Wokwi - Online ESP32, STM32, Arduino Simulator

#include <WiFi.h>
#include <WebServer.h>

// Replace with your Wi-Fi credentials
const char* ssid = "YOUR_SSID";
const char* password = "YOUR_PASSWORD";

WebServer server(80);

void setup() {
  Serial.begin(115200);
  // Connect to Wi-Fi
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.println("Connecting to WiFi...");
  }
  Serial.println("Connected to Wi-Fi.");

  // Start the server
  server.on("/", handleRoot);
  server.begin();
  Serial.println("HTTP server started.");
  
  // Initialize pin 21 as an analog input
  analogReadResolution(12); // 12-bit resolution for ESP32
}

void loop() {
  // Handle client requests
  server.handleClient();
}

void handleRoot() {
  int readValue = analogRead(21); // Read the analog value from pin 21
  float voltage = readValue * (3.3 / 4095.0); // Convert to voltage
  
  String html = "<!DOCTYPE html><html><head><meta http-equiv='refresh' content='1'/><title>Voltage Reader</title></head><body><h1>Voltage on Pin 21: " + String(voltage) + " V</h1></body></html>";
  
  server.send(200, "text/html", html);
}
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esp32-s2-devkitm-1