# # # # #`);
});
input.onGesture(Gesture.LogoDown, () => {
    basic.showLeds(`
. . . . .
. # # # .
. # # # .
. # # # .
. . . . .`);
});
input.onGesture(Gesture.TiltRight, () => {
    basic.showLeds(`
# # . . #
# # . # .
. . # . .
# # . # .
# # . . #`);
});

Click Compile to move your program to the BBC micro:bit!

Pins

You can also use the pins as buttons. (The pins are the holes in the metal stripe at the bottom of the micro:bit board.) For example, hold the GND button with one hand and touch the 0 pin (called P0) with your other hand to tell the micro:bit you're pressing it.

Unscramble the blocks in the editor to show a smiley when you press pin P0.

input.onPinPressed(TouchPin.P0, () => {
    basic.showLeds(`
. . . . .
. # . # .
. . . . .
# . . . #
. # # # .`);
});

Click Compile to move your program to the BBC micro:bit!

Your turn!

Use the screen, buttons, gestures, and pins to make your own fun game with the BBC micro:bit! What about some of these?

• A backpack burglar alarm
• Daily news broadcaster for your class
• Animated jewelry
• A complete animated cartoon
• A calculator
• A music box

These are all things you can make with the BBC micro:bit by itself. Just think what you can do if you connect the micro:bit's pins to extra parts like microphones and other sensors!

Let's play Rock Paper Scissors!

~avatar avatar

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

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

Build a Rock Paper Scissors game with the BBC micro:bit! You can play the game with a friend who has it on a micro:bit. You can also play it with friends who are just using their hands.

START PROJECT

~

Materials needed

• Your BBC micro:bit -- that's it!

Step 1: Getting started

We want the micro:bit to choose rock, paper, or scissors when you shake it. Try creating an on shake block so when you shake the micro:bit, it will run part of a program.

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

Next, when you shake the micro:bit, it should pick a random number from 0 to 2 and store it in the variable weapon. (This variable is named weapon because rock, paper, and scissors are the weapons you use to battle your friends!)

Add a set block with a variable. Then add a pick random block, and store the random number in the variable, like this:

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

~hint

No one can predict random numbers. That's what makes them great for Rock Paper Scissors!

~

Each possible number these blocks can make (0, 1, or 2) means a different picture. We will show the right picture for that number on the LED screen.

Step 2: Picking paper

Put an if block after the let block that checks whether weapon is 0. Make sure the if block has an else if part and an else part.

Next, add a show leds block that shows a picture of a piece of paper:

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

    } else {

    }
})

Step 3: A random rock

Now we are going to add a new picture for the micro:bit to show when another random number comes up.

Make the else if part check if the variable weapon is 1. Then add a show leds block with a picture of a rock.

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

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

    }
})

Step 4: Suddenly scissors

Add a show leds block with a picture of scissors to the else part:

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

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

~hint

You don't need to check if weapon is 2 because 2 is the only number left out of 0, 1, and 2. That's why you can use an else instead of an else if.

~

Your game is ready!

Click Compile to move your program to the BBC micro:bit!

Have fun!

Step 5: Are you the greatest?

Here is a way you can make your Rock Paper Scissors game better. When button A is pressed, the micro:bit will add 1 to your score.

Open the Game drawer, and then add the block change score by 1 to your program, like this:

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

Step 6: Prove you're the greatest!

After your micro:bit can add 1 to the score, show how many wins you have.

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

Step 7: Staying honest

Success! Your micro:bit can track wins! But what about losses? Use the Game drawer to subtract 1 from your score when you press button B.

Here are all the blocks you will need:

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

Click Compile to move your program to the BBC micro:bit!

Your turn!

How else can you make your game better? Ever hear of Rock Paper Scissors Spock Lizard?