#include <WiFi.h>
#include <HTTPClient.h>
#include "DHT.h"
// WiFi credentials
const char* ssid = "Wokwi-GUEST";
const char* password = "";
// ThingSpeak
const String apiKey = "QCIMLNU3Z5QKUMZ3";
const String server = "http://api.thingspeak.com/update";
const int channelID = 3004763;
// DHT Sensor
#define DHTPIN 4
#define DHTTYPE DHT11
DHT dht(DHTPIN, DHTTYPE);
// Ultrasonic Sensor
#define TRIG_PIN 5
#define ECHO_PIN 18
// Gas Sensor (Analog)
#define GAS_SENSOR_PIN 34
// Digital LDR
#define LDR_PIN 14
// PIR Motion Sensor
#define PIR_PIN 27
void setup() {
 Serial.begin(115200);
 dht.begin();
 pinMode(TRIG_PIN, OUTPUT);
 pinMode(ECHO_PIN, INPUT);pinMode(LDR_PIN, INPUT);
 pinMode(PIR_PIN, INPUT);
 // Connect to WiFi
 WiFi.begin(ssid, password);
 Serial.print("Connecting to WiFi");
 while (WiFi.status() != WL_CONNECTED) {
 delay(500);
 Serial.print(".");
 }
 Serial.println("\nWiFi Connected");
}
void loop() {
 // Read DHT
 float temp = dht.readTemperature();
 float humidity = dht.readHumidity();
 // Ultrasonic distance
 digitalWrite(TRIG_PIN, LOW);
 delayMicroseconds(2);
 digitalWrite(TRIG_PIN, HIGH);
 delayMicroseconds(10);
 digitalWrite(TRIG_PIN, LOW);
 float duration = pulseIn(ECHO_PIN, HIGH);
 float distance = duration * 0.034 / 2;
 // Gas sensor reading
 int gasValue = analogRead(GAS_SENSOR_PIN);
 // LDR
 int ldrStatus = digitalRead(LDR_PIN);
 // PIR
 int motionDetected = digitalRead(PIR_PIN);
 // Log to serial
 Serial.println("Sending to ThingSpeak...");
 Serial.println("Temperature: " + String(temp));
 Serial.println("Humidity: " + String(humidity));Serial.println("Distance: " + String(distance));
 Serial.println("Gas: " + String(gasValue));
 Serial.println("LDR: " + String(ldrStatus));
 Serial.println("Motion: " + String(motionDetected));
 // Send data to ThingSpeak
 if (WiFi.status() == WL_CONNECTED) {
 HTTPClient http;
 String url = server + "?api_key=" + apiKey +
 "&field1=" + String(temp) +
 "&field2=" + String(humidity) +
 "&field3=" + String(distance) +
 "&field4=" + String(gasValue) +
 "&field5=" + String(ldrStatus) +
 "&field6=" + String(motionDetected);
 http.begin(url);
 int httpResponseCode = http.GET();
 Serial.println("Response: " + String(httpResponseCode));
 http.end();
 } else {
 Serial.println("WiFi Disconnected");
 }
 delay(15000); // 15 seconds delay as per ThingSpeak limit
}