Output of the motion detector RF front end is an analog signal as delivered by the mixer circuit. It can be best processed by an µC ADC input. For direction sensitivity, you need a quadrature mixer frontend with two outputs, by the way.
To my knowledge there are 3 main blocks to it:
I guess the antenna is the left side PCB trace: do you have any idea about the frequency of operation? The transistor is the oscillator and mixer?
I am just curious.
Yes. Antenna is left side. It's double sided and usualy has some funny shape. IIRC this one has some kind of circle on the other side.
These things work by splitting the output of a UHF/Microwave oscillator into two paths. The majority of the signal is radiated by the on-board antenna, a small amount is fed to a mixer. Signals reflected back to the antenna are also sent to the mixer. The mixer produces an LF signal consisting of the difference between Fosc and the reflected signal. If there is no movement in the near vicinity the signals will be the same frequency but due to the extra distance traveled along the reflected path there might be a phase shift between them. The phase shift produces a steady DC voltage from the mixer.
I've found datasheet of RCWL-0516 module:
It seems to explain everything.
Does it go through the wall?
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