บทความ: ESP32 + Node-RED + Dashboard 2.0 + Home Assistant คู่มือสมบูรณ์ 2026

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

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

// ===== MQTT Configuration =====
const char* mqtt_server = "192.168.1.100";  // IP ของ MQTT Broker (Raspberry Pi)
const int mqtt_port = 1883;
const char* mqtt_user = "homeassistant";    // ถ้ามี
const char* mqtt_password = "your_password"; // ถ้ามี

// ===== Sensor Configuration =====
#define DHTPIN 4
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);

// ===== Topics =====
const char* temp_topic = "home/sensor/temperature";
const char* hum_topic = "home/sensor/humidity";

// ===== Objects =====
WiFiClient espClient;
PubSubClient client(espClient);

// ===== ตัวแปร =====
unsigned long lastMsg = 0;
const long interval = 5000;  // ส่งข้อมูลทุก 5 วินาที

void setup() {
  Serial.begin(115200);
  dht.begin();

  // เชื่อมต่อ WiFi
  setup_wifi();

  // ตั้งค่า MQTT
  client.setServer(mqtt_server, mqtt_port);
  client.setCallback(callback);
}

void setup_wifi() {
  delay(10);
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}

// ===== Callback: รับคำสั่งจาก MQTT =====
void callback(char* topic, byte* message, unsigned int length) {
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("]: ");

  String messageTemp;

  for (int i = 0; i < length; i++) {
    messageTemp += (char)message[i];
  }
  Serial.println(messageTemp);

  // ตัวอย่าง: ควบคุม Relay ถ้าได้รับคำสั่ง
  if (String(topic) == "home/relay/command") {
    if (messageTemp == "ON") {
      digitalWrite(RELAY_PIN, HIGH);
      Serial.println("Relay turned ON");
    } else if (messageTemp == "OFF") {
      digitalWrite(RELAY_PIN, LOW);
      Serial.println("Relay turned OFF");
    }
  }
}

void reconnect() {
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    
    // สร้าง Client ID แบบสุ่ม
    String clientId = "ESP32Client-";
    clientId += String(random(0xffff), HEX);

    if (client.connect(clientId.c_str(), mqtt_user, mqtt_password)) {
      Serial.println("connected");
      
      // Subscribe หัวข้อที่ต้องการรับคำสั่ง
      client.subscribe("home/relay/command");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" retrying in 5 seconds");
      delay(5000);
    }
  }
}

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

  // ===== ส่งข้อมูล Sensor ทุก 5 วินาที =====
  unsigned long now = millis();
  if (now - lastMsg > interval) {
    lastMsg = now;

    // อ่านค่าอุณหภูมิและความชื้น
    float temp = dht.readTemperature();
    float hum = dht.readHumidity();

    // ตรวจสอบว่าอ่านค่าได้หรือไม่
    if (isnan(temp) || isnan(hum)) {
      Serial.println("Failed to read from DHT sensor!");
      return;
    }

    // แปลงค่าเป็น String
    char tempStr[8];
    char humStr[8];
    dtostrf(temp, 1, 2, tempStr);
    dtostrf(hum, 1, 2, humStr);

    // ส่งข้อมูลผ่าน MQTT
    client.publish(temp_topic, tempStr);
    client.publish(hum_topic, humStr);

    Serial.print("Temperature: ");
    Serial.print(temp);
    Serial.print("°C | Humidity: ");
    Serial.print(hum);
    Serial.println("%");
  }
}

# อัปเดตระบบ
sudo apt update && sudo apt upgrade -y

# ติดตั้ง Node.js (เวอร์ชัน LTS)
curl -fsSL https://deb.nodesource.com/setup_lts.x | sudo -E bash -
sudo apt install -y nodejs

# ติดตั้ง Node-RED
sudo npm install -g --unsafe-perm node-red

# ติดตั้ง Dashboard 2.0
cd ~/.node-red
npm install @node-red/dashboard

# เริ่ม Node-RED
node-red

[
    {
        "id": "mqtt-in-temp",
        "type": "mqtt in",
        "z": "d89c6f8.b23859",
        "name": "",
        "topic": "home/sensor/temperature",
        "qos": "0",
        "datatype": "auto",
        "broker": "mqtt-broker",
        "nl": false,
        "rap": true,
        "rh": 0,
        "inputs": 0,
        "x": 140,
        "y": 100,
        "wires": [["chart-temp", "gauge-temp"]]
    },
    {
        "id": "chart-temp",
        "type": "ui-chart",
        "z": "d89c6f8.b23859",
        "name": "Temperature",
        "group": "sensors-group",
        "order": 1,
        "width": "12",
        "height": "6",
        "label": "อุณหภูมิ (°C)",
        "chartType": "line",
        "legend": "false",
        "xformat": "HH:mm:ss",
        "interpolate": true,
        "nodata": "",
        "dot": true,
        "ymin": "",
        "ymax": "",
        "removeOlder": "1",
        "removeOlderUnit": "3600",
        "cutout": 0,
        "useOneColor": false,
        "colors": ["#1f77b4", "#aec7e8", "#ff7f0e", "#2ca02c", "#98df8a", "#d62728", "#ff9896", "#9467bd", "#c5b0d5"],
        "useOldStyle": false,
        "outputs": 1,
        "x": 450,
        "y": 100,
        "wires": [[]]
    },
    {
        "id": "gauge-temp",
        "type": "ui-gauge",
        "z": "d89c6f8.b23859",
        "name": "",
        "group": "sensors-group",
        "order": 2,
        "width": "6",
        "height": "4",
        "name": "",
        "label": "อุณหภูมิ",
        "format": "°C",
        "min": "0",
        "max": "50",
        "colors": ["#00b500", "#e6e600", "#ca3838"],
        "seg1": "",
        "seg2": "",
        "diff": false,
        "className": "",
        "x": 450,
        "y": 180,
        "wires": [[]]
    },
    {
        "id": "mqtt-broker",
        "type": "mqtt-broker",
        "name": "Local MQTT",
        "broker": "192.168.1.100",
        "port": "1883",
        "clientid": "",
        "autoConnect": true,
        "usetls": false,
        "protocolVersion": "4",
        "keepalive": "60",
        "cleansession": true,
        "birthTopic": "",
        "birthQos": "0",
        "birthPayload": "",
        "birthMsg": {},
        "closeTopic": "",
        "closeQos": "0",
        "closePayload": "",
        "closeMsg": {},
        "willTopic": "",
        "willQos": "0",
        "willPayload": "",
        "willMsg": {},
        "sessionExpiry": ""
    },
    {
        "id": "sensors-group",
        "type": "ui-group",
        "name": "Sensors",
        "page": "",
        "width": "12",
        "height": "1",
        "order": 1
    }
]

# configuration.yaml

# MQTT Sensor สำหรับอุณหภูมิ
mqtt:
  sensor:
    - name: "ESP32 Temperature"
      state_topic: "home/sensor/temperature"
      unit_of_measurement: "°C"
      device_class: temperature
      
    - name: "ESP32 Humidity"
      state_topic: "home/sensor/humidity"
      unit_of_measurement: "%"
      device_class: humidity

// ใน Function Node ของ Node-RED
msg.headers = {
    "Content-Type": "application/json",
    "Authorization": "Bearer YOUR_LONG_LIVED_ACCESS_TOKEN"
};

msg.payload = {
    "state": msg.payload,
    "attributes": {
        "unit_of_measurement": "°C",
        "friendly_name": "ESP32 Temperature"
    }
};

return msg;

// แล้วต่อกับ HTTP Request Node ไปที่:
// POST http://<HOME_ASSISTANT_IP>:8123/api/states/sensor.esp32_temperature