Detecting Occupancy when motion is minimal

[maxnorth]

I haven't seen another post on this topic so here I go. I've got an Insteon motion sensor in my wife's 10 by 20 foot office and programs to bring the light on when motion is detected and keep it on so long as the sensor is active. The light is programmed to go off after 10 minutes with no motion. Works fine so long as she moves around regularly. The problem comes when she does some quiet activity, such as sitting at her desk with her back to the sensor, or sitting in a side chair while knitting or something.

 

I've thought about adding more sensors, and I may have to try that to know for certain, but my concern is that the Insteon sensor may not be sensitive enough even when pointed directly at a quiet subject. That seems to be the case with the current sensor, which is located about 10 feet above and behind her desk chair.

 

Are there any clever ideas for dealing with this, or different sensors I should be looking at?

 

Yes, I do have a program that enables her to "override" the timer by pressing the On button, but she often forgets to do that until it's too late, and her patience with me is running short. "Just waive your hands" is getting old.

[LeeG]

PIR motion sensors detect the movement of heat across the view of the motion sensor. If the heat source does not move as with an individual sitting or standing motion free, a PIR does not trip. Folks have discussed using a pressure sensor in the seat where someone would be sitting. Insteon does not make those but a pressure switch could be connected to an I/O Linc Sensor.

[larryllix]

Motion detectors do not detect motion going toward or away from them as well as across for logical reasons.

 

-Try moving the motion detector so that it can see her rocking forward or backward in her chair. IOW from the side of her and keep it close to her chair as possible so it occupies more sensor elements.

 

If she moves her hands to the keyboard or leans back or forward it should see that as bigger action/motion and do what you want it to do, mostly. It may not be seeing much movement from the back.

 

-Rotate the desk?

-Fasten the Motion detector to another inanimate object?

-Lengthen the timer?

-Make a timer algorithm that gets shorter at select times of the day? eg. when you know she should be leaving shorten the timer? Lengthen at key times when you know she may be still?

-Dim the lights and back as a warning before shutting them off a few minutes later. Gives her a chance to "waive her hands" and reset the timing before pissing her off in the dark.

[switches]

Have the light switch beep every few seconds for 30 seconds or so to give a chance to move before shutting off.

 

Increase the timer from 10 minutes

 

If she happens to turn something on when in the office add a synchrolinc so the timer doesn't count down if that device is turned on