Comments by "" (@Green__one) on "Passive infrared motion sensors: a two-bit camera powered by crystals" video.

  1. As you want to be able to track motion in multiple axis, I strongly suspect these are more than two crystals, so that you can capture not just side to side, but vertical as well
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  2. I'm almost surprised how many people see these things in a room, and think that they are cameras. I've had to explain to guests in my house that no, I'm not spying on them, I just have motion sensors activating some lights!
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