Code

#include <Adafruit_PM25AQI.h>

// Pin definitions

#define THERMISTOR_PIN A0 // Analog pin for the thermistor

#define PRESSURE_PIN A1 // Analog pin for the pressure sensor

Adafruit_PM25AQI aqi;

// Variables for temperature, pressure, and altitude

float temperature; // Temperature in degrees Celsius

float pressure; // Pressure in millibars

float altitude; // Altitude in meters

void setup() {

Serial.begin(9600);

while (!Serial) {

delay(10);

}

// Initialize PM2.5 sensor communication

if (!aqi.begin_UART(&Serial)) {

Serial.println("Could not find PM2.5 sensor, check wiring!");

while (1);

}

void loop() {

// Read analog voltage from thermistor

int sensorValue = analogRead(THERMISTOR_PIN);

float voltage = sensorValue * (5.0 / 1023.0); // Convert raw value to voltage

temperature = voltage * (-16.343) + 49.544; // Convert voltage to temperature in Celsius

// Read pressure value from pressure sensor

int pressureValue = analogRead(PRESSURE_PIN);

pressure = ((pressureValue / 1024.0) + 0.095) / 0.0009; // Convert pressure value to millibars

// Calculate altitude using the formula with updated air density

float P0 = 101325; // Standard pressure at sea level in Pa

float rho = 1.2690; // Density of air at 5°C and sea level in kg/m^3

float g = 9.81; // Acceleration due to gravity in m/s^2

float P = pressure * 100; // Convert pressure to Pascals

altitude = (P - P0) / (rho * g); // Calculate altitude

// Read PM2.5 sensor data

PM25_AQI_Data data;

if (!aqi.read(&data)) {

Serial.println("Could not read from PM2.5 sensor");

delay(500);

return;

}

// Print temperature, pressure, and altitude

Serial.print("TEMPERATURE = ",temperature," C");