Published: Wed, Jul 02, 25

Building a Simple CLI Menu with Wi-Fi Scanning

Description

This project demonstrates how to build a basic serial CLI (Command Line Interface) menu on the ESP32-C3 using the Arduino IDE. Instead of endlessly looping code, this approach waits for user input over serial to trigger specific actions—in this case, scanning for nearby Wi-Fi networks.

Full Source Code:

#include "WiFi.h"

// Flag to indicate whether we should scan Wi-Fi
bool wifiScan = false;

void showMenu() {
  Serial.println(F(" _________________________"));
  Serial.println(F("|     ESP32-C3 Super     |"));
  Serial.println(F("|      Mini Board        |"));
  Serial.println(F("|------------------------|"));
  Serial.println(F("| [ ] EN           IO10  |"));  
  Serial.println(F("| [ ] 3V3          IO6   |"));
  Serial.println(F("| [ ] IO0          IO7   |"));
  Serial.println(F("| [ ] GND          IO5   |"));
  Serial.println(F("| [ ] IO1          IO4   |"));
  Serial.println(F("| [ ] IO2          IO3   |"));
  Serial.println(F("| [ ] IO8          GND   |"));
  Serial.println(F("| [ ] IO9          5V    |"));
  Serial.println(F("|------------------------|"));
  Serial.println(F("|__USB-C________RST BTN__|"));
  Serial.println(F("")); 
  Serial.println(F("  [s]  Wi-Fi scan      "));
  Serial.println(F("  [m]  Show menu again "));
}

void handleMenuInput(char input) {
  switch (input) {
    case 's':
      wifiScan = true;
      break;
    case 'm':
      showMenu();
      break;
    default:
      Serial.println(F("? Unknown command. Type 'm' to show menu options."));
      break;
  }
}

void scanWifi() {
  Serial.println("\nStarting Wi-Fi Scan...");

  int n = WiFi.scanNetworks();
  Serial.println("Scan complete.");

  if (n == 0) {
    Serial.println("No networks found.");
  } else {
    Serial.printf("%d networks found:\n", n);
    Serial.println("Nr | SSID                             | RSSI | CH | Encryption");

    for (int i = 0; i < n; ++i) {
      Serial.printf("%2d | %-32.32s | %4d | %2d | ",
                    i + 1,
                    WiFi.SSID(i).c_str(),
                    WiFi.RSSI(i),
                    WiFi.channel(i));

      switch (WiFi.encryptionType(i)) {
        case WIFI_AUTH_OPEN:           Serial.print("Open"); break;
        case WIFI_AUTH_WEP:            Serial.print("WEP"); break;
        case WIFI_AUTH_WPA_PSK:        Serial.print("WPA"); break;
        case WIFI_AUTH_WPA2_PSK:       Serial.print("WPA2"); break;
        case WIFI_AUTH_WPA_WPA2_PSK:   Serial.print("WPA+WPA2"); break;
        case WIFI_AUTH_WPA2_ENTERPRISE:Serial.print("WPA2-EAP"); break;
        case WIFI_AUTH_WPA3_PSK:       Serial.print("WPA3"); break;
        case WIFI_AUTH_WPA2_WPA3_PSK:  Serial.print("WPA2+WPA3"); break;
        case WIFI_AUTH_WAPI_PSK:       Serial.print("WAPI"); break;
        default:                       Serial.print("Unknown"); break;
      }

      Serial.println();
      delay(10);
    }
  }

  WiFi.scanDelete(); // free memory from scan result

  wifiScan = false; // reset flag
}

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

  // Set Wi-Fi to station mode and disconnect from any previous connection
  WiFi.mode(WIFI_STA);
  WiFi.disconnect();
  delay(100);

  Serial.println("WiFi Scanner Ready.");
  showMenu();
}

void loop() {
  if (Serial.available()) {
    char input = Serial.read();

    // Ignore newlines/carriage returns
    if (input != '\n' && input != '\r') {
      handleMenuInput(input);
    }

    // Clear the rest of the buffer
    while (Serial.available()) {
      Serial.read();
    }
  }

  if (wifiScan) {
    scanWifi();
  }
}

Example Output:

Starting Wi-Fi Scan...
Scan complete.
12 networks found:
Nr | SSID                             | RSSI | CH | Encryption
 1 | TL;DR                            |  -37 | 11 | WPA2+WPA3
 2 | North Korea's Wi-Fi              |  -45 | 11 | WPA2

The code provides:

✅ A serial menu printed at startup

✅ User commands:

[s] → Start Wi-Fi scan

[m] → Show menu again

✅ A nicely formatted Wi-Fi scan result with:

SSID

RSSI (signal strength)

Channel

Encryption type

This is a great template for adding more CLI commands for future ESP32-C3 projects.

 _________________________
|     ESP32-C3 Super     |
|      Mini Board        |
|------------------------|
| [ ] EN           IO10  |
| [ ] 3V3          IO6   |
| [ ] IO0          IO7   |
| [ ] GND          IO5   |
| [ ] IO1          IO4   |
| [ ] IO2          IO3   |
| [ ] IO8          GND   |
| [ ] IO9          5V    |
|------------------------|
|__USB-C________RST BTN__|

  [s]  Wi-Fi scan
  [m]  Show menu again

Press s → Performs a Wi-Fi scan.

Press m → Displays the menu again.

Benefits of CLI Over Endless Loops

Instead of having the sketch run a single task in loop() forever, a CLI lets you:

Interactively choose features to test or run

Avoid cluttering serial output with constant scanning or logging

Build modular code, where each feature is wrapped into its own function

Ideas to Extend This Sketch

Add Bluetooth scanning

Control GPIO pins via commands

Display system information (chip ID, heap size, etc.)

Change the board’s name via serial command

Save settings to NVS or EEPROM