PIR signal processing

[Dunce]

Hi,

I wonder if someone might be able to point me in the right direction, bit of a specialist one this I think

I'm looking to build a PIR movement detector project, but with a slight difference. I need the PIR to be able to distinguish between large and small 'heat' masses, in a similar way that a 'Pet safe' sensor does (on a typical home alarm for example).

The difference being that I'd like to be able to change/tweak this "setting" as required and detect either a large, or small heat source.

Does anyone know how this might be accomplished? Would this be a case of adding some kind of processing that would be able to test the signal and respond approprietly (i.e. ignore a small heat source), OR would there be some other way to approach this?

Any shoves in the right direction would be very welcome, thank you.
---
MRB

 

[tonigau]

Hi MRB.
Sounds like you know more than me, I havent heard of the "pet safe" sensors, then I havent played with PIR detectors for many years.
Are they definitely PIR & not ultrasonic.

As pets are generally smaller than us hyoomans (unless you have a pet cow or horse inside) then the IR emission area will be smaller relative to the sensor coverage area. So maybe the design of the fresnel lenses is significant ?, but then size is relavent to distance from the sensor or maybe the intensity of IR ?.

Humans have a lower body temperature than dogs & cats, maybe the sensor has temperature sensing as well. but then insulation(fur) variations will probably affect this measurement.

All speculation on my part, maybe someone else has some ideas or actually knows how these specific type work.

There is a fully automated system in australia that uses video & a laptop with image processing to distinguish different animal types to help manage feral & stock control.
The computer controls a gate that directs animals into or out of an area.

You could try calling some security system manufacturers.

Tonig.au

 

[Dunce]

Pir

Thanks for the thoughts, I have a sneaky feeling it's set at a lens level, awaiting some manufacturer repiles.

Thanks again,
Mark

 

[kalpanasinma]

can anyone post the circuit for PIR security system with mobile alert?? please please... i have review on monday