On: Inside a $1 radar motion sensor

[Avamander]

There are some that detect heartbeat, I guess those might work. But those are mmWave, not just cheap 2.4GHz radars or PIR.

[stavros → Avamander]

I've got LD2410B, which are mmWave, so they should detect heartbeat (and do), but not from more than 2-3m away.

[transpute → stavros]

Is the LD2410B sensing range limited by the PCB antenna?

[stavros → transpute]

I'm not sure, it always just made sense to me that the farther away someone is, the harder it'll be to detect their small movements.

[transpute → stavros]

Smallness detection depends on RF: higher frequency = shorter wavelength = more resolution for imaging.

Detection range without obstacles depends on transmit power and signal reception.

There are other models in the same family which might have more power/range.