#include <HardwareSerial.h>

// กำหนดพอร์ต Serial ของ ESP32
HardwareSerial mySerial(1); // ใช้พอร์ต Serial 1 (TX: GPIO 17, RX: GPIO 16)

unsigned int pm1 = 0;
unsigned int pm2_5 = 0;
unsigned int pm10 = 0;

void setup() {
  Serial.begin(115200); // Serial Monitor (USB Serial)
  mySerial.begin(9600, SERIAL_8N1, 16, 17); // กำหนด baud rate, RX, TX สำหรับ Serial 1

  Serial.println("ESP32 PM Sensor Reading...");
}

void loop() {
  int index = 0;
  char value;
  char previousValue;

  if (mySerial.available()) {
    while (mySerial.available()) {
      value = mySerial.read();
      
      if ((index == 0 && value != 0x42) || (index == 1 && value != 0x4d)) {
        Serial.println("Cannot find the data header.");
        break;
      }

      if (index == 4 || index == 6 || index == 8 || index == 10 || index == 12 || index == 14) {
        previousValue = value;
      }
      else if (index == 5) {
        pm1 = 256 * previousValue + value;
        Serial.print("{ ");
        Serial.print("\"pm1\": ");
        Serial.print(pm1);
        Serial.print(" ug/m3");
        Serial.print(", ");
      }
      else if (index == 7) {
        pm2_5 = 256 * previousValue + value;
        Serial.print("\"pm2_5\": ");
        Serial.print(pm2_5);
        Serial.print(" ug/m3");
        Serial.print(", ");
      }
      else if (index == 9) {
        pm10 = 256 * previousValue + value;
        Serial.print("\"pm10\": ");
        Serial.print(pm10);
        Serial.print(" ug/m3");
      } 
      else if (index > 15) {
        break;
      }
      index++;
    }

    while (mySerial.available()) mySerial.read(); // ล้างข้อมูลค้างใน buffer
    Serial.println(" }");
  }

  delay(1000);
}