Talk:Passive infrared sensor

message: Can the bionic infrared sensor developed by Dedy Wicaksono (TU Delft) be mentioned ? http://dedywicaksono.wordpress.com/2008/10/21/my-phd-research/  —Preceding unsigned comment added by 81.245.64.190 (talk) 11:11, 8 July 2009 (UTC)
thread_title:  Bionic sensor 

message: The prefix infra does not mean below our ability to detect it visually but simply means below.  Otherwise other words with this prefix, such as infrastructure and infrasonic, would not make sense.  Infra-red simply means below red and refers to light that is lower in frequency than red light.  —Preceding unsigned comment added by 203.35.135.136 (talk) 03:10, 15 September 2010 (UTC)
thread_title:  Infra 

message: The sensor does not measure heat of objects entering the field, it captures a virtual map of the surroundings based on heat signatures and ANYTHING entering that field will disturb the field and activate the sensor. It doesn't matter what temperature the moving object is, it could be exactly the same temperature as everything in the field. I made an edit but just added two sentences to clarify. I work in IED defeat (Counter IED) for the military and am trying to get them straight on this as well.  — Preceding unsigned comment added by Mcgyver2k (talk • contribs) 16:37, 29 September 2011 (UTC)
thread_title:  Misleading first paragraph 

message: Do anyone have any information about the history of PIRs, such as when they were invented and were first used in alarms?  — Preceding unsigned comment added by 130.235.35.168 (talk) 09:43, 15 February 2012 (UTC)
thread_title:  History? 

message: The article says two things which seem confusing to me - I can't see how they can both be true. 
1) "Strictly speaking, individual PIR sensors do not detect motion; rather, they detect abrupt changes in temperature at a given point using the Infrared radiation level"
2) "Moving objects of identical temperature, however, will trigger a detection because that is the sensor's job, to detect motion. It detects motion regardless of temperature.[4] This is also why you can take a piece of paper from a desk that is the same, exact, temperature as everything in the room, attach it to a stick (also the same exact temperature as the room) and wave it slowly in front of a sensor (at any range within the limit of the sensor) and it will activate the sensor."
If objects of the same temperature are moved, how is motion detected? Could it be due to different emmisivities of materials? If that is so, and that is my best guess, it should be stated. But I have no idea if that is so.  Drkirkby (talk) 09:06, 3 June 2013 (UTC)
thread_title:  Can a PIR detector detect moving objects at a fixed temperature? Article says so, but does not explain  

message: I'm not the ideal person to write this but if someone closer to the PIR industry could that'd be great...
In practical terms, real-world PIR detectors of the type described have various tricks to avoid false alarms. For example, additional volumetric sensors can be added to confirm what the PIR sensor is seeing (called Dual-Tech sensors). I use "quad element" sensors, which have a higher immunity to false alarms (from manufacturer's claimed, and experience), and I guess they have four sensors in one housing but I don't really know.
There is also optional temperature compensation, claimed to improve accuracy.
F J Leonhardt 13:06, 25 September 2016 (UTC)
thread_title:  Different practical types such as Dual Technology, Quad and so on 

message: Said paragraph currently includes "and fed to a transistorized relay driver circuit."  Really?  Always??  I would think that in many cases nowadays, the switching would be electronic rather than electro-mechanical. 94.30.84.71 (talk) 10:19, 7 November 2019 (UTC)
thread_title:  Practical Implementation 

message: The lede says the "P" means passive.  Some say it means pyroelectric.  Is one more correct than the other?  Should the pyroelectric hypothesis be mentioned as well?  Oh, and there is no link to Pyroelectricity in the article!  I am shocked!  Shocked, I tell you! :-) 85.76.78.82 (talk) 14:51, 4 September 2020 (UTC)
thread_title:  Passive or pyroelectric