How microwave body detectors work. With RF section schematic.

When I first took a microwave triggered lamp apart in a video I joked about the hidden chip being a standard PIR body sensor chip – and was then aghast to find that it WAS. Which meant that all the microwave signal generation and movement detection was being done by a single transistor and some cunningly designed PCB tracks.

I’ll openly admit that microwave circuitry is such a specialist area where the only people who truly understand it are those who work with that type of circuitry all the time. It’s not just a specialist area of electronics, but a specialist subsection of RF design where simple things like tracks stop behaving like conventional conductors.

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