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How do these things work?
How do They detect that someone is in the room?
How do Light detectors work?
I don't care about circuits or what they do once they detect something i'm talking about the very tiny part of it that detects light/something, how does that happen? A chemical reaction? Something with magnetic fields?
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>>8728862
>i'm talking about the very tiny part of it that detects light/something
Nowadays it's mostly CCDs. Something with semi-conductors and band-gaps.
Earlier the photoelectric effect was used (and amplifiers).
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>>8728877
Thanks Holy Kek.
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>>8728862
They use passive infra red sensors and algorithms that look for a fast changing value. Any warm body gives off IR. The sensor is a phototransistor like what picks up a TV remote but a lot more sensitive.
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>>8728862
They got electricity and wires and things running through em. The electricity probably makes that red light go on and off I think
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