실습 2 : 온습도값 AWS mqtt & Node-RED 출력

실습 순서

1. Node-RED 접속:
브라우저에서 http://localhost:1880 로 접속.


2. 노드 추가:
노드 구성



3. MQTT Out 노드 설정:
- topic을 esp32/pub으로 바꿈.


4. function 노드 설정:
- humidity



    msg.payload = msg.payload.humidity;
    return msg;


- temperature



    msg.payload = msg.payload.temperature;
    return msg;




5. 결과 확인

- Serial Monitor


- node-red debug


- node-red dashboard

코드

                            
    #include "secrets.h"
    #include ≶WiFiClientSecure.h>
    #include ≶MQTTClient.h>
    #include ≶ArduinoJson.h>
    #include ≶DHT.h>
    #include ≶WiFi.h>
    
    // AWS IoT 설정
    #define AWS_IOT_PUBLISH_TOPIC   "esp32/pub"
    #define AWS_IOT_SUBSCRIBE_TOPIC "esp32/sub"
    
    // DHT11 센서 설정
    #define DHT_PIN 13       // DHT11 데이터 핀
    #define DHT_TYPE DHT11  // DHT11 센서
    
    WiFiClientSecure net;
    MQTTClient client;
    
    DHT dht(DHT_PIN, DHT_TYPE);
    
    void connectAWS()
    {
        WiFi.mode(WIFI_STA);
        WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
    
        Serial.println("Connecting to Wi-Fi");
    
        while (WiFi.status() != WL_CONNECTED){
        delay(500);
        Serial.print(".");
        }
    
        // Configure WiFiClientSecure to use the AWS IoT device credentials
        net.setCACert(AWS_CERT_CA);
        net.setCertificate(AWS_CERT_CRT);
        net.setPrivateKey(AWS_CERT_PRIVATE);
    
        // Connect to the MQTT broker on the AWS endpoint we defined earlier
        client.begin(AWS_IOT_ENDPOINT, 8883, net);
    
        // Create a message handler
        client.onMessage(messageHandler);
    
        Serial.print("Connecting to AWS IoT");
    
        while (!client.connect(THINGNAME)) {
        Serial.print(".");
        delay(100);
        }
    
        if(!client.connected()){
        Serial.println("AWS IoT Timeout!");
        return;
        }
    
        // Subscribe to a topic
        client.subscribe(AWS_IOT_SUBSCRIBE_TOPIC);
    
        Serial.println("AWS IoT Connected!");
    }
    
    void publishMessage(float temperature, float humidity)
    {
        StaticJsonDocument≶200> doc;
        doc["temperature"] = temperature;
        doc["humidity"] = humidity;
        char jsonBuffer[512];
        serializeJson(doc, jsonBuffer);
    
        client.publish(AWS_IOT_PUBLISH_TOPIC, jsonBuffer);
    }
    
    void messageHandler(String &topic, String &payload) {
        Serial.println("incoming: " + topic + " - " + payload);
    }
    
    void setup() {
        Serial.begin(9600);
        connectAWS();
        dht.begin();
    }
    
    void loop() {
        // 온습도 데이터 읽기
        float temperature = dht.readTemperature();
        float humidity = dht.readHumidity();
        Serial.println(temperature);
        Serial.println(humidity);
    
        // 온습도 데이터를 Node-RED로 전송
        // JSON 형식으로 데이터를 생성하여 MQTT 메시지로 전송
        StaticJsonDocument≶200> doc;
        doc["temperature"] = temperature;
        doc["humidity"] = humidity;
        char jsonBuffer[512];
        serializeJson(doc, jsonBuffer);
        client.publish("node-red/esp32-data", jsonBuffer); // Node-RED에서 subscribe할 토픽을 "node-red/esp32-data"로 지정
    
        // AWS IoT에도 데이터를 전송
        publishMessage(temperature, humidity);
    
        // AWS IoT 클라이언트 루프
        client.loop();
    
        delay(1000);
    }