There is no difference between a standard IR detector and a "not pet IR detector " except the front fresnel plastic lens and the sensitivity, which is in fact the gain of input operational amplifier stage. This analogic signal is compared into a windows comparator. One pulse or multiple pulse are resolved with a simple RC integrator. I was talking about cheap IR detectors ( relay and tamper) and not those who are connected between on a smart bus. You may built yourself if this is your passion, buy from EG&G Heimann a pyroelectric infrared sensor with built in filter at 5..14um vavelenght ( where human body radiation is maximum ) You may choose from a large range of infrared sensors. You need also a low noise operational amplifier, a comparator, and a lot of working... Vasile On Tue, 27 Feb 2001, Simon Ethier wrote: > Any idea on how to build this ? > > thanks > --- > Simon Ethier > sethier@justine.umontreal.ca > ICQ 66019153 > > ----- Original Message ----- > From: "Ray Russell" > To: > Sent: Tuesday, February 27, 2001 11:41 AM > Subject: Re: [EE]: Infrared Detector vs Pet > > > > In a message dated 2/27/01 11:10:08 AM Eastern Standard Time, > > Seth889@STARTREKMAIL.COM writes: > > > > > > > Hi, I'm wondering.. I heard in a publicity of an alarm company that they > > > have an infrared detecter which can make the difference between pet and > > > human (how, I don't know ... ok it don't really "make" the difference, > but > > > the IR won't react to a cat for exemple, but will react to a human) I > found > > > this very cool, especially if you have pet at your house... > > > > > > I'd like to build something like that ... Do any of you guys know what > is > > > the trick ? Is it less sensitive ? Does it require a minimum of > movement > > > ... > > > > > > > > > > Simon, > > I use these detectors in my shop. They produce a multi path beam. Multiple > > beams must be broken in both directions to set them off. We had a problem > > with rodents getting into the shop. (We are in the country so field mice > and > > rats are common) > > They kept setting off the old detectors. Even the mouse traps would set > the > > darn things off. The new ones are very sensative to humans but cats and > mice > > seem not to bother it at all! > > > > Ray Russell > > General Contractor > > Norfolk & Western Railroad > > > > Pocahontas Division > > Circa 1958 > > Visit The Pocahontas Website at: > > HREF="http://milliron.home.sprynet.com/Pocahontas/Pocahontas1.htm">Click > here: Pocahontas Home > > OR > > http://milliron.home.sprynet.com/Pocahontas/Pocahontas1.htm > > > > -- > > http://www.piclist.com hint: The list server can filter out subtopics > > (like ads or off topics) for you. See http://www.piclist.com/#topics > > > > > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics > > -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.