83 lines
2.1 KiB
Markdown
83 lines
2.1 KiB
Markdown
# Compass Heading
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Find which direction on a compass the @boardname@ is facing.
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The @boardname@ measures the **compass heading** from `0` to `359`
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degrees with its **magnetometer** chip. Different numbers mean north,
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east, south, and west.
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```sig
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input.compassHeading();
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```
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## Returns
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* a [number](/types/number) from `0` to `359` degrees, which means the compass heading. If the compass isn't ready, it returns `-1003`.
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## Example
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This program finds the compass heading and stores it in the
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`degrees` variable.
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```blocks
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let degrees = input.compassHeading()
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```
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## ~hint
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When you run a program that uses this function in a browser, click and drag
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the compass needle on the screen to change the compass heading.
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## ~
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## Example: compass
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This program finds the compass heading and then shows a letter
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that means whether the @boardname@ is facing north (N), south (S),
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east (E), or west (W).
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```blocks
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let degrees = 0
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basic.forever(() => {
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degrees = input.compassHeading()
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if (degrees < 45) {
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basic.showArrow(ArrowNames.North)
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} else if (degrees < 135) {
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basic.showArrow(ArrowNames.East)
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} else if (degrees < 225) {
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basic.showArrow(ArrowNames.South)
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} else if (degrees < 315) {
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basic.showArrow(ArrowNames.West)
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} else {
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basic.showArrow(ArrowNames.North)
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}
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})
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```
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## Calibration
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Every time you start to use the compass (for example, if you have just turned the @boardname@ on),
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the @boardname@ will start a [calibrate compass](/reference/input/calibrate-compass)
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(adjust itself).
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The [calibration step](https://support.microbit.org/support/solutions/articles/19000008874-calibrating-the-micro-bit-compass)
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will ask you to draw a fill pattern on the screen by tilting the @boardname@.
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If you are calibrating or using the compass near metal, it might
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confuse the @boardname@.
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## ~ hint
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Keep the calibration handy by running it when the user pressed **A+B**.
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```block
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input.onButtonEvent(Button.AB, ButtonEvent.Click, () => {
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input.calibrateCompass();
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})
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```
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## ~
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## See also
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[acceleration](/reference/input/acceleration), [calibrate compass](/reference/input/calibrate-compass)
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