Complete Guide to Remote WiFi Thermostat Modules

				
					#include <WiFi.h>
#include <PubSubClient.h>
#include <Adafruit_SHT3x.h>

// WiFi configuration
const char* ssid = "Your WiFi Name";       // Replace with your home/commercial WiFi name
const char* password = "Your WiFi Password"; // Replace with your WiFi password
const char* mqttBroker = "mqtt.thingsboard.io"; // Cloud MQTT broker address
const char* mqttUsername = "Your Device Token"; // Cloud platform device ID/token
const char* mqttPassword = "";           // No password required for some platforms, leave blank
const int mqttPort = 1883;               // MQTT default port

// Pin definitions
const int relayPin = 4;                  // Relay control pin on the module
Adafruit_SHT3x sht30 = Adafruit_SHT3x(); // SHT30 sensor object
WiFiClient espClient;
PubSubClient client(espClient);

// Global variables
float currentTemp = 0.0;
float targetTemp = 25.0; // Default target temperature 25°C
bool deviceSwitch = false;

void setup() {
  Serial.begin(115200);
  pinMode(relayPin, OUTPUT);
  digitalWrite(relayPin, LOW); // Turn off relay initially

  // Initialize sensor
  if (!sht30.begin(0x44)) {
    Serial.println("Sensor initialization failed! Please check wiring");
    while (1);
  }

  // Connect to WiFi
  connectWiFi();

  // Connect to MQTT cloud server
  client.setServer(mqttBroker, mqttPort);
  client.setCallback(callback); // Set callback function for receiving cloud commands
  while (!client.connected()) {
    Serial.print("Connecting to MQTT...");
    if (client.connect("WiFiThermostat", mqttUsername, mqttPassword)) {
      Serial.println("Connected");
      client.subscribe("v1/devices/me/commands/#"); // Subscribe to control commands
    } else {
      Serial.print("Failed, state code=");
      Serial.print(client.state());
      Serial.println(" Retrying in 5 seconds");
      delay(5000);
    }
  }
}

void loop() {
  if (!client.connected()) {
    reconnect();
  }
  client.loop();

  // Read temperature data
  sensors_event_t humidity, temp;
  sht30.getEvent(&humidity, &temp);
  currentTemp = temp.temperature;
  Serial.print("Current temperature: ");
  Serial.println(currentTemp);

  // Upload temperature to cloud
  char tempMsg[20];
  dtostrf(currentTemp, 4, 2, tempMsg);
  client.publish("v1/devices/me/telemetry", "{\"temperature\":" + String(tempMsg) + "}");

  // Temperature control logic
  if (deviceSwitch) {
    if (currentTemp < targetTemp - 0.5) {
      digitalWrite(relayPin, HIGH); // Turn on heater
      Serial.println("Heater turned on");
    } else if (currentTemp > targetTemp + 0.5) {
      digitalWrite(relayPin, LOW); // Turn off heater
      Serial.println("Heater turned off");
    }
  } else {
    digitalWrite(relayPin, LOW); // Turn off heater when device is disabled
  }

  delay(2000); // Update data every 2 seconds
}

// WiFi connection function
void connectWiFi() {
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nWiFi connected");
  Serial.println("IP address: " + WiFi.localIP().toString());
}

// MQTT reconnection function
void reconnect() {
  while (!client.connected()) {
    if (client.connect("WiFiThermostat", mqttUsername, mqttPassword)) {
      Serial.println("MQTT reconnected");
      client.subscribe("v1/devices/me/commands/#");
    } else {
      Serial.print("MQTT reconnection failed, state code=");
      Serial.print(client.state());
      Serial.println(" Retrying in 5 seconds");
      delay(5000);
    }
  }
}

// Callback function (receive cloud commands)
void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Command received: ");
  String command = "";
  for (int i = 0; i < length; i++) {
    command += (char)payload[i];
  }
  Serial.println(command);

  // Parse command (example: {"target_temp":26.0, "device_switch":true})
  if (command.indexOf("target_temp") != -1) {
    targetTemp = parseValue(command, "target_temp");
    Serial.print("Target temperature updated to: ");
    Serial.println(targetTemp);
  }
  if (command.indexOf("device_switch") != -1) {
    deviceSwitch = (parseValue(command, "device_switch") == 1) ? true : false;
    Serial.print("Device switch: ");
    Serial.println(deviceSwitch ? "On" : "Off");
  }
}

// Helper function: Parse JSON value
float parseValue(String json, String key) {
  int keyIndex = json.indexOf(key) + key.length() + 2;
  int valueIndex = json.indexOf(",", keyIndex);
  if (valueIndex == -1) valueIndex = json.indexOf("}", keyIndex);
  String value = json.substring(keyIndex, valueIndex);
  return value.toFloat();
}