qEcho/source/distancethread.cpp

#include "distancethread.h"
#include <wiringPi.h>

volatile unsigned int timestampHigh = 0;
volatile unsigned int pulseLength = 0;

DistanceThread::DistanceThread()
{
    wiringPiSetup();
    pinMode(m_triggerPin, OUTPUT);
    pinMode(m_echoPin, INPUT);
}

void DistanceThread::run()
{
    wiringPiISR(m_echoPin, INT_EDGE_BOTH, []
    {
        if (digitalRead(29) == HIGH)
        {
            timestampHigh = micros();
        }
        else if (timestampHigh != 0)
        {
			pulseLength = micros() - timestampHigh;
			timestampHigh = 0;
        }
    });

    while (true)
    {
        digitalWrite(m_triggerPin, HIGH);
        delayMicroseconds(10);
        digitalWrite(m_triggerPin, LOW);
        delayMicroseconds(40);

        if (pulseLength < 25e3)
        {
            emit distanceUpdated(pulseLength / 0.58);
        }

        delay(100);
    }
}