Connecting Nintendo DS to Wi-Fi Without a Router: Use a Phone Hotspot

You cannot reliably turn a modern computer into an 802.11b/g access point for the Nintendo DS. The DS only supports 802.11b (11 Mbps) and WEP/WPA-PSK (TKIP)—standards most modern OS hotspot features don't support or expose.

Working Solutions

1. Smartphone Hotspot (Best): iOS/Android hotspots often support 2.4 GHz b/g/n and WPA2. The DS may connect if you set the hotspot to 2.4 GHz only and WPA-PSK (TKIP) (iOS: not configurable; Android: sometimes). Test it.
2. USB Wi-Fi Adapter + Virtual Router (Windows): Use a Realtek RTL8188EU/RTL8812BU dongle + Virtual Router Manager or netsh wlan set hostednetwork to create a b/g compatible AP. Hit-or-miss.
3. Dedicated Travel Router (Most Reliable): GL.iNet GL-AR300M or TP-Link TL-WR902AC ($25–35). Plug into hotel/office Ethernet or tether to phone via USB; broadcasts a DS-compatible 2.4 GHz WPA-TKIP network.