PIR Sensor Question

[Terry]

Can anyone point me to a good link or website that has technical
information on how PIR sensors work? I am thinking about using one to
sense the presence of a person or a pet, and want to know in detail how
they work, and what are the pro's and cons.

Thanks!

-Terry-

 

[Ross Herbert]

Can anyone point me to a good link or website that has technical
information on how PIR sensors work? I am thinking about using one to
sense the presence of a person or a pet, and want to know in detail how
they work, and what are the pro's and cons.

Thanks!

-Terry-

This patent document might give some idea

http://www.patentstorm.us/patents/6215399-fulltext.html

 

[David L. Jones]

Can anyone point me to a good link or website that has technical
information on how PIR sensors work? I am thinking about using one to
sense the presence of a person or a pet, and want to know in detail how
they work, and what are the pro's and cons.

Thanks!

-Terry-

Here is a great explanation and example circuit:
http://www.glolab.com/pirparts/infrared.html

Modern ones are designed *not* to detect pets, to prevent false alarms.

The new "dual PIRs" combine a microwave sensor with the traditional
PIR, in which both sensors must activate before the trigger is sent.
Once again to help prevent false alarms.

Dave