pxt-calliope/docs/reference/input/compass-heading.md
2016-11-01 17:44:37 -07:00

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# Compass Heading
Find which direction on a compass the @boardname@ is facing.
The @boardname@ measures the **compass heading** from `0` to `360`
degrees with its **magnetometer** chip. Different numbers mean north,
east, south, and west.
```sig
input.compassHeading();
```
### Returns
* a [number](/reference/types/number) from `0` to `360` degrees, which means the compass heading. If the compass isn't ready, it returns `-1003`.
### Example
This program finds the compass heading and stores it in the
`degrees` variable.
```blocks
let degrees = input.compassHeading()
```
### ~hint
When you run a program that uses this function in a browser, click and drag
the compass needle on the screen to change the compass heading.
### ~
### Example: compass
This program finds the compass heading and then shows a letter
that means whether the @boardname@ is facing north (N), south (S),
east (E), or west (W).
```blocks
basic.forever(() => {
let degrees = input.compassHeading()
if (degrees < 45)
basic.showString("N")
else if (degrees < 135)
basic.showString("E")
else if (degrees < 225)
basic.showString("S")
else basic.showString("W")
})
```
### Calibration
Every time you start to use the compass (for example, if you have just
turned the @boardname@ on), the @boardname@ will start to **calibrate**
(adjust itself). It will ask you to draw a circle by tilting the
@boardname@.
If you are calibrating or using the compass near metal, it might
confuse the @boardname@.
### See also
[acceleration](/reference/input/acceleration)