How do the small security tags (usually stuck on with adhesive) work on things in supermarkets, like meats, dvds etc?
They don’t get removed after purchase, so how come that individual item doesn’t set of the alarms even though the tag is still on it?
In: Technology
The detectors at the doors send power the tag as it passes through them, when powered the tag emits a signal back to the detectors.
This is called wireless electricity, Nikolas Tesla came up with it, and many others have tried it on small scales. Think about how you can send and receive signals with with a small, low power, wifi emitter. Boost up the power of the emitter and you can power a low power device.
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