sender.ino

#include <MQ135.h>
#include <SimpleDHT.h>

int pinDHT11 = 2;
SimpleDHT11 dht11(pinDHT11);
/*  MQ135 gas sensor
    Datasheet can be found here: https://www.olimex.com/Products/Components/Sensors/SNS-MQ135/resources/SNS-MQ135.pdf

    Application
    They are used in air quality control equipments for buildings/offices, are suitable for detecting of NH3, NOx, alcohol, Benzene, smoke, CO2, etc

    Original creator of this library: https://github.com/GeorgK/MQ135
*/
//rf
#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>
RF24 radio(9, 10); // CE, CSN
const byte address[6] = "00001";     //Byte of array representing the address. This is the address where we will send the data. This should be same on the receiving side.

#define PIN_MQ135 A0

//end rf
MQ135 mq135_sensor(PIN_MQ135);

//structures
struct datareadings {
  int temperature;
  int humidity;
  float ppm;
};

void setup() {
  radio.begin();                  //Starting the Wireless communication
  radio.setChannel(35);
  radio.openWritingPipe(address); //Setting the address where we will send the data
  radio.setPALevel(RF24_PA_MAX);  //You can set it as minimum or maximum depending on the distance between the transmitter and receiver.
  radio.setDataRate(RF24_250KBPS);
  radio.stopListening();          //This sets the module as transmitter
  Serial.begin(9600);
}

void loop() {
  byte temperature = 0;
  byte humidity = 0;
  int err = SimpleDHTErrSuccess;
  if ((err = dht11.read(&temperature, &humidity, NULL)) != SimpleDHTErrSuccess) {
    //Serial.print("Read DHT11 failed, err="); Serial.println(err);delay(1000);
    return;
  }

  Serial.print("Sample OK: ");
  Serial.print((int)temperature); Serial.print(" *C, ");
  Serial.print((int)humidity); Serial.println(" H");
  float temp = ((int)temperature);
  float hum = ((int)humidity);

  float rzero = mq135_sensor.getRZero();
  float correctedRZero = mq135_sensor.getCorrectedRZero(temp, hum);
  float resistance = mq135_sensor.getResistance();
  float ppm = mq135_sensor.getPPM();
  float correctedPPM = mq135_sensor.getCorrectedPPM(temp, hum);

  Serial.print("MQ135 RZero: ");
  Serial.print(rzero);
  Serial.print("\t Corrected RZero: ");
  Serial.print(correctedRZero);
  Serial.print("\t Resistance: ");
  Serial.print(resistance);
  Serial.print("\t PPM: ");
  Serial.print(ppm);
  Serial.print("\t Corrected PPM: ");
  Serial.print(correctedPPM);
  Serial.println("ppm");
  datareadings A = {temp, humidity, ppm};
  Serial.println(A.temperature);
  radio.write(&A, sizeof(A));
  delay(300);
}