sensoresp/include/sensor_sds018.cpp

#include "sensor_sds018.h"

// SDS018 example: https://github.com/crystaldust/sds018/blob/master/sds018.ino

//SDS18 dust sensor for 2.5µm and 10µm
//Needs 5V


Sensor_SDS018::Sensor_SDS018(int prx,int ptx)
{
  pin_rx=prx;
  pin_tx=ptx;

  sds018_swSerial = new SoftwareSerial();
}

void Sensor_SDS018::init() //Things to be done during setup()
{    
  Serial.println("initializing sds018");
  sds018_swSerial->begin(BAUD_RATE_SDS018, SWSERIAL_8N1, pin_rx, pin_tx, false, 256);
  init_ok=true;
}

//Also called during setup()
void Sensor_SDS018::setSettings_pm10(float minchange, unsigned long senddelaymax, unsigned long readdelay)
{
    data_pm10.minchange=minchange;
    data_pm10.senddelaymax=senddelaymax;
    data_pm10.readdelay=readdelay;
}

void Sensor_SDS018::setSettings_pm25(float minchange, unsigned long senddelaymax, unsigned long readdelay)
{
    data_pm25.minchange=minchange;
    data_pm25.senddelaymax=senddelaymax;
    data_pm25.readdelay=readdelay;
}



//Called during setup
void Sensor_SDS018::advertise(HomieNode& p_sensorNode)
{
    sensorNode = &p_sensorNode;
    sensorNode->advertise("dust_pm25");
    sensorNode->advertise("dust_pm10");
}

void Sensor_SDS018::sensorloop()
{
  if (init_ok) {
    loop_pm10();
    loop_pm25();
  }
}


void Sensor_SDS018::loop_pm25()
{
  sensordata &d=data_pm25;

  bool _changed=false;
  if (millis() >= (d.lastreadtime+d.readdelay)) {
    if (millis() >= (lastread_sds018+d.readdelay)) {
      readSDS018(); //reads values into data_pm10 and data_pm25
    }
    if (fabs(d.lastsentvalue-d.value)>=d.minchange){
      _changed=true;
    }
    d.lastreadtime=millis();
  }

  if (_changed || millis() >= (d.lastsent+d.senddelaymax)) {
    Serial.print("Sending SDS018_pm25. reason=");
    if (_changed) Serial.println("change"); else Serial.println("time");

    Homie.getLogger() << "read pm25: " << d.value << " status=" << sds018_dustok << endl;
    if (sds018_dustok){ //send no dust values if sensor not ok
      sensorNode->setProperty("dust_pm25").send(String(d.value));
    }else{
      Homie.getLogger() << "sds018 dust not ok. didnt sent" << endl;
    }
    
    d.lastsentvalue=d.value;
    
    d.lastsent=millis();
  }
}
void Sensor_SDS018::loop_pm10()
{
  sensordata &d=data_pm10;

  bool _changed=false;
  if (millis() >= (d.lastreadtime+d.readdelay)) {
    if (millis() >= (lastread_sds018+d.readdelay)) {
      readSDS018(); //reads values into data_pm10 and data_pm25
    }
    if (fabs(d.lastsentvalue-d.value)>=d.minchange){
      _changed=true;
    }
    d.lastreadtime=millis();
  }

  if (_changed || millis() >= (d.lastsent+d.senddelaymax)) {
    Serial.print("Sending SDS018_pm10. reason=");
    if (_changed) Serial.println("change"); else Serial.println("time");
    
    Homie.getLogger() << "read pm10: " << d.value << " status=" << sds018_dustok << endl;
    if (sds018_dustok){ //send no dust values if sensor not ok
      sensorNode->setProperty("dust_pm10").send(String(d.value));
    }else{
      Homie.getLogger() << "sds018 dust not ok. didnt sent" << endl;
    }
    
    d.lastsentvalue=d.value;
    
    d.lastsent=millis();
  }
}

void Sensor_SDS018::readSDS018() 
{
  lastread_sds018=millis();
  // https://github.com/crystaldust/sds018/blob/master/sds018.ino
  uint8_t mData = 0;
  uint8_t mPkt[10] = {0};
  uint8_t mCheck = 0;
  while( sds018_swSerial->available() > 0 ) {
    //Serial.println("serial available");
    for( int i=0; i<10; ++i ) {
      mPkt[i] = sds018_swSerial->read();
      //Serial.println( mPkt[i], HEX );
    }
    if( 0xC0 == mPkt[1] ) {
      Serial.println("read density");
      // Read dust density.
      // Check
      uint8_t sum = 0;
      for( int i=2; i<=7; ++i ) {
        sum += mPkt[i];
      }
      if( sum == mPkt[8] ) {
        uint8_t pm25Low   = mPkt[2];
        uint8_t pm25High  = mPkt[3];
        uint8_t pm10Low   = mPkt[4];
        uint8_t pm10High  = mPkt[5];
  
        data_pm25.value = ( ( pm25High * 256.0 ) + pm25Low ) / 10.0;
        data_pm10.value = ( ( pm10High * 256.0 ) + pm10Low ) / 10.0;

        sds018_dustok=true;
      }
    }
    
    sds018_swSerial->flush();
  }
}