/* sensor vars and read functions */

//debounce time (milliseconds) between each analog sensor reading
const int sensorDebounceTime = 15;

int tmp102Address = 0x48; //temp sensor 2-wire address

CS_MQ7 MQ7(4);  //sensor "tog" pin on 4

void readSensors(){
  //sensors
  Serial.println("reading sensors");
  currNo2 = getNo2();
  delay(sensorDebounceTime);
  currCo = getCO();
  delay(sensorDebounceTime);
  currQuality = getQuality();
  delay(sensorDebounceTime);
  currHumidity = getHumidity();
  delay(sensorDebounceTime);
  currTemp = getTemperature();
  delay(sensorDebounceTime);

  MQ7.CoPwrCycler(); //for CO sensor power cycling
}

//--------- e2v MiCS-2170 NO2 sensor ---------
int getNo2(){
  int thisReading = 10;

  //set reference voltage to 3.3 here?
  thisReading = analogRead(No2SensorPin);
  return thisReading;
}

//--------- MQ-7 carbon monixide sensor ---------
//breakout info: http://citizensensor.cc/make
int getCO(){
  int thisReading = 11;

  if (MQ7.currentState() == LOW){ //not heating, ready to read.
    thisReading = analogRead(CoSensorPin);
  } 
  else { //heating, leave value where it was
    thisReading = currCo;
  }

  return thisReading;
}

//--------- MQ-135 air quality sensor ---------
int getQuality(){
  int thisReading = 12;

  thisReading = analogRead(qualitySensorPin);
  return thisReading;
}

//--------- DHT22 humidity sensor ---------
int getHumidity(){
  int thisReading = 13;

  //thisReading = analogRead(humiditySensorPin);

  float h = dht.readHumidity();

  if (isnan(h)){
    //failed to get reading from DHT
  } 
  else {
    thisReading = int(h);
    return thisReading;
  }
  return thisReading;
}

//--------- DHT22 temperature sensor ---------
int getTemperature(){
  int thisReading = 0;
  /*Wire.requestFrom(tmp102Address,2); 
   
   byte MSB = Wire.read();
   byte LSB = Wire.read();
   
   //it's a 12bit int, using two's compliment for negative
   int TemperatureSum = ((MSB << 8) | LSB) >> 4; 
   
   float celsius = TemperatureSum*0.0625;
   
   thisReading = int(celsius);
   */
  float t = dht.readTemperature();

  if (isnan(t)){
    //failed to get reading from DHT
  } 
  else {
    thisReading = int(t);
    return thisReading;
  }
}