ESP32: How to use Wi-Fi Scan, Select, and Connect Interactive Terminal

				
					#include <WiFi.h>

// Variables for user input
String inputSSID = "SSID";
String inputPassword = "PASSWORD";

// Timeouts for user input
const long INPUT_TIMEOUT = 30000; // 30 seconds
void scanNetworks() {
  Serial.println("\n--- Scanning for Wi-Fi Networks ---");
 
  // Wi-Fi.scanNetworks returns the number of networks found
  int n = WiFi.scanNetworks();
 
  if (n == 0) {
    Serial.println("No networks found.");
  } else {
    Serial.print(n);
    Serial.println(" networks found:");
    for (int i = 0; i < n; ++i) {
      // Print network details
      Serial.print(i + 1);
      Serial.print(": ");
      Serial.print(WiFi.SSID(i));
      Serial.print(" (Signal: ");
      Serial.print(WiFi.RSSI(i)); // Received Signal Strength Indicator
      Serial.print(" dBm, Enc: ");
      // Check for security type (not detailed here, but good for context)
      if (WiFi.encryptionType(i) == WIFI_AUTH_OPEN) {
        Serial.println("Open)");
      } else {
        Serial.println("Secured)");
      }
      delay(10);
    }
  }
  Serial.println("-----------------------------------");
  // Clean up the scan results
  WiFi.scanDelete();
}

bool getCredentialsFromUser() {
 
  // --- Get SSID ---
  Serial.println("\nPlease enter the desired SSID and press Enter (30s timeout):");
  // Set the timeout for reading the string
  long startTime = millis();
  while (millis() - startTime < INPUT_TIMEOUT) {
    if (Serial.available()) {
      // Read the string until a newline ('\n') character
      inputSSID = Serial.readStringUntil('\n');
      inputSSID.trim(); // Remove any leading/trailing whitespace
      if (inputSSID.length() > 0) {
        break;
      }
    }
    delay(100);
  }

  if (inputSSID.length() == 0) {
    Serial.println("SSID input timed out.");
    return false;
  }
 
  // --- Get Password ---
  Serial.println("SSID received. Now enter the password and press Enter (30s timeout):");
  startTime = millis();
  while (millis() - startTime < INPUT_TIMEOUT) {
    if (Serial.available()) {
      // Read the string until a newline ('\n') character
      inputPassword = Serial.readStringUntil('\n');
      inputPassword.trim(); // Remove any leading/trailing whitespace
      // Note: We allow empty password for open networks
      break;
    }
    delay(100);
  }
 
  Serial.print("\nAttempting to connect to SSID: ");
  Serial.println(inputSSID);
  return true;
}

void attemptConnection() {
  // Disconnect any previous connection
  WiFi.disconnect();
 
  // Set ESP32 to Wi-Fi Station mode
  WiFi.mode(WIFI_STA);
 
  // Begin connection attempt
  WiFi.begin(inputSSID.c_str(), inputPassword.c_str());

  int attempts = 0;
  // Wait for connection, up to 20 attempts (20 seconds)
  while (WiFi.status() != WL_CONNECTED && attempts < 20) {
    delay(1000);
    Serial.print(".");
    attempts++;
  }

  // Check final status
  if (WiFi.status() == WL_CONNECTED) {
    Serial.println("\nSUCCESS! ESP32 Connected.");
    Serial.print("IP Address: ");
    Serial.println(WiFi.localIP());
  } else {
    Serial.println("\nCONNECTION FAILED after 20 attempts.");
    Serial.println("Please reset the board to try again.");
  }
}

void setup() {
  Serial.begin(115200);
  delay(1000);

  // 1. Scan for networks and display the list
  scanNetworks();

  // 2. Get credentials from the user via the Serial Monitor
  if (getCredentialsFromUser()) {
    // 3. Attempt to connect using the received credentials
    attemptConnection();
  } else {
    Serial.println("Failed to get valid credentials. Program halting.");
  }
}

void loop() {
  // Nothing needs to run constantly in the loop for this demo
}