Peli de Halleux bd895f43ba Calibrate compass (#392 )

* adding 'calibrate-compass' function

* fixing simulator.

* updated docs

* fixing compat test suite with 'calibrate()' function

2017-04-25 10:46:25 -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.

input.compassHeading();

Returns

a 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.

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).

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 calibrateCompass (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@.

~ hint

Keep the calibration handy by running it when the user pressed A+B.

input.onButtonPressed(Button.AB, () => {
    input.calibrateCompass();
})

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