55 lines
1.4 KiB
Markdown
55 lines
1.4 KiB
Markdown
# Pulse In
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Returns the duration of a pulse (high or low) from a [pin](/device/pins) on
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the micro:bit board in microseconds.
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```sig
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pins.pulseIn(DigitalPin.P0, PulseValue.High)
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```
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### ~avatar
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Some pins are also used by the [LED screen](/device/screen).
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Please read the [page about pins](/device/pins) carefully.
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### ~
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### Parameters
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* ``name`` is a [string](/reference/types/string) that stores the name of the pin (``P0``, ``P1``, or ``P2``, up through ``P20``)
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* ``value`` is the value of the pulse, ``high`` or ``low``
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* ``maxDuration``, maximum duration in micro-seconds. If no pulse is received
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### Returns
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* a [number](/reference/types/number) that represents the pulse duration in micro-seconds
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### Example: Measuring distance with a sonar
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The following script sends a pulse on ``P0`` and reads the pulse returned by a HC-SR04 sonar to determine the distance of the object in front of the sensor.
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```blocks
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basic.forever(() => {
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// send pulse
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pins.digitalWritePin(DigitalPin.P0, 0)
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control.waitMicros(2)
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pins.digitalWritePin(DigitalPin.P0, 1)
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control.waitMicros(10)
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pins.digitalWritePin(DigitalPin.P0, 0)
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// read pulse
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led.plotBarGraph(pins.pulseIn(DigitalPin.P1, PulseValue.High) / 58, 0)
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basic.pause(100)
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})
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```
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#### ~hint
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This function is not supported in the simulator.
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#### ~
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### See also
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[digital write pin](/reference/pins/digital-write-pin),
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