Wi-Fi Connection Manager

Why a connection manager

Hard-coding an SSID and password works on your bench and nowhere else. The moment the board moves — a new classroom, a customer's home, a different router — it goes dark. A connection manager fixes this: the board stores known credentials, reconnects automatically, and falls back to its own access point so you can hand it new credentials from a phone.

The three states

A reliable manager only ever sits in one of three states:

• Connected — joined a known network, running the application.
• Connecting — trying saved credentials, with a timeout.
• Provisioning — no network reachable, so the board hosts a captive portal AP named LB-Setup for the user to pick a network and enter a password.

Minimal sketch

This skeleton connects with a timeout, then drops into AP mode if it fails:

#include <WiFi.h>
#include <Preferences.h>

Preferences prefs;

bool connectSaved(uint32_t timeoutMs) {
  prefs.begin("wifi", true);
  String ssid = prefs.getString("ssid", "");
  String pass = prefs.getString("pass", "");
  prefs.end();
  if (ssid.isEmpty()) return false;

  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid.c_str(), pass.c_str());

  uint32_t start = millis();
  while (WiFi.status() != WL_CONNECTED) {
    if (millis() - start > timeoutMs) return false;
    delay(200);
  }
  return true;
}

void startPortal() {
  WiFi.mode(WIFI_AP);
  WiFi.softAP("LB-Setup");
  // serve a form on 192.168.4.1, write submitted creds to prefs
}

void setup() {
  Serial.begin(115200);
  if (!connectSaved(8000)) startPortal();
}

void loop() {}

Where to go next

Pair this with mDNS so the board is reachable at lb-board.local, and add an OTA endpoint so you never need the USB cable again.