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[caprox]

I have just installed MS14A motion sensor to control front porch light. Although the spec says the sensor can detect motion up to 20 ft, I have found that it works only up to about 5 ft. Could this be because the outside temperature is so high (I am in Texas so even in the evenings the temperature is in the 80s)? If so, is there any way to increase the sensitivity of the sensor? Thanks.

[steven r]

...the spec says the sensor can detect motion up to 20 ft, I have found that it works only up to about 5 ft. Could this be because the outside temperature is so high...

Many of us would be thrilled to be able to tune down our sensors. I ended up having to aim mine straight down.
I haven't heard of heat affecting distance.

[TakeTheActive]

...Although the spec says the sensor can detect motion up to 20 ft, I have found that it works only up to about 5 ft. Could this be because the outside temperature is so high...

Yes.

...is there any way to increase the sensitivity of the sensor?

No. (AFAIK)

Explanation:

These sensors work by detecting a heat change between their "Zones". If you look closely at the curved plastic window on one, you'll see MANY separate rectangles - they 'focus' the sensor into separate 'Fingers' (like spokes from a wheel). If the sensor is, let's say, pointing at your house and it's a 100 degree day - all the "Zones" are reporting 100 degrees. If you walk past the sensor, at 98.6 plus or minus, you're not much different than the wall of your house. Now, if the sensor *STILL* doesn't detect you during the 80 degree evenings, you "could" try carrying a metal teapot full of boiling water with you.

Personally, I only have 1 Battery-Powered Motion Sensor outside - an old MS12 inside my mailbox to alert me when the mail has arrived. Besides the lowered battery voltage in the winter, the RF range of the Battery-Power MSs is limited - I had to place a RR501 in the closest indoor outlet to receive it's RF. Also remember, MANY houses have foil-backed insulation.   

I prefer using the hard-wired PR511. When I installed my first (actually a HeathKit SL-5320 ) *YEARS* ago, I just followed the instructions. But, when I installed my second a few years ago, I wired the SENSOR separate from the FLOODS (blue wire, IIRC). This gives me *MUCH* more flexibility.

I have the SENSORs (Motion and Photo) on my MOTION DETECTOR HouseCode and the FLOODs on my LIGHTS HouseCode (so they flash when the PS561 Personal Security Console is tripped) - I use the Photo Sensor for Dusk/Dawn Macro operations (didn't want to waste precious memory in my CM11A ) and the separate Motion Sensor allows me to use the PR511s like the more expensive Leviton model - when the backyard Deck (or front Driveway) sensor trips, it turns on:

• Shed Floods*
• Deck Floods
• Kennel Floods*
• Driveway Floods*
• Garage Globe*
• Front Door Globe*
• Inside Garage Tungstens*
• Inside House "Motion Detected" Indicator Lights (DR and BSMT)*

The lights with '*' originally belonged *ONLY* to the DRIVEWAY PR511 which (still ) has everything on the LIGHTS HouseCode. [Need to find another .  ]

[TakeTheActive]

Many of us would be thrilled to be able to tune down our sensors. I ended up having to aim mine straight down.

Aren't you replying to exactly the OPPOSITE of what caprox is asking?

...I haven't heard of heat affecting distance.

My "theory" is that when 98.6 caprox is closer to the MSxx, he's changing more "Zones" simultaneously and even though the change is small, the logic in the PIC accepts it. [This same logic "might" be what rejects a xx degree bird or squirrel (fewer "Zones" than a human) moving past the sensor in the winter?  :- ]

[caprox]

Thanks TakeTheActive! Your explanation makes perfect sense! You mentioned hard-wired sensors. But they don't solve my problem, do they? Do you know of any sensors with ajustable sensitivity? Thanks again

[steven r]

Many of us would be thrilled to be able to tune down our sensors. I ended up having to aim mine straight down.

Aren't you replying to exactly the OPPOSITE of what caprox is asking?

...I haven't heard of heat affecting distance.

No just a soap box observation from my own and others experiences. My 2nd sentence was my responce.
I didn't realize the motion detectors sensed heat. That being the case I can see how a hot day might affect them.

[TakeTheActive]

Thanks TakeTheActive! Your explanation makes perfect sense!

You're welcome!  Did you find my explanation "Helpful" ?  [HINT, HINT, HINT... ]

...You mentioned hard-wired sensors. But they don't solve my problem, do they? Do you know of any sensors with ajustable sensitivity?

...Personally, I only have 1 Battery-Powered Motion Sensor outside - an old MS12 inside my mailbox...

...I prefer using the hard-wired PR511...

When an "Experienced X-10 User", IMHO  , replies to a question, 'sometimes ' it 'might ' be to your benefit to do some further RESEARCH. 

[caprox]

Thanks again. Yes, that was very Helpful!