Occupancy Sensor Placement

[sionxct]

I've read some posts here where folks are using PIRs tied to their Omni for occupancy detection. I've read where using PIRs for both occupancy and motion are not a good idea, since they operate with different assumptions. Can I assume then, that those mixing their PIRs are placing occupancy sensors in rooms where occupancy detection is important, and motion sensors in areas where security is the priority, and that the Omni can be programmed to ignore occupancy sensors when the system is alarmed?
 
I've seen a guide on choosing locations motion detectors. Are there any guides for occupancy sensors? My experience with occupancy sensors is the location needs to be adjusted until you fins a "sweet spot." But, if they are hardwired to an Omni, thats not so easy to do.

 

[ano]

While occupancy detectors and security motion detectors are in fact different as you say, and clearly you want motion detectors for security, you really have to ask yourself why you REALLY want occupancy detectors?  I have maybe 15 motion detectors through my house for security, and they do set a room and a house occupancy flag, but that its about it.  If you plan on using occupancy sensors to turn off lights after a period of "no occupancy" your going to be disappointed. The best occupancy sensors don't perform this task with much precision.  For the coarseness that occupancy detectors actually provide, you will get 99.9% of the bang out of just using security motion detectors.  
 
In one or two parts of my house, motion will turn on lights, but because of time delays, I only do it when the light is considerable distance from the motion detector.  Even then, without some logic, it can be real annoying, often with the light turning on after i just shut it off because I am now leaving the room. 
 
For the most part, controlling anything based on "occupancy" is likely to end in frustration. Seems like a good idea, but in most cases, it just isn't. You probably don't believe me on this, but after you attempt it and it doesn't work great for you, make sure you report back here. There are certainly some good uses for occupancy, but none that motion sensors can't perform just as successfully.

 

[mikefamig]

I am very happy with a Leviton occupancy sensor in my garage. It turns on the lights when the overhead door moves or anything moves in the garage and also has a manual button that overides the sensor. It is configurable but only to a point. If it's built-in logic works for your application then great. Read the documentation twice before buying any device.
 
You can use PIR motion detectors with your automation panel to do the same job but you will have to write complicated rules to do the same job that the occ sensor is capable of.
 
Mike.

 

[ano]

I am very happy with a Leviton occupancy sensor in my garage. It turns on the lights when the overhead door moves or anything moves in the garage and also has a manual button that overides the sensor. It is configurable but only to a point. If it's built-in logic works for your application then great. Read the documentation twice before buying any device.
 
You can use PIR motion detectors with your automation panel to do the same job but you will have to write complicated rules to do the same job that the occ sensor is capable of.
 
Mike.

I use that sensor in my garage and a few places, and it works reasonably well. My wife would disagree though and always complains that the light is on for too long. She then manually turns the light off, in which case if i go in the garage soon after, then the light won't go on because it has a lockout period when you turn it off.  The good part about it is that it has logic to determine if you go in the garage for a quick time, or its a longer time. That logic would be pretty hard to duplicate using logic on a panel, but you could try.
 
Motion detectors work generally well in situations where there are lots of motion and where your length of stay is generally short like an garage or hallway. They work less well in a room you stay much longer in and may move around less like an office or family room.

 

[mikefamig]

I use that sensor in my garage and a few places, and it works reasonably well. My wife would disagree though and always complains that the light is on for too long. She then manually turns the light off, in which case if i go in the garage soon after, then the light won't go on because it has a lockout period when you turn it off. 

Mine has that same behavior but it hasn't been a problem very often and when it does happen we just turn the light on using the push button. One nice thing about it is that you can put as many push button switches on it n different locations as you like.