485.ino

/* Dev by IOXhop.com */

//#define DE_RE_PIN 4
#define MODE_SEND HIGH
#define MODE_RECV LOW

float temp = 0, humi = 0;

void readXY_MD02() {
  uint8_t buff[] = {
    0x01, // Devices Address
    0x03, // Function code
    0x01, // Start Address HIGH
    0xF8, // Start Address LOW
    0x00, // Quantity HIGH
    0x02, // Quantity LOW
    0x44, // CRC LOW
    0x06  // CRC HIGH
  };
  //  digitalWrite(DE_RE_PIN, MODE_SEND);
  Serial2.write(buff, sizeof(buff));
  Serial2.flush(); // wait send completed
  //  digitalWrite(DE_RE_PIN, MODE_RECV);

  if (Serial2.find("\x01\x04")) {
    uint8_t n = Serial2.read();
    if (n != 4) {
      Serial.println("Error data size");
      return;
    }

//    temp = ((uint16_t)(Serial2.read() << 8) | Serial2.read()) / 10.0;
//    humi = ((uint16_t)(Serial2.read() << 8) | Serial2.read()) / 10.0;

    temp = ((uint16_t)(Serial2.read() << 8) | Serial2.read()) / 10.0;
    humi = ((uint16_t)(Serial2.read() << 8) | Serial2.read()) / 10.0;
  } else {
    Serial.println("ERROR Timeout");
    return;
  }
}

void setup() {
  //  pinMode(DE_RE_PIN, OUTPUT);
  //  digitalWrite(DE_RE_PIN, MODE_RECV);

  Serial.begin(115200);

  Serial2.begin(4800, SERIAL_8N1, 16, 17); // Rx, Tx
  Serial2.setTimeout(200);
}

void loop() {
  readXY_MD02();
  Serial.print("Temperature: ");
  Serial.print(temp);
  Serial.println(" *C");
  Serial.print("Humidity: ");
  Serial.print(humi);
  Serial.println(" *C");
  delay(500);
}