D1 Mini Relay Shield

/*
To control a D1 Mini Relay Shield through a web server, you can use the following code example. This code is written for the ESP8266-based D1 Mini board using the Arduino IDE. Make sure to install the "ESP8266WiFi" library before compiling and uploading the code to the board.

This code sets up a simple web server that serves an HTML page with a button to toggle the relay. The button sends a request to the "/toggle" route, which toggles the relay state and redirects the user back to the main page.
*/

#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <ESP8266WebServer.h>

// Replace with your network credentials
const char* ssid = "your_SSID";
const char* password = "your_PASSWORD";

// Create an instance of the server
ESP8266WebServer server(80);

// Relay control pin
const int relayPin = D1;
bool relayState = false;

void setup() {
  Serial.begin(115200);
  pinMode(relayPin, OUTPUT);
  digitalWrite(relayPin, relayState);

  // Connect to Wi-Fi
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to Wi-Fi...");
  }
  Serial.println("Connected to Wi-Fi");

  // Setup web server routes
  server.on("/", handleRoot);
  server.on("/toggle", handleToggle);
  server.begin();
  Serial.println("Web server started");
}

void loop() {
  server.handleClient();
}

void handleRoot() {
  String html = "<html><body><h1>D1 Mini Relay Control</h1>";
  html += "<p><a href=\"/toggle\"><button>Toggle Relay</button></a></p>";
  html += "</body></html>";
  server.send(200, "text/html", html);
}

void handleToggle() {
  relayState = !relayState;
  digitalWrite(relayPin, relayState);
  String message = relayState ? "Relay ON" : "Relay OFF";
  Serial.println(message);
  server.sendHeader("Location", "/");
  server.send(303);
}