Picture this: you brought your shiny new gaming laptop to Starbucks to play a few rounds of Fortnite, but someone walks up, grabs your PC, and takes off. Your laptop was unlocked, so now they could potentially access your passwords, private messages, and other personal information. Michael Altfield presents an interesting solution on his personal blog: the "BusKill."
Altfield built the BusKill for around $20, using a cheap USB drive (which is kept on your person), a keyring, a magnetic USB breakaway adapter, and a 1-meter USB extension cable. He then used udev, a Linux application for managing connected devices, to lock the screen whenever the USB drive is removed. The end result is a laptop that locks itself whenever the magnetic link to the owner is severed.
This specific solution relies on using Linux-based software, but it would be possible to adapt the BusKill to work on Windows and other operating systems with a bit more work.
While the intended audience for this is anyone working on extremely-sensitive information in public, it's still an interesting hardware project that doesn't take a lot of time (or money) to replicate. No soldering iron required for this one, folks.
You can check out the full tutorial on Michael Altfield's blog.