ChatterBank3 mins ago
employee badge
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how does a employee badge work
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No best answer has yet been selected by pareshnj. Once a best answer has been selected, it will be shown here.
For more on marking an answer as the "Best Answer", please visit our FAQ.I suspect you mean some kind of automatic gadget which makes doors open for the right people?
It probably has a transponder chip in it. Near the door is a radio transmitter sending a coded message. The transponder chip uses a tiny bit of the radio energy to respond with a very weak coded radio message, detectable by a receiver nearby. If this code is correct, the door opens.
The anti-theft gadgets in shops work in a somewhat similar way, and so do the identification chips implanted in pets.
It could perhaps also be a more sophisticated circuit, with a battery and programmable code.