2023年7月9日 星期日

Remote control LED with ESP32 and MQTT

 Remote control LED with ESP32 and MQTT






Installing the PubSubClient Library

The PubSubClient library provides a client for doing simple publish/subscribe messaging with a server that supports MQTT (basically allows your ESP32 to talk with Node-RED).

  1. Click here to download the PubSubClient library. You should have a .zip folder in your Downloads folder
  2. Unzip the .zip folder and you should get pubsubclient-master folder
  3. Rename your folder from pubsubclient-master to pubsubclient
  4. Move the pubsubclient folder to your Arduino IDE installation libraries folder
  5. Then, re-open your Arduino IDE

The library comes with a number of example sketches. See File >Examples > PubSubClient within the Arduino IDE software.

Important: PubSubClient is not fully compatible with the ESP32, but the example provided in this tutorial is working very reliably during our tests.


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

// GPIO 2 D1
#define LED 2

// WiFi
const char *ssid = "alex9ufo"; // Enter your Wi-Fi name
const char *password = "alex9981";  // Enter Wi-Fi password

// MQTT Broker
const char *mqtt_broker = "broker.mqtt-dashboard.com";
const char *topic = "alex9ufo/esp32/led";
const char *mqtt_username = "alex9ufo";
const char *mqtt_password = "public";
const int mqtt_port = 1883;

bool ledState = false;

WiFiClient espClient;
PubSubClient client(espClient);
//===========================================================
void setup() {
    // Set software serial baud to 115200;
    Serial.begin(115200);
    delay(1000); // Delay for stability

    // Connecting to a WiFi network
    WiFi.begin(ssid, password);
    while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.println("Connecting to WiFi...");
    }
    Serial.println("Connected to the WiFi network");

    // Setting LED pin as output
    pinMode(LED, OUTPUT);
    digitalWrite(LED, LOW);  // Turn off the LED initially

    // Connecting to an MQTT broker
    client.setServer(mqtt_broker, mqtt_port);
    client.setCallback(callback);
    while (!client.connected()) {
        String client_id = "esp8266-client-";
        client_id += String(WiFi.macAddress());
        Serial.printf("The client %s connects to the public MQTT broker\n", client_id.c_str());
        if (client.connect(client_id.c_str(), mqtt_username, mqtt_password)) {
            Serial.println("Public HiveMQ MQTT broker connected");
        } else {
            Serial.print("Failed with state ");
            Serial.print(client.state());
            delay(2000);
        }
    }

    // Publish and subscribe
    client.publish(topic, "hello HiveMQ MQTT broker");
    client.subscribe(topic);
}
//===========================================================
void callback(char *topic, byte *payload, unsigned int length) {
    Serial.print("Message arrived in topic: ");
    Serial.println(topic);
    Serial.print("Message: ");
    String message;
    for (int i = 0; i < length; i++) {
        message += (char) payload[i];  // Convert *byte to string
    }
    Serial.print(message);
    if (message == "on" && !ledState) {
        digitalWrite(LED, HIGH);  // Turn on the LED
        ledState = true;
    }
    if (message == "off" && ledState) {
        digitalWrite(LED, LOW); // Turn off the LED
        ledState = false;
    }
    Serial.println();
    Serial.println("-----------------------");
}
//===========================================================
void loop() {
    client.loop();
    delay(100); // Delay for a short period in each loop iteration
}
//===========================================================

沒有留言:

張貼留言

113 學年度第 1 學期 RFID應用課程 Arduino程式

113 學年度第 1 學期 RFID應用課程 Arduino程式 https://www.mediafire.com/file/zr0h0p3iosq12jw/MFRC522+(2).7z/file 內含修改過後的 MFRC522 程式庫 (原程式有錯誤) //定義MFRC522...