PIR occupancy detector vs ceiling fan

[PaulD]

If I wanted to use a ceiling mounted PIR (pet resistant) as an occupancy detector in a room with a ceiling fan, will it work if the PIR can see the fan? If the fan motion creates a problem, is there any workaround? Use a wall mount PIR and keep fan out of PIR field of view?

 

[CollinR]

It's not the fan's motion it's the heat from the motor if the PIR can see through it's vents.

Use a dual technology motion and don't worry about it.

 

[Ryetree1]

PIR detects the change in IR. I don't believe the fan will generate heat fast enough to set off the PIR. Once the fan is on for a while the PIR will evaluate the heat produced by the fan as just a noisy condition in the room (like sunlight).

 

[Photon]

Perhaps you could power your PIR with a 9V battery, tape it to a pole, and try it in various positions before you start drilling holes. The Bosch Blue Line PIRs I'm using have an LED that indicates when it sees something. The LED feature is jumper selectable so you can disable it after all the experiments are done.

 

[PaulD]

Thanks. I was focused on the fan blade motion and was not thinking about the fact that IR is heat based.
I like the idea of using a pole to play around with position. However, I am working on sensor and wire placement in a new house so I will be stuck with whatever placement I choose.....unless you can convince my wife that poking new holes in her brand new ceiling to move a PIR is OK