MQ131 won't work with other sensors

Projects Programming
1

So far i tried to combine multiple sensors but i couldnt combine mq131 ozone with others.

#include <MQ131.h>

// Define the serial port for MH-Z19B sensor (Serial2 on Arduino Mega)
#define MHZ19B_SERIAL Serial2

// Define the serial port for Bluetooth (Serial3 on Arduino Mega)
#define BLUETOOTH_SERIAL Serial3

// Define the baud rate for MH-Z19B sensor
#define MHZ19B_BAUDRATE 9600

// Define the command to read CO2 concentration
uint8_t MHZ19B_CMD_READ_CO2[] = {0xFF, 0x01, 0x86, 0x00, 0x00, 0x00, 0x00, 0x00, 0x79};




void setup() {
  // Initialize Serial Monitor for debugging
  BLUETOOTH_SERIAL.begin(9600);
  Serial.begin(9600);
  Serial1.begin(9600); // For PMS5003
  MHZ19B_SERIAL.begin(MHZ19B_BAUDRATE);

  MQ131.begin(3, A7, LOW_CONCENTRATION, 1000000);
  Serial.println("Calibration in progress..."); 
  MQ131.calibrate();
  MQ131.getR0();
  MQ131.getTimeToRead();
  Serial.println("Calibration done!");


}




void readCO2() {
  // Send command to MH-Z19B sensor to read CO2 concentration
  MHZ19B_SERIAL.write(MHZ19B_CMD_READ_CO2, sizeof(MHZ19B_CMD_READ_CO2));
  
  // Read response from the sensor
  uint8_t response[9];
  MHZ19B_SERIAL.readBytes(response, 9);
  
  // Check if response is valid
  if (response[0] == 0xFF && response[1] == 0x86) {
    // Calculate CO2 concentration (high byte * 256 + low byte)
    int co2 = response[2] * 256 + response[3];
    
    // Print CO2 concentration to Serial Monitor
    Serial.print("CO2 Level: ");
    Serial.print(co2);
    Serial.println(" ppm");

    BLUETOOTH_SERIAL.print(co2);
    BLUETOOTH_SERIAL.print("ppm");
    BLUETOOTH_SERIAL.print(",");
  } else {
    // Print error if response is invalid
    Serial.println("Error: Invalid response from sensor");
  }
}

void readozon() {

  MQ131.sample();

  Serial.print(MQ131.getO3(UG_M3));
  BLUETOOTH_SERIAL.print(MQ131.getO3(UG_M3));
  BLUETOOTH_SERIAL.print("ug/m3");
  BLUETOOTH_SERIAL.print(";");

}

void loop() {
  

  readCO2();

  delay(2000);

  readozon();

  delay(2000);
    
}

After I upload the code, i only get this.

19:21:15.986 -> Calibration in progress...

First i tried to power it up through arduino. After that i hooked it up externally and still won't work. But if i use it alone , it has no problem ( on my uno). I'm kinda done. I found no solution whatsoever. The external source is 9V @ 1A which goes through a dc-dc buck converter and i get 5V so there's no way the problem is on the electrical side. Also, it s the module sensor, not the raw one. The schematic is this:
licenta.pdf (130.2 KB)
Also , the code pins on my sketch aren't the same as my schematic (I mean this code MQ131.begin(3, A7, LOW_CONCENTRATION, 1000000); ) since I had problems with mq131 and i desperately tried to change the pinout of mq131. Same goes with the co2 sensor.

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