#include <WiFi.h>
#include <PubSubClient.h>
#include <DHT.h>
const char* ssid = "Wokwi-GUEST";
const char* pwd = "";
const char* broker = "broker.hivemq.com";
const char* t_led = "IOT-G9/led";
const char* t_temp = "IOT-G9/temp";
const char* t_hum = "IOT-G9/hum";
const int dhtPin = 4;
const int ledPin = 2;
DHT dht(dhtPin, DHT22);
WiFiClient espClient;
PubSubClient client(espClient);
unsigned long lastMsg = 0;
void callback(char* t, byte* payload, unsigned int len) {
String msg = String((char*)payload, len);
if (msg == "on") digitalWrite(ledPin, HIGH);
if (msg == "off") digitalWrite(ledPin, LOW);
}
void setup() {
pinMode(ledPin, OUTPUT);
dht.begin();
WiFi.begin(ssid, pwd);
while (WiFi.status() != WL_CONNECTED) delay(50);
client.setServer(broker, 1883);
client.setCallback(callback);
}
void loop() {
if (!client.connected()) {
if (client.connect("ESP32_Wokwi")) {
client.subscribe(t_led);
}
delay(500);
} else {
client.loop();
unsigned long now = millis();
if (now - lastMsg > 5000) {
lastMsg = now;
client.publish(t_temp, String(dht.readTemperature()).c_str());
client.publish(t_hum, String(dht.readHumidity()).c_str());
}
}
}