504 lines
11 KiB
Markdown
504 lines
11 KiB
Markdown
# Getting started
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## ~avatar
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Are you ready to build cool BBC micro:bit programs?
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Here are some challenges for you. Arrange the blocks in the editor
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to make real programs that work!
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## ~
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### Happy face
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Use the **Basic** drawer in the editor (to the left)
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to drag out and arrange three blocks (two `show leds` and one `forever` block)
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to create this program:
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```blocks
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basic.forever(() => {
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basic.showLeds(`
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. . . . .
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. # . # .
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. . . . .
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# . . . #
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. # # # .
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`)
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basic.showLeds(`
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. . . . .
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. . . . .
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. . . . .
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. . . . .
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. . . . .
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`)
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});
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```
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When you run this program (click the **Play** button) you will see a smiley face, then a blank
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screen, then a smiley again -- it never stops! (That's because of the
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``forever`` block.)
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Click **Compile** to move your program to the BBC micro:bit!
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### Happy unhappy face
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Draw an unhappy face instead of the blank screen. Click on the dots
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in the second ``show leds`` block until it matches the blocks below.
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Now you have an **animation** (cartoon) that shows a happy face,
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then an unhappy one, then a happy one again, forever (or until
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you turn off your micro:bit)!
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```blocks
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basic.forever(() => {
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basic.showLeds(`
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. . . . .
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. # . # .
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. . . . .
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# . . . #
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. # # # .
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`)
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basic.showLeds(`
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. . . . .
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. # . # .
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. . . . .
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. # # # .
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# . . . #
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`)
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});
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```
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Click **Compile** to move your program to the BBC micro:bit!
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### Your turn!
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Pile up more ``show leds`` blocks to create an animation! Create an
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animation with at least 5 pictures. What does this animation show?
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```blocks
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basic.forever(() => {
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basic.showLeds(`
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. . . . .
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. # . # .
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. . . . .
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# . . . #
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. # # # .
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`)
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basic.showLeds(`
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. . . . .
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. # . # .
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. . . . .
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# # # # #
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. . . . .
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`)
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basic.showLeds(`
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. . . . .
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. # . # .
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. . . . .
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. # # # .
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# . . . #
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`)
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basic.showLeds(`
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. . . . .
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. # . # .
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. . . . .
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# # # # #
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. . . # #
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`)
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basic.showLeds(`
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. . . . .
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# . # . .
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. . . . .
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# . . . #
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. # # # .
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`)
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basic.showLeds(`
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. . . . .
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. . # . #
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. . . . .
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# . . . #
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. # # # .
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`)
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});
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```
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Click **Compile** to move your program to the BBC micro:bit!
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#### ~hint
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You can find the ``show leds`` block in the **Basic** part of the editor.
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#### ~
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### Button A and button B
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This program will show the word **ANTEATER** on the LED
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screen when you press button `A`.
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```blocks
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input.onButtonPressed(Button.A, () => {
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basic.showString("ANTEATER");
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});
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```
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#### ~hint
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The ``showString`` block can show letters, numbers, and punctuation
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on the micro:bit screen.
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#### ~
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Now try to unscramble these blocks in the editor so that the micro:bit
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shows **BANANA** when you press button `B`.
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```shuffle
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input.onButtonPressed(Button.B, () => {
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basic.showString("BANANA");
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});
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```
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#### ~hint
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You can find the letter `B` by clicking the letter `A` on the
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``onButtonPressed`` block.
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#### ~
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Click **Compile** to move your program to the BBC micro:bit!
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#### Your turn!
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Can you combine these blocks so your program shows your real name
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instead of **ANTEATER** when you press `A`, but _your secret agent
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name_ instead of **BANANA** when you press `B`?
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### Shake
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You can find when someone is shaking the BBC micro:bit by checking its
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**accelerometer** (it finds whether the micro:bit is speeding up or
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slowing down).
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Unscramble these blocks in the editor to show a frownie when someone
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shakes the micro:bit. (Ouch!)
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```shuffle
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input.onGesture(Gesture.Shake, () => {
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basic.showLeds(`
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. . . . .
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. # . # .
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. . . . .
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. # # # .
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# . . . #`);
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});
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```
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Click **Compile** to move your program to the BBC micro:bit!
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### Pins
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You can also use the pins as buttons. (The pins are the holes in the
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metal stripe at the bottom of the micro:bit board.) For example, hold
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the ``GND`` button with one hand and touch the ``0`` pin (called
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``P0``) with your other hand to tell the micro:bit you're pressing it.
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Unscramble the blocks in the editor to show a heart when you touch
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pin ``P0``.
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```shuffle
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input.onPinPressed(TouchPin.P0, () => {
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basic.showLeds(`
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. # . # .
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# . # . #
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# . . . #
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. # . # .
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. . # . .`);
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});
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```
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Click **Compile** to move your program to the BBC micro:bit!
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## ~hint
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Try this experiment: find a friend and hold hands. Touch the ``GND``
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pin while your friend presses the ``P0`` pin. You should see the
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heart! The electric current is going through your bodies and across
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your handshake to make it happen!
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## ~
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## The amazing coin flipper
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### ~avatar avatar
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Are you trying to choose whether to play soccer or go to the movies
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instead, or which toppings to have on your pizza? Build a coin
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flipping machine with the BBC micro:bit to choose for you!
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### ~
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Here are the blocks to make your coin flipper. When you press button
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`B`, the coin flipper will show either `H` for heads or `T` for tails
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on the LED screen.
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```blocks
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input.onButtonPressed(Button.B, () => {
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if (Math.randomBoolean()) {
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basic.showString("H");
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} else {
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basic.showString("T");
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}
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});
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```
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### ~hint
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The ``pick random true or false`` block randomly tells the ``if``
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block `true` or `false`. If the ``pick`` block picked `true`, the
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``if`` block shows the letter `H`. Otherwise, it shows the letter `T`.
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That's it!
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### ~
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### Keeping score
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#### ~avatar
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To keep track out of how many guesses you've won,
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add these blocks to your coin flipper:
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#### ~
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```blocks
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input.onButtonPressed(Button.A, () => {
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game.addScore(1);
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});
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input.onButtonPressed(Button.AB, () => {
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basic.showNumber(game.score());
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});
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```
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These blocks mean that if you press button `A`, you will add `1` to
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your score, and if you press `A` and `B` together, the micro:bit will
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show your score.
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When you're done, your coin flipping program should look like this:
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```blocks
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input.onButtonPressed(Button.B, () => {
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if (Math.randomBoolean()) {
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basic.showString("H");
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} else {
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basic.showString("T");
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}
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});
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input.onButtonPressed(Button.A, () => {
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game.addScore(1);
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});
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input.onButtonPressed(Button.AB, () => {
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basic.showNumber(game.score());
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});
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```
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Flip until your thumbs get tired!
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## Let's play Rock Paper Scissors!
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### ~avatar avatar
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Build a Rock Paper Scissors game with the BBC micro:bit! You can play
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the game with a friend who has it on a micro:bit. You can also play
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it with friends who are just using their hands. (The game is built
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like a coin flipper, but with three choices instead of two.)
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### ~
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## Step 1: Getting started
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We want the micro:bit to choose rock, paper, or scissors when you
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shake it. Try creating an ``on shake`` block so when you shake the
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micro:bit, it will run part of a program.
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Clear up the blocks and add the blocks below.
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```blocks
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input.onGesture(Gesture.Shake, () => {
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})
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```
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Next, when you shake the micro:bit, it should pick a random number from `0` to `2`
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and store it in the variable `item`.
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Add a ``set`` block with a variable. Then add a ``pick random`` block,
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and store the random number in the variable,
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like this:
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```blocks
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input.onGesture(Gesture.Shake, () => {
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let item = Math.random(3)
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})
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```
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### ~hint
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No one can predict random numbers. That's what makes them great for Rock Paper Scissors!
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### ~
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Each possible number these blocks can make (`0`, `1`, or `2`) means a different picture.
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We will show the right picture for that number on the LED screen.
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## Step 2: Picking paper
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Put an ``if`` block after the ``let`` block that checks whether
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`item` is `0`. Make sure the ``if`` block has an ``else if`` part
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and an ``else`` part.
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Next, add a ``show leds`` block that shows a
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picture of a piece of paper:
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```blocks
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input.onGesture(Gesture.Shake, () => {
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let item = Math.random(3)
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if (item == 0) {
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basic.showLeds(`
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# # # # #
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# . . . #
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# . . . #
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# . . . #
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# # # # #
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`)
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} else if (false) {
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} else {
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}
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})
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```
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## Step 3: A random rock
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Now we are going to add a new picture for the micro:bit to show
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when another random number comes up.
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Make the ``else if`` part check if the variable `item` is `1`.
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Then add a ``show leds`` block with a picture of a rock.
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```blocks
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input.onGesture(Gesture.Shake, () => {
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let item = Math.random(3)
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if (item == 0) {
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basic.showLeds(`
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# # # # #
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# . . . #
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# . . . #
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# . . . #
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# # # # #
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`)
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} else if (item == 1) {
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basic.showLeds(`
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. . . . .
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. # # # .
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. # # # .
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. # # # .
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. . . . .
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`)
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} else {
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}
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})
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```
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## Step 4: Suddenly scissors
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Add a ``show leds`` block with a picture of scissors to the ``else`` part:
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```blocks
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input.onGesture(Gesture.Shake, () => {
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let item = Math.random(3)
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if (item == 0) {
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basic.showLeds(`
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# # # # #
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# . . . #
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# . . . #
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# . . . #
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# # # # #
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`)
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} else if (item == 1) {
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basic.showLeds(`
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. . . . .
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. # # # .
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. # # # .
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. # # # .
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. . . . .
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`)
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} else {
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basic.showLeds(`
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# # . . #
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# # . # .
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. . # . .
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# # . # .
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# # . . #
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`)
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}
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})
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```
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### ~hint
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You don't need to check if `item` is `2` because `2` is the only number left out of `0`, `1`, and `2`.
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That's why you can use an ``else`` instead of an ``else if``.
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### ~
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Your game is ready!
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Click **Compile** to move your program to the BBC micro:bit!
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Have fun!
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## Step 5: Are you the greatest?
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Here is a way you can make your Rock Paper Scissors game better.
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When button ``A`` is pressed,
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the micro:bit will add `1` to your score.
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Open the ``Game`` drawer, and then add the block ``change score by 1`` to your program,
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like this:
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```blocks
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input.onButtonPressed(Button.A, () => {
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game.addScore(1)
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})
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```
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## Step 6: Prove you're the greatest!
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After your micro:bit can add `1` to the score, show how many wins you have.
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```blocks
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input.onButtonPressed(Button.A, () => {
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game.addScore(1)
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basic.showString("WINS:")
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basic.showNumber(game.score())
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})
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```
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## Step 7: Staying honest
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Success! Your micro:bit can track wins!
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But what about losses?
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Use the ``Game`` drawer to subtract `1` from your score when you press button `B`.
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Here are all the blocks you will need:
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```shuffle
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input.onButtonPressed(Button.B, () => {
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game.addScore(-1)
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basic.showString("LOSSES:")
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basic.showNumber(game.score())
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})
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```
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Click **Compile** to move your program to the BBC micro:bit!
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# Want to do more?
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There are [10 great projects](/projects) waiting for you.
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