Arduino - PulseIn

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## unsigned long pulseIn(pin, value)

#### Description

Reads a pulse (either HIGH or LOW) on a pin. For example, if value is HIGH, pulseIn() waits for the pin to go HIGH, starts timing, then waits for the pin to go LOW and stops timing. Returns the length of the pulse in microseconds.

The timing of this function has been determined empirically and will probably show errors in longer pulses.Works on pulses from 10 microseconds to 3 minutes in length. Note that this function does not have a timeout built into it, so can appear to lock the Arduino if it misses the pulse.

#### Parameters

pin: the number of the pin on which you want to read the pulse. (int)

value: type type of pulse to read: either HIGH or LOW. (int)

#### Returns

the length of the pulse (in microseconds)

#### Example

    int pin = 7;
    unsigned long duration;

    void setup()
    {
      pinMode(pin, INPUT);
    }

    void loop()
    {
      duration = pulseIn(pin, HIGH);
    }

#### See also

- pinMode

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