hydroponic-controller/include/waterlevel_hcsr04.h

#ifndef _WATERLEVEL_H_
#define _WATERLEVEL_H_


#include <HCSR04.h>
#define HCSR04_PIN_ECHO 17
#define HCSR04_PIN_TRIGGER 16
#define HCSR04_TIMEOUT 5000 //default is 100000 (uS)
#define READINTERVAL_HCSR04 200

#define WATERLEVELMEAN_SIZE 32
#define WATERLEVELMEAN_FILTER_CUTOFF 8 //max value is around WATERLEVELMEAN_SIZE/2
float waterlevelMean_array[WATERLEVELMEAN_SIZE];
uint16_t waterlevelMean_array_pos=0;
#define WATERLEVEL_UNAVAILABLE -1
float waterlevel=WATERLEVEL_UNAVAILABLE;  //distance from floor to water surface [mm]
float watervolume=WATERLEVEL_UNAVAILABLE; //calculated Volume in Reservoir

uint16_t waterlevel_failcounter=0;
#define WATERLEVEL_MAXFAILS 15 //maximum counter value
#define WATERLEVEL_FAILTHRESHOLD 10 //if failcounter is greater or equal this value waterlevel will not be valid

//Calibration
float waterlevel_calib_offset_measured=0; //Sollwert
float waterlevel_calib_offset_sensor=178.67; //Istwert

float waterlevel_calib_reservoirArea=27*36.5; //area in cm^2


float waterlevel_heightToVolume(float distance);


void waterlevel_setup() {

  //HCSR04.begin(HCSR04_PIN_TRIGGER, HCSR04_PIN_ECHO);
  HCSR04.begin(HCSR04_PIN_TRIGGER, HCSR04_PIN_ECHO,HCSR04_TIMEOUT, HCSR04.eUltraSonicUnlock_t::unlockSkip);
  for (uint16_t i=0;i<WATERLEVELMEAN_SIZE;i++) {
    waterlevelMean_array[i]=-1; //-1 is also timeout value
    
  }
}

void waterlevel_loop(unsigned long loopmillis) {

  static unsigned long last_read_hcsr04;
  if (loopmillis>=last_read_hcsr04+READINTERVAL_HCSR04) {
    last_read_hcsr04=loopmillis;
    float temperature=20.0;
    if (tempCmean_air!=DEVICE_DISCONNECTED_C) { //sensor ok
      temperature=tempCmean_air;
    }
    
    double* distances = HCSR04.measureDistanceMm(temperature);
    double distance=distances[0];
    //Serial.print("Distance reading:"); Serial.println(distance);

    if (distance!=WATERLEVEL_UNAVAILABLE) { //successful
      waterlevelMean_array[waterlevelMean_array_pos]=distance;
      waterlevelMean_array_pos++;
      waterlevelMean_array_pos%=WATERLEVELMEAN_SIZE;
      if (waterlevel_failcounter>0) { //reduce failcounter if sucessfull
        waterlevel_failcounter--;
      }
    }else{
      if (waterlevel_failcounter<WATERLEVEL_MAXFAILS) {
        waterlevel_failcounter++;
      }
      
    }

    
    if (isValueArrayOKf(waterlevelMean_array,WATERLEVELMEAN_SIZE,WATERLEVEL_UNAVAILABLE)){
      //float _distance=getFilteredf(waterlevelMean_array,WATERLEVELMEAN_SIZE,WATERLEVELMEAN_FILTER_CUTOFF);
      float _distance=getMaxf(waterlevelMean_array,WATERLEVELMEAN_SIZE);

      //Invert distance and offset
      waterlevel=distance-(waterlevel_calib_offset_sensor+waterlevel_calib_offset_measured);
      watervolume=waterlevel_heightToVolume(_distance);

      //float _meanWaterlevel=getMeanf(waterlevelMean,WATERLEVELMEAN_SIZE);
      //Serial.print("\t Dist="); Serial.print(_filteredWaterlevel); Serial.print("mm"); Serial.print("(+- "); Serial.print((getMaxf(waterlevelMean,WATERLEVELMEAN_SIZE)-getMinf(waterlevelMean,WATERLEVELMEAN_SIZE))/2.0); Serial.print(")"); Serial.print(" [mean="); Serial.print(_meanWaterlevel); Serial.print("]"); 
    }

    if (waterlevel_failcounter>=WATERLEVEL_FAILTHRESHOLD) { //too many failed readings
      waterlevel=WATERLEVEL_UNAVAILABLE;
      watervolume=WATERLEVEL_UNAVAILABLE;
      /*if (debug) {
        Serial.print("Waterlevel Failcounter="); Serial.println(waterlevel_failcounter);
      }*/
    }

  }
}

float waterlevel_heightToVolume(float distance){
  return waterlevel_calib_reservoirArea/100 * distance/100; //area[cm^2] in dm^2 * height in dm = dm^3= L
}

#endif