DHT11 + ThingSpeak (NodeMCU)

// DHT11 Temperature & Humidity to ThingSpeak
// Install: DHT sensor library, ThingSpeak library

#include <ESP8266WiFi.h>
#include <DHT.h>
#include <ThingSpeak.h>

#define DHTPIN D7      // DHT11 data pin (GPIO13)
#define DHTTYPE DHT11

// WiFi credentials
const char* ssid = \"YOUR_WIFI_SSID\";
const char* password = \"YOUR_WIFI_PASSWORD\";

// ThingSpeak credentials
unsigned long channelID = 1234567;        // Your channel ID
const char* writeAPIKey = \"YOUR_API_KEY\";

DHT dht(DHTPIN, DHTTYPE);
WiFiClient client;

void setup() {
  Serial.begin(9600);
  dht.begin();

  Serial.println(\"Connecting to WiFi...\");
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(\".\");
  }
  Serial.println(\"\");
  Serial.println(\"WiFi connected\");

  ThingSpeak.begin(client);
}

void loop() {
  float humidity = dht.readHumidity();
  float temperature = dht.readTemperature();

  if (isnan(humidity) || isnan(temperature)) {
    Serial.println(\"Failed to read DHT11!\");
    delay(2000);
    return;
  }

  Serial.print(\"Temp: \");
  Serial.print(temperature);
  Serial.print(\" C, Humidity: \");
  Serial.println(humidity);

  ThingSpeak.setField(1, temperature);
  ThingSpeak.setField(2, humidity);
  int status = ThingSpeak.writeFields(channelID, writeAPIKey);

  if (status == 200) {
    Serial.println(\"Data sent to ThingSpeak\");
  } else {
    Serial.print(\"ThingSpeak error: \");
    Serial.println(status);
  }

  delay(20000);  // ThingSpeak allows 1 update per 15 seconds
}