ESP32_AWS.ino

#include<WiFi.h>
#include<AWS_IOT.h>
#include <Wire.h>
#include <PubSubClient.h>
#include <HardwareSerial.h>
#define WIFI_SSID "xxxxx" // your wifi ssid
#define WIFI_PASSWD "xxxxx" //your wifi password

#define CLIENT_ID "xxxxx"// thing unique ID, can be any unique id
#define MQTT_TOPIC "xxxxxx" //topic for the MQTT data
#define AWS_HOST "xxxxxx" // your host for uploading data to AWS,
uint8_t data[29];
int k = 10;
int i;
int temp;
int Humidity;
char payload[40];
AWS_IOT aws;

void setup() {
  Serial.println(WIFI_SSID);
  WiFi.begin(WIFI_SSID, WIFI_PASSWD);
  Serial1.begin(115200, SERIAL_8N1, 16, 17); // pins 16 rx2, 17 tx2, 19200 bps, 8 bits no parity 1 stop bit​
  Serial.begin(9600);
  Serial.println("ncd.io IoT ESP32 Temperature and Humidity sensor");

  Serial.print("\n  Initializing WIFI: Connecting to ");

  Serial.print("  ");
  while (WiFi.status() != WL_CONNECTED) {
    Serial.print(".");
    delay(500);
  }
  Serial.println("\n  Connected.\n  Done");



  Serial.println("\n  Initializing connetction to AWS....");
  if (aws.connect(AWS_HOST, CLIENT_ID) == 0) { // connects to host and returns 0 upon success
    Serial.println("  Connected to AWS\n  Done.");
  }
  else {
    Serial.println("  Connection failed!");
  }
  Serial.println("  Done.\n\nDone.\n");
}

void loop() {
  // read temperature and humidity
  if (Serial1.available())
  {
    data[0] = Serial1.read();
    delay(k);
    if (data[0] == 0x7E)
    {
      while (!Serial1.available());
      for ( i = 1; i < 29; i++)
      {
        data[i] = Serial1.read();
        delay(1);
      }
      if (data[15] == 0x7F) /////// to check if the recive data is correct
      {
        if (data[22] == 1) //////// make sure the sensor type is correct
        {
          float humidity = ((((data[24]) * 256) + data[25]) / 100.0);
          int16_t cTempint = (((uint16_t)(data[26]) << 8) | data[27]);
          float cTemp = (float)cTempint / 100.0;
          float fTemp = cTemp * 1.8 + 32;
          float battery = ((data[18] * 256) + data[19]);
          float voltage = 0.00322 * battery;
          Serial.print("Sensor Number  ");
          Serial.println(data[16]);
          Serial.print("Sensor Type  ");
          Serial.println(data[22]);
          Serial.print("Firmware Version  ");
          Serial.println(data[17]);
          Serial.print("Relative Humidity :");
          Serial.print(humidity);
          Serial.println(" %RH");
          Serial.print("Temperature in Celsius :");
          Serial.print(cTemp);
          Serial.println(" C");
          Serial.print("Temperature in Fahrenheit :");
          Serial.print(fTemp);
          Serial.println(" F");
          Serial.print("ADC value:");
          Serial.println(battery);
          Serial.print("Battery Voltage:");
          Serial.print(voltage);
          Serial.println("\n");
          if (voltage < 1)
          {
            Serial.println("Time to Replace The Battery");
          }
          temp = cTemp;
          Humidity = humidity;
        }
      }
      else
      {
        for ( i = 0; i < 29; i++)
        {
          Serial.print(data[i]);
          Serial.print(" , ");
          delay(1);
        }
      }
    }
  }

  // check whether reading was successful or not
  if (temp == NAN || Humidity == NAN) { // NAN means no available data
    Serial.println("Reading failed.");
  }
  else {
    //create string payload for publishing
    String temp_humidity = "Temperature: ";
    temp_humidity += String(temp);
    temp_humidity += " °C Humidity: ";
    temp_humidity += String(Humidity);
    temp_humidity += " %";


    temp_humidity.toCharArray(payload, 40);

    Serial.println("Publishing:- ");
    Serial.println(payload);
    if (aws.publish(MQTT_TOPIC, payload) == 0) { // publishes payload and returns 0 upon success
      Serial.println("Success\n");
    }
    else {
      Serial.println("Failed!\n");
    }
  }

  delay(1000);
}