How anti-theft tags work - magnetostriction on HackerTube: recommended by 1 Hacker News commenter across 1 month, 2017–2020.
explainer · evergreen
Applied Science explains how retail anti-theft tags work. A tiny magnetostrictive strip acts as a mechanical oscillator excited by a magnetic field, and magnetizing or demagnetizing it arms or disarms the tag.
HN recommends it as an informative explanation of what those tags are, especially in threads about implants and RFID.
“here's an interesting and informative video from Applied Science on how these tags work”
3 Hacker News comments link this video. Each one links back to its thread.
Right, which is precisely why automatic doors are completely irrelevant. On a related note, here's an interesting and informative video from Applied Science on how these tags work: ▶ this video
in “Why People with Brain Implants Are Afraid to Go Through Automatic Doors” · View on HN
Those RFID tags are pretty minimal though. Basically just a thin trace antenna and silicon die directly molded into plastic. ▶ this video I still agree that it's amazing that our society can make functional structures with feature sizes in the nm/µm ranges so cheaply that we can afford to throw them away.
in “ACE: Apple Type-C Port Controller Secrets” · View on HN
Are you sure these tags are RFID? I have only ever seen magnetostrictive tags [1] (but I don't buy expensive clothing...). [1] - ▶ this video
in “Alarm over talks to implant UK employees with microchips” · View on HN