109 lines
2.4 KiB
Markdown
109 lines
2.4 KiB
Markdown
# glowing pendulum block activity
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Construct a pendulum that glows using acceleration.
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Welcome! This activity will teach how to construct a pendulum that glows using acceleration. Let's get started!
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Turn on all the LEDs.
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```blocks
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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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Create a **forever** loop that will constantly display the appropriate brightness on the LED display.
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```blocks
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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.forever(() => {
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})
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```
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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.
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```blocks
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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.forever(() => {
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let acceleration = input.acceleration(Dimension.Y);
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});
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```
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Since the micro:bit will be swinging back and forth, the acceleration will only be positive half of the time. Thus, to always get a positive value, we want to take the absolute value of the acceleration.
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```blocks
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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.forever(() => {
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let acceleration = input.acceleration(Dimension.Y);
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acceleration = Math.abs(acceleration)
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});
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```
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The function `acceleration(y)` returns a number between 0 and 1024. We want to use this value for the brightness of the micro:bit, but the `set brightness()` only accepts a value between 0 and 256. Thus, we need to divide the acceleration by 4 to ensure we will be in the appropriate range.
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```blocks
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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.forever(() => {
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let acceleration = input.acceleration(Dimension.Y);
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acceleration = Math.abs(acceleration);
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acceleration = acceleration / 4;
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});
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```
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Now let's use our acceleration value to set the brightness on the micro:bit.
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```blocks
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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.forever(() => {
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let acceleration = input.acceleration(Dimension.Y);
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acceleration = Math.abs(acceleration);
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acceleration = acceleration / 4;
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led.setBrightness(acceleration)
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});
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```
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### ~avatar avatar
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Excellent, you're ready to continue with the [challenges](/lessons/glowing-pendulum/challenges)!
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### ~
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