pxt-calliope/olddocs/lessons/pogo/activity.md
Tom Ball f4eca66648 move lessons out of web site
will move select lessons back to "educators" section
2016-06-14 11:49:58 -04:00

165 lines
4.7 KiB
Markdown

# pogo activity
Construct a counter that uses acceleration.
Welcome! This activity will teach how to construct a pendulum that glows using acceleration. Let's get started!
Create a **forever** loop that will constantly display the appropriate brightness on the LED display. Now let's measure the acceleration on the `y` axis and store that value in a variable. The `acceleration(y)` function will provide the value.
```blocks
basic.forever(() => {
let acc = input.acceleration(Dimension.Y)
})
```
Since the micro:bit will be swinging up and down, we need to store the variable called jumps. We will set the variable called jumps to 0 to store the number 0.
```blocks
let jumps = 0
basic.forever(() => {
let acc = input.acceleration(Dimension.Y)
})
```
The function `acceleration(y)` gets the acceleration value (milli g-force), in the `y` dimension. If the `acceleration(y)`is greater than 2000 milli g-force, we will change jumps by 1. If jumping is greater than 2000 milli-gravities, then change jumps by 1 and display a smiley on the BBC micro:bit. Finally, we will remove the smiley image from the screen
```blocks
let jumps = 0
basic.forever(() => {
let acc = input.acceleration(Dimension.Y)
if (acc > 2000) {
jumps = jumps + 1;
basic.showLeds(`
. . . . .
. # . # .
. . # . .
# . . . #
. # # # .
`)
basic.clearScreen()
}
})
```
Now let's register an event handler that will execute whenever an input button (A) is pressed during program execution. If you press button A, then show the number of jumps greater than 2000 milli-gravities on the BBC micro:bit.
```blocks
let jumps = 0
basic.forever(() => {
let acc = input.acceleration(Dimension.Y)
if (acc > 2000) {
jumps = jumps + 1;
basic.showLeds(`
. . . . .
. # . # .
. . # . .
# . . . #
. # # # .
`)
basic.clearScreen()
}
})
input.onButtonPressed(Button.A, () => {
basic.showNumber(jumps)
})
```
If you press button A+B together, then reset the jump counter to 0 on the BBC micro:bit. Finally, we will show the show the jump counter on the micro:bit
```blocks
let jumps = 0
basic.forever(() => {
let acc = input.acceleration(Dimension.Y)
if (acc > 2000) {
jumps = jumps + 1;
basic.showLeds(`
. . . . .
. # . # .
. . # . .
# . . . #
. # # # .
`)
basic.clearScreen()
}
})
input.onButtonPressed(Button.A, () => {
basic.showNumber(jumps)
})
input.onButtonPressed(Button.AB, () => {
let jumps = 0
basic.showNumber(jumps)
})
```
We want to setup the radio communication between an additional micro:bit. We first must send number for jumps. The additional micro:bit will receive the number and show number on data received. We are now displaying the current jump count on the second micro:bit
```blocks
let jumps = 0
basic.forever(() => {
let acc = input.acceleration(Dimension.Y)
if (acc > 2000) {
jumps = jumps + 1;
radio.sendNumber(jumps)
basic.showLeds(`
. . . . .
. # . # .
. . # . .
# . . . #
. # # # .
`)
basic.clearScreen()
}
})
input.onButtonPressed(Button.A, () => {
basic.showNumber(jumps)
})
input.onButtonPressed(Button.AB, () => {
let jumps = 0
basic.showNumber(jumps)
})
radio.onDataReceived(() => {
basic.showNumber(radio.receiveNumber())
})
```
We want to stop animation so every time the number of jumps increase by 1 the second micro:bit will not also display smiley from show leds. So we add the code stop animation
```blocks
let jumps = 0
basic.forever(() => {
let acc = input.acceleration(Dimension.Y)
if (acc > 2000) {
jumps = jumps + 1;
radio.sendNumber(jumps)
basic.showLeds(`
. . . . .
. # . # .
. . # . .
# . . . #
. # # # .
`)
basic.clearScreen()
}
})
input.onButtonPressed(Button.A, () => {
basic.showNumber(jumps)
})
input.onButtonPressed(Button.AB, () => {
let jumps = 0
basic.showNumber(jumps)
})
radio.onDataReceived(() => {
basic.showNumber(radio.receiveNumber())
led.stopAnimation()
})
```
Connect the first micro:bit to your computer using your USB cable and run the pogo script on it.
Connect the second micro:bit to your computer using your USB cable and run the pogo script on it.
The first person and second person take turns jumping in the “y” direction while the other player uses the micro:bit to track the results on the micro:bit!