Hi all, author here.
On macOS (Mojave, Catalina, ...) you can lock/unlock the computer with an Apple Watch by proximity. But I don't want an Apple Watch...
So I made a program to replicate this feature. It connects to any (classic) Bluetooth device and keeps monitoring the intensity of their Bluetooth signal (rssi). When it is below a threshold (defined by the user) it locks the computer. When it is above it unlocks.
Unlike Apple's version, my program doesn't require WiFi and works even with older Macs that don't support Auto Unlock. However it doesn't handle admin login or does 2-factor authentication, yet. That might come later.
I posted here before a Windows version[0], but it only works with Android phones.