Introduction to ESP32 Blinking LED with WebSocket Control

This project demonstrates how to control an LED connected to an ESP32 using WebSocket communication. WebSocket provides full-duplex communication channels over a single TCP connection, making it ideal for real-time applications like controlling hardware devices remotely. In this case, the ESP32 will receive commands from a WebSocket client to toggle the LED's state.

Components Required

To build this project, you will need the following components: ESP32 development board, an LED, a 220Ω resistor, jumper wires, and a breadboard.

• Set up a WebSocket server on the ESP32 to listen for incoming connections from a WebSocket client.
• Connect the LED to a GPIO pin on the ESP32 through a 220Ω resistor.
• Write a simple WebSocket client (in HTML/JavaScript) to send messages (ON/OFF) to the ESP32.
• Control the LED's state on the ESP32 by toggling it based on the received WebSocket messages.
• Test the system by toggling the LED state using the WebSocket client.

Formula: LED State = (WebSocket Command) → ON/OFF

Components List

• 1 × ESP32 Development Board
• 1 × LED
• 1 × 220Ω Resistor
• Jumper wires
• Breadboard

Pin Configuration

• GPIO 5: The LED is connected to GPIO 5 of the ESP32 through a 220Ω resistor.

Ensure that the LED is connected to the correct GPIO pin and that the resistor is used to prevent overloading the ESP32 pin.

Wiring and Connections

• -> GPIO 5

Code for ESP32 Blinking LED with WebSocket Control

1#include <WiFi.h>
2#include <WebSocketsServer.h>
3
4const char* ssid = "Your_SSID";
5const char* password = "Your_PASSWORD";
6
7WebSocketsServer webSocket = WebSocketsServer(81);
8
9#define LED_PIN 5
10
11void setup() {
12  Serial.begin(115200);
13  pinMode(LED_PIN, OUTPUT);
14  WiFi.begin(ssid, password);
15  while (WiFi.status() != WL_CONNECTED) {
16    delay(1000);
17    Serial.println("Connecting to WiFi...");
18  }
19  Serial.println("Connected to WiFi");
20  webSocket.begin();
21  webSocket.onEvent(webSocketEvent);
22}
23
24void loop() {
25  webSocket.loop();
26}
27
28void webSocketEvent(uint8_t num, WStype_t type, uint8_t * payload, size_t length) {
29  if (type == WStype_TEXT) {
30    String message = (char*) payload;
31    if (message == "ON") {
32      digitalWrite(LED_PIN, HIGH);
33    } else if (message == "OFF") {
34      digitalWrite(LED_PIN, LOW);
35    }
36  }
37}

Code Explanation

• #include <WiFi.h>: This includes the necessary WiFi library to connect the ESP32 to a Wi-Fi network.
• #include <WebSocketsServer.h>: This includes the WebSockets library, which allows the ESP32 to act as a WebSocket server.
• const char* ssid = "Your_SSID";: This defines the Wi-Fi SSID for the ESP32 to connect to.
• const char* password = "Your_PASSWORD";: This defines the Wi-Fi password for the ESP32 to connect to.
• WebSocketsServer webSocket = WebSocketsServer(81);: This initializes the WebSocket server on port 81.
• pinMode(LED_PIN, OUTPUT);: This sets GPIO 5 (connected to the LED) as an output.
• WiFi.begin(ssid, password);: This starts the Wi-Fi connection process on the ESP32.
• webSocket.begin();: This begins the WebSocket server, allowing it to accept incoming WebSocket connections.
• webSocket.onEvent(webSocketEvent);: This registers the WebSocket event handler function to manage incoming messages.
• webSocket.loop();: This keeps the WebSocket server active, processing messages from clients.
• String message = (char*) payload;: This converts the incoming WebSocket payload into a string.
• if (message == "ON") { digitalWrite(LED_PIN, HIGH); }: If the WebSocket message is 'ON', the LED is turned on (HIGH).
• else if (message == "OFF") { digitalWrite(LED_PIN, LOW); }: If the WebSocket message is 'OFF', the LED is turned off (LOW).

Applications

• Real-time control systems.
• Home automation and IoT devices.
• Remote monitoring and control of physical devices.

Conclusion

The ESP32 Blinking LED with WebSocket Control project demonstrates how to use WebSocket communication to control an LED in real-time. This is a foundational project that can be extended to control various devices, sensors, and actuators remotely through WebSocket.