Mediocre Insteon Motion Sensor function in a hot room

[someguy]

I've got an insteon MS in my "gym" and it is mounted about 30 feet from the door of the room and when I walk in the gym, the lights go on instantly. It is impressive how quickly they go on. (I've got the MS linked directly to the lightswitches.)

 

I've got another MS in my garage. I put it about 30 feet from the door and the thing worked terribly. I had to move it over near the door. My garage is not air-conditioned and it gets pretty warm in there.

 

I am thinking of putting one on my front porch, but I'm concerned about the range of it. I could put it up in the "ceiling" of the porch, which is about 20 feet up.

 

Has anyone else noticed this, or is it possible that the garage MS that I have is bad?

 

thanks,

 

someguy

[Brian H]

You may want to read the information on the sales page.

The motion sensor detects motion by changes in detected IR emissions.

Heat does effect how well an object is detected.

 

One line in the description. PIR reliability may vary with temperature

 

http://www.smarthome.com/2420M/Wireless ... sor/p.aspx

 

Over in the X10 forums we see motion sensor and heat related issues with their sensors. As they use a IR Detection system.

[Sub-Routine]

Hi someguy,

 

I would suggest moving the garage sensor indoors and see if it works better.

 

If so try it on the porch. I have 2 outside sensors working. One in direct sun all day.

 

Rand

[IndyMike]

Hi Someguy,

 

I have a motion sensor in my garage as well and it does get quite warm in the summer (I doubt it's ever gotten to 98.6). These devices work on temperature differentials. If your body is cooler than the surrounding steady state temperature it should trigger on the motion. I'm sorry if your garage gets above your body temperature - If you've sent a summer party invitation, please accept my regrets.

 

I have had the exact opposite problem with my garage sensor. When I re-enter the garage with my winter parka (shoveling snow), it is sometimes slow to detect my nose sticking out from the hood. This I attribute to the heavy layer of insulation (down parka) that is close to the garage temperature and a short nose.

 

PIR motion sensors use a series of Fresnel lens segments to direct IR energy to the sensor. Looking at the lens segments on the SH sensor -

1) They are most sensitive to horizontal motion across the Fresnel lens segments.

2) They are less sensitive when oriented above an approaching object (utilizing the vertical lens segments - 3).

3) Least sensitive when on the same horizontal axis as the approaching object (directly in line).

 

In addition to the above, PIRs can be:

1) Saturated (overloaded) by direct or refracted light light sources (a window).

2) Unable to stabilize due to quick changing temperatures (air currents).

 

In general the sensors are most sensitive if they are aligned above (to eliminate incidental light) and off axis (not directly in line) with the approaching object.

 

My sensor is roughly 40' from the entry door to my garage (45 degree angle off axis - located at the ceiling). It is tuned to trigger on entry through the swinging door. Automotive entry through the overhead door is less sensitive, but we're talking about 4500 pounds of steel vs xx pounds of human (weight withheld to protect the old and inactive). Human entry through the overhead door suffers a bit due to the angles. Nonetheless, the sensor will detect someone trying to sneak past the cars (tested by a 14 year old).

 

If you're interested, there's a Wiki on the sensor technology here: PIR Wiki

[someguy]

thanks for the info, fellows. I'll use these ideas when I test out the new sensor on my porch.

 

someguy