Remote recording
Start and stop recording on a computer running Hand Tracker with Remote recording on (a camera rig on a Raspberry Pi, say), with a live preview of each camera.
Over Tailscale (from anywhere, with Tailscale on this device): its Tailscale name, such as pi or pi.your-tailnet.ts.net, or its 100.x address. No code is needed: only your own devices can reach it there.
On the same Wi-Fi without Tailscale: scan the QR code under Remote recording in Hand Tracker instead. It carries the code that page needs.
This opens the computer's own page (on port 47821) in the browser, since browsers don't let a website or app control a device on your network directly.