hydroponic-controller/include/ec.h

#ifndef _EC_H_
#define _EC_H_

#include <Arduino.h>

#define EC_PIN_RELAY_PROBE 27
#define EC_PIN_RELAY_RANGE 25


#define EC_PIN_ADC 4
#define EC_PIN_FREQ 5
#define EC_PWM_CH 0
#define EC_RESOLUTION 8
#define EC_FREQUENCY 5000

#define EC_ARRAY_SIZE 128
uint16_t ec_array_rangeLow[EC_ARRAY_SIZE];
uint16_t ec_array_rangeHigh[EC_ARRAY_SIZE];
uint16_t ec_array_pos=EC_ARRAY_SIZE*2;
#define EC_MEASUREMENT_INTERVAL 10000 //complete filtered measurement every x ms
  //One filtered measurement takes EC_READ_INTERVAL*EC_ARRAY_SIZE*2
#define EC_READ_INTERVAL 5 //interval of reading adc value inside a measurement

#define EC_RELAY_SWITCH_SETTLETIME 500  //time until voltage of ec circuit has settled

unsigned long ec_last_change_relay=0; //millis of last relay change

enum ECState{IDLE,MEASURE};

ECState ecstate=IDLE;


bool ec_measurementReady();
void ec_startMeasurement();
void ec_setRange(bool);
void ec_connectProbe(bool);
void ec_releaseRelay();

void ec_setup() {
  pinMode(EC_PIN_ADC,INPUT);

  ledcSetup(EC_PWM_CH, EC_FREQUENCY, EC_RESOLUTION);
  ledcAttachPin(EC_PIN_FREQ, EC_PWM_CH);
  ledcWrite(EC_PWM_CH, 127); //50% duty cycle

  pinMode(EC_PIN_RELAY_PROBE,OUTPUT); //LOW=Calibration/idle, HIGH=Probe connected
  pinMode(EC_PIN_RELAY_RANGE,OUTPUT); //LOW=NC Range Resistor, HIGH=NO Range Resistor
  ec_releaseRelay();

}

void ec_loop(unsigned long loopmillis) {
  static unsigned long last_measurement_ec=0;
  static unsigned long last_read_ec=0;

  switch (ecstate) {
    case IDLE:
      
      if (loopmillis>last_measurement_ec+EC_MEASUREMENT_INTERVAL && ecstate==IDLE) { //start measurement if idle
        last_measurement_ec=loopmillis;
        ec_startMeasurement();
        ec_connectProbe(true);
        ecstate=MEASURE;
        Serial.println("EC Take Measurement");
      }
      break;

    case MEASURE:
      if (ec_measurementReady()) {
        ec_releaseRelay();
        float adc_rangelow=getMean(ec_array_rangeLow,EC_ARRAY_SIZE);
        float adc_rangehigh=getMean(ec_array_rangeHigh,EC_ARRAY_SIZE);

        Serial.print("EC ADC: Low="); Serial.print(adc_rangelow); Serial.print(" High="); Serial.println(adc_rangehigh);

        ecstate=IDLE;
      }
      
      break;

  }



  if (loopmillis>last_read_ec+EC_READ_INTERVAL && ec_array_pos/2<EC_ARRAY_SIZE) { //take reading into array if measurement running
    last_read_ec=loopmillis;

    //flag_print= ec_array_pos==EC_ARRAY_SIZE;
    //ec_array_pos%=EC_ARRAY_SIZE;

    if (ec_array_pos<EC_ARRAY_SIZE){ //low range
      ec_setRange(LOW);
    }else{ //high range
      ec_setRange(HIGH);
    }

    if (loopmillis>ec_last_change_relay+EC_RELAY_SWITCH_SETTLETIME) { //values have settled
      uint16_t value=analogRead(EC_PIN_ADC);
      if (ec_array_pos<EC_ARRAY_SIZE){ //low range
        ec_array_rangeLow[ec_array_pos%EC_ARRAY_SIZE]=value;
        
      }else{ //high range
        ec_array_rangeHigh[ec_array_pos%EC_ARRAY_SIZE]=value;
        
      }

      
      /*
      if (ec_array_pos==0) {
        Serial.println(""); Serial.print("Lowrange:");
      }
      if (ec_array_pos==EC_ARRAY_SIZE) {
        Serial.println(""); Serial.print("Highrange:");
      }
      Serial.print(value); Serial.print(" ");
      if (ec_array_pos==EC_ARRAY_SIZE*2-1) {
        Serial.println("");
      }
      */
      
      
      ec_array_pos++;
    }
    
  }  
  
}



void ec_startMeasurement() {
  ec_array_pos=0;
}

bool ec_measurementReady(){
  if (ec_array_pos>=EC_ARRAY_SIZE*2) { //reached end of both arrays
    return true;
  }else{
    return false;
  }
}

void ec_setRange(bool range) {
  //range low means low resistor value -> NO -> relay High
  bool val=digitalRead(EC_PIN_RELAY_RANGE);
  if (val!=!range) { //write only if different
    digitalWrite(EC_PIN_RELAY_RANGE,!range);
    ec_last_change_relay=millis();
  }
}

void ec_connectProbe(bool relay) {
  bool val=digitalRead(EC_PIN_RELAY_PROBE);
  if (val!=relay) { //write only if different
    digitalWrite(EC_PIN_RELAY_PROBE,relay);
    ec_last_change_relay=millis();
  }
}

void ec_releaseRelay() {
  digitalWrite(EC_PIN_RELAY_PROBE,LOW);
  digitalWrite(EC_PIN_RELAY_RANGE,LOW);
  ec_last_change_relay=millis();
}


#endif