PIR sensor teardown

This is a tear-down of an interesting PIR (passive infra red) sensor found from some unknown light system believed to be powered from 230V AC.

The chips used seem to be ST LM2904 low power opamp and TFK U2100 timer control chip. The sensors are PIR sensor and LDR.

The most interesting part is that most of the “circuit board” is not made of traditional circuit board material, but instead pieced of metal put inside plastic material.



This can be bent open quite easily to reveal all that is packed in there.



What was revealed was relay, adjustment potentiometers, over voltage protection VDR and transformerless power supply components.


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