ufoex/azahar-viewer

Azahar Viewer is an Android app that turns a second phone into a working touch screen for a Nintendo 3DS emulator. The 3DS is a handheld game console with two screens: a top display and a smaller bottom touch screen. When you run a 3DS game on an emulator on one phone, this app lets you use a separate phone as that bottom screen. It receives a live video feed of the bottom screen over your local Wi-Fi and sends your touch input back to the emulator. The result is that the second phone acts like a real second touchscreen, not just a passive display. The app automatically finds emulators on your network that are streaming, so you never have to type in IP addresses. It decodes the video using the phone's hardware decoder, which keeps battery and processor usage low, and displays it at the correct 4:3 aspect ratio. Touch events you make on the second phone are sent back to the emulator over the same connection, letting you interact with menus, keyboards, and drawing games. The app also shows a reconnect prompt if the stream drops, rather than failing quietly. It supports English and Spanish, matching your device's system language. To use it, you install this app on the phone that will serve as the second screen. On the phone running the modified emulator, you start a game, open the in-game menu, and choose the option to stream the bottom screen. Then you open this app, pick the emulator from the automatically generated list, and start touching the screen. The project is written entirely in Kotlin and works on Android 5.0 and above. The creator describes it as a personal proof of concept. It supports one client at a time, has no encryption or authentication on the stream, and is intended for home use on a trusted network. Anyone on the same local network could in principle connect to the stream, so it is not built for environments beyond a private Wi-Fi setup.