Sebastiaan de With of Lux Entertainment and Optics Incorporated writes:
Orion is a small, fun app that helps you use your iPad as an external HDMI display for any camera, video game console, or even VHS. Just plug in one of the bajillion inexpensive adapters, and Orion handles the rest.
What a lovely—and amusingly retro—hack! You could use Orion as an external monitor to preview camera video and still output, extend the desktop of any Mac or PC, or play with old consumer electronic devices with HDMI output.
It requires an iPad with USB-C, iPadOS 17, and a USB-C to HDMI “capture card.” Lux recommends a particular $14.99 dongle and maintains a compatibility document listing others that work and don’t work (including some from well-known names).
Orion is free, but if you want to support the app, there’s a one-time $5 upgrade to Orion Pro that offers AI upscaling, CRT emulation for retro games, and image adjustments, plus any future features the developers feel like adding.