first re-commit.

pigsonar.cpp

@@ -0,0 +1,215 @@
+/*****************************************************************************
+
+    source::worx libPiGPio
+    Copyright © 2022 c.holzheuer
+    chris@sourceworx.org
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    Uses:
+
+    pigpiod_if2 by joan2937, pigpio @ abyz.me.uk
+    https://abyz.me.uk/rpi/pigpio
+
+    sigslot  by 2017 Pierre-Antoine Lacaze
+    https://github.com/palacaze/sigslot
+
+    pigSonar based on: https://github.com/OmarAflak/HC-SR04-Raspberry-Pi-C-
+
+***************************************************************************/
+
+
+#include <pigsonar.h>
+#include <iostream>
+
+/**
+ * @brief pigSonar::pigSonar
+ *
+ *
+ * Beschreibung HC-SR04:
+ * Das Ultraschall Modul HC-SR04 eignet sich zur
+ * Entfernungsmessung im Bereich zwischen 2cm und ca.
+ * 3m mit einer Auflösung von 3mm. Es benötigt nur eine
+ * einfache Versorgungsspannung von 5V bei einer
+ * Stromaufnahme von <2mA. Nach Triggerung mit einer
+ * fallenden Flanke (TTL - Pegel) misst das Modul
+ * selbstständig die Entfernung und wandelt diese in ein
+ * PWM Signal welches am Ausgang zur Verfügung steht.
+ * Ein Messintervall hat eine Dauer von 20ms. Es können
+ * also 50 Messungen pro Sekunde durchgeführt werden
+ *
+ * https://www.mikrocontroller.net/attachment/218122/HC-SR04_ultraschallmodul_beschreibung_3.pdf
+ */
+
+pigSonar::pigSonar()
+{
+
+}
+
+
+pigSonar::pigSonar( pigpio::bcm_t trigger, pigpio::bcm_t echo )
+{
+    init( trigger, echo );
+}
+
+
+pigSonar::~pigSonar()
+{
+    //detach_pin( ) //?? doch wg .callback
+}
+
+
+void pigSonar::init( pigpio::bcm_t trigger, pigpio::bcm_t echo )
+{
+
+    _pinEcho.init( echo );
+    //_pinEcho.set_callback( this, rising );
+
+    _pinTrig.init( trigger );
+    _pinTrig.set_level( low );
+
+    delay_millis( 500 );
+
+}
+
+void pigSonar::stop()
+{
+    _active = false;
+}
+
+void pigSonar::start( double thresh )
+{
+    _active = true;
+    std::thread thrd(
+    [=]()
+    {
+        while( _active  )
+        {
+            double dist = distance();
+            if( dist < thresh )
+                sigValue( dist );
+            delay_millis( 50 );
+        }
+
+    } );
+    thrd.detach();
+
+}
+
+
+double pigSonar::distance( int timeout )
+{
+
+    // erholungspause
+    delay_millis( 10 );
+
+    // ein 10 ms pulse löst die messung aus
+    _pinTrig.set_level( high );
+    delay_micros( 10 );
+    _pinTrig.set_level( low );
+
+    //_timer.start();
+    _now = get_current_tick();
+    // busy waiting ??
+    while ( _pinEcho.get_level() == low && _timer.elapsed_millis() < timeout )
+    //while ( _pinEcho.get_level() == low )
+        ;
+
+    //_timer.start();
+    _now = get_current_tick();
+    while( _pinEcho.get_level() == high )
+        ;
+
+    uint32_t tof = get_current_tick() - _now;
+    //double tof = _timer.elapsed_micros();
+    _dist = 100 * ( ( tof /1000000.0 ) * 340.29 ) / 2;
+
+    return _dist;
+}
+
+/*
+void pigSonar::trigger( pigpio::bcm_t bcm, uint32_t level )
+{
+    double duration = _timer.elapsed_micros();
+    // Convert the time into a distance
+    _dist = (duration/2) / 29.1;     // Divide by 29.1 or multiply by 0.0343
+    //double inches = (duration/2) / 74;   // Divide by 74 or multiply by 0.0135
+
+}
+*/
+
+/**
+
+  Die Variante mit WiringPi ist erheblich genauer. Warum? Timer?
+  Code: https://github.com/OmarAflak/HC-SR04-Raspberry-Pi-C-
+
+  dort:
+
+    Distance is 27.4614 cm.
+    Distance is 27.4614 cm.
+    Distance is 27.4614 cm.
+    Distance is 27.4614 cm.
+    Distance is 27.4784 cm.
+    Distance is 27.4784 cm.
+    Distance is 27.4614 cm.
+    Distance is 27.4784 cm.
+    Distance is 27.4614 cm.
+    Distance is 27.4784 cm.
+    Distance is 27.4614 cm.
+    Distance is 27.4784 cm.
+    Distance is 27.4614 cm.
+
+  hier (busy wait):
+
+     distance: 28.21
+     distance: 25.9811
+     distance: 28.3121
+     distance: 28.2441
+     distance: 28.4482
+     distance: 27.9889
+     distance: 28.0569
+     distance: 28.0059
+     distance: 28.2441
+     distance: 25.3346
+     distance: 28.0059
+     distance: 29.0608
+     distance: 27.9718
+     distance: 28.0399
+     distance: 27.9889
+
+
+Die eigene Variante _ohne_ busy wating mit callback ist logischerweise
+auch nicht besser.
+
+double Sonar::distance(int timeout)
+{
+    delay(10);
+
+    digitalWrite(trigger, HIGH);
+    delayMicroseconds(10);
+    digitalWrite(trigger, LOW);
+
+    now=micros();
+
+    while (digitalRead(echo) == LOW && micros()-now<timeout)
+        ;
+    recordPulseLength();
+
+    travelTimeUsec = endTimeUsec - startTimeUsec;
+    distanceMeters = 100*((travelTimeUsec/1000000.0)*340.29)/2;
+
+    return distanceMeters;
+}
+
+void Sonar::recordPulseLength()
+{
+    startTimeUsec = micros();
+    while ( digitalRead(echo) == HIGH )
+        ;
+    endTimeUsec = micros();
+}
+
+*/