probe.cpp

#include "probe.h"

#ifndef DEBUG
#define DEBUG true
#endif

OneWire* probe::_myWire = 0;  // static member initialization
double probe::_sampleHz = 1;
boolean probe::_sampled = true;
unsigned long probe::_lastSample = 0;
unsigned int probe::_offset = 350;

void probe::init() {
  _myWire->reset();
  _myWire->skip();
  _myWire->write(0x44);
  _updateTemp();
  _temperature[1] = _temperature[2] = _temperature[3] = _temperature[0];
  _filter[0] = _filter[1] = _filter[2] = _filter[3] = _temperature[0];
}

void probe::startConv() {  //  initiate temperature conversion with _offset(ms) to temp/filter update
  if ((millis() >= (unsigned long)(_lastSample + _offset)) && _sampled) {
    _myWire->reset();
    _myWire->skip();
    _myWire->write(0x44);
    _sampled = false;
    #if DEBUG == true
      Serial.println(_offset);
    #endif
  }
}

boolean probe::isReady() {  //  initiate temperature and filter update with frequency = sampleHz
  if (millis() >= (unsigned long)(_lastSample + 1000/_sampleHz)) {  
    _lastSample = millis();
    _sampled = true;
    int wait = -1;
    do { wdt_reset(); wait++; } while (_isConv());
    #if DEBUG == true
      Serial.println(wait);
    #endif
    if (!wait) _offset++;
      else _offset--;
    return true;
  }
  return false;
}

void probe::update() {
  _updateTemp();
  _updateFilter();
}

boolean probe::_getAddr() {  // find next OneWire device, store rom address in probe struct
  _myWire->search(_address);
  if (OneWire::crc8(_address, 7) != _address[7]) return false;  // return false if crc check fails
  #if DEBUG == true
    Serial.print(F("New DS18B20 sensor found, addr:"));
    for (int i = 0; i < 6; i++) {
      Serial.print(_address[i], HEX);
      Serial.print(F(" "));
    }
    Serial.println(_address[7], HEX);
  #endif
  return true;
}

boolean probe::_updateTemp() {  // read OneWire device temperature
  byte data[9];
  _myWire->reset();
  _myWire->select(_address);
  _myWire->write(0xBE);
  for (int i = 0; i < 9; i++) data[i] = _myWire->read();
  if (OneWire::crc8(data, 8) != data[8]) return false;  // return false if crc check fails
  unsigned int raw = ((data[1] << 8) | data[0]); 
  byte cfg = (data[4] & 0x60);
  if (cfg == 0x00) raw = raw << 3;        // 9 bit res, 93.75 ms MAX conversion time
    else if (cfg == 0x20) raw = raw << 2; // 10 bit res, 187.5 ms MAX conversion time
    else if (cfg == 0x40) raw = raw << 1; // 11 bit res, 375 ms MAX conversion time
  for (int i = 3; i > 0; i--) {
    _temperature[i] = _temperature[i - 1];
  }
  _temperature[0] = ((data[1] << 8) | data[0]) / 16.0;  // default is 12 bit resolution, 750 ms MAX conversion time
    #if DEBUG == true
      Serial.print(F("Temperature:"));
      Serial.print(_temperature[0]);
      Serial.println(F(" read from sensor."));
    #endif
  return true;
}

void probe::_updateFilter() {  // update butterworth filter
  for (int i = 3; i > 0; i--) { _filter[i] = _filter[i - 1]; }

  _filter[0] = (_temperature[3] + _temperature[0] + 3 * (_temperature[2] + _temperature[1]))/1.092799972e+03
                      + (0.6600489526 * _filter[3]) + (-2.2533982563 * _filter[2]) + (2.5860286592 * _filter[1]);

  #if DEBUG == true
    for (int i = 0; i < 3; i++) { 
      Serial.print(_filter[i]); 
      Serial.print(F(" "));
    }
    Serial.println(_filter[3]);
  #endif
}

boolean probe::peakDetect() {  // detect negative peaks for fridge overshoot tuning
  if ((_filter[0] > _filter[1]) && (_filter[1] <= _filter[2])) return true;
  return false;
}

/*void updateSlowArrays() {  // update SlowFilter and temperature arrays using latest fast array data
  #if DEBUG == true
    Serial.print(F("slow update... "));
    Serial.print((unsigned long)(millis() - lastSlowSample));
    Serial.print(F("ms elapsed. "));
    Serial.print(lastFastSample);
    Serial.print(F(" "));
    Serial.print(lastSlowSample);
    Serial.print(F(" "));
    Serial.print(freeRAM());
    Serial.println(F(" bytes free SRAM remaining"));
  #endif
  
  lastSlowSample = millis();
  for (int i = 3; i > 0; i--) {
    T0_Slow[i] = T0_Slow[i - 1];
    T0_SlowFilter[i] = T0_SlowFilter[i - 1];
    
    T1_Slow[i] = T1_Slow[i - 1];
    T1_SlowFilter[i] = T1_SlowFilter[i - 1];
  }
  T0_Slow[0] = T0_Fast[0];  // update slow temperature; update Butterworth filter with cutoff frequency 0.01*sample frequency (FS=0.1Hz)
  T0_SlowFilter[0] = (T0_Slow[3] + T0_Slow[0] + 3 * (T0_Slow[2] + T0_Slow[1]))/3.430944333e+04
                      + (0.8818931306 * T0_SlowFilter[3]) + (-2.7564831952 * T0_SlowFilter[2]) + (2.8743568927 * T0_SlowFilter[1]);
  T1_Slow[0] = T1_Fast[0];
  T1_SlowFilter[0] = (T1_Slow[3] + T1_Slow[0] + 3 * (T1_Slow[2] + T1_Slow[1]))/3.430944333e+04
                      + (0.8818931306 * T1_SlowFilter[3]) + (-2.7564831952 * T1_SlowFilter[2]) + (2.8743568927 * T1_SlowFilter[1]);
  #if DEBUG == true
    for (int i = 0; i < 3; i++) {
      Serial.print(T0_SlowFilter[i]);
      Serial.print(F(" "));
    }
    Serial.println(T0_SlowFilter[3]);
  #endif
}*/