Optimize WiFi connection time by using WIFI_FAST_SCAN

[m-RNA]

Summary

Optimizes WiFi connection startup time in wifiManager.cpp by switching from full channel scan to fast scan mode.

Before: WiFi connected at ~6279ms
After: WiFi connected at ~3897ms
Improvement: ~2000ms faster

Changes

File: wifiManager.cpp

1. Switch to WIFI_FAST_SCAN mode

// Changed from WIFI_ALL_CHANNEL_SCAN to WIFI_FAST_SCAN
_wifi_cfg.sta.scan_method = WIFI_FAST_SCAN;

Why WIFI_FAST_SCAN is faster:

Mode	Behavior	Time
WIFI_ALL_CHANNEL_SCAN	Scans all 14 channels (~100ms each), collects all matching APs, then selects the best one	~1.5-3s
WIFI_FAST_SCAN	Stops scanning immediately when first matching AP is found	~100-500ms

Trade-off: May not connect to the strongest AP if multiple APs share the same SSID. This is acceptable for typical single-AP home/lab environments where this eye tracker operates.

2.Check whether WIFI is open before closing

wifi_mode_t mode;
if (esp_wifi_get_mode(&mode) == ESP_OK) {
  esp_wifi_stop();
}

First connection - WiFi hasn't started yet. Check whether WIFI is open before closing

3. Reduce connection timeout

Changed portMAX_DELAY to pdMS_TO_TICKS(8000) for hardcoded credentials connection. This doesn't affect successful connection time but prevents indefinite blocking on failures.

Testing

• Tested with WPA2-PSK network
• Device: wrooms3QIO
• CONFIG_GENERAL_ENABLE_WIRELESS=y
• Mode: WiFi