Multiple motion detectors to one light
Is it possible to wire more than one (probably two) motion detectors to one light? The problem I am having is that if I set the detector to turn the light on for someone approaching the door, then when people exit the door it is dark, or vice versus.
Basically, a three way switch for motion detector is what I want.
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While others will reply as to whether the detectors can be directly wired to the lite, cuz I don't have a clue; consider a couple of relays. Each relay can be tripped by a detector and will pass a current to the light. Seems like it ought to work, other will know for sure.
One easy solution would be to get another complete motion sensor fixture and put it where it is needed to cover one of the approaches.
Another solution I have used is to separate the motion sensor head from the fixture and remount it somewhere else where it alone covers multiple approaches.
This remote sensor can also be used to activate more than just the fixture it originally controlled.
I want to avoid a second light on the front of the porch, just for appearance sake. It's only about 20' from the door all the way out to the sidewalk. I just can't aim a single detector at both the front steps and the front door.
You don't want a 3 way, because that would mean that while either one would turn the light on, it would also mean that either one would turn it off.
If the motion sensors are equipped with a timer, ie, motion turns the light on for a set period of time, then all you want to do is put two sensors in parallel, so that either one turns the light on for x minutes. You aren't depending on the motion to turn the light off, simply to turn the timer on for x minutes. So if the other motion detector detects motion as well, it will simply kick in for x minutes, some of which may overlap the first one.
Sounds like a simple "OR" circuit. The "trick" of such things is in the doing, though, isn't it?
I'm going to just guess that the layout would be best described as a "T," rather than like a more-typical 3-way switch layout, too.
I have four large carriage lights on ten foot poles running down my 100' driveway. I put a motion detector on the post near the street that looks toward the house so when I pull in (and come even with the detector) the lights come on and a second motion detector on the post nearest the house that also looks at the house so when you exit the front door this also turns on the lights. Due to the length of wire, the motion detectors are on a separate circuit than the lights themselves and, as Norman suggested, energize a relay which then switches on the lights. I think I have both motion detectors connected to the same relay.
With two motion detectors feeding the same light if either or both activate the light is lit. While this switching isn't common in residential wiring, there isn't anything wrong with it.
A central bath exhaust fan for multiple bathrooms is essentially wired the same way. Each bathroom has a timer switch and turning any of the switches energizes the single exhaust fan. No relays required.
I know that some can be, probably most will work.
Used to have a link to a company that made all kinds of motion sensors for commercial applications.
Many of them where used as occupancy sensors.
They often showed them being wired with there outputs paralleled just for reason that you mention. One application that was shown was to replace 3 -ways switchs in stairwells.
One at the top and bottom with the outputs wired together.
And some of the HD/Lowes are speced to operator other lights. They have a relay in them. Those definitely can be paralleled.
But I think that any can.
And there is X-10 that can do this.
Here is a wireless motion sensor. Don't know if you could have more than one on the same channel or not.
http://www.amazon.com/Designers-Edge-L-940/dp/B000A79I1K/sr=1-15/qid=1156987003/ref=sr_1_15/102-1554572-2229759?ie=UTF8&s=hi
http://www.amazon.com/Skylink-Household-Motion/dp/B0006BCCA4/sr=1-22/qid=1156987003/ref=sr_1_22/102-1554572-2229759?ie=UTF8&s=hi
http://www.amazon.com/Add-On-Motion-Sensor/dp/B000BHFDUO/sr=1-49/qid=1156987119/ref=sr_1_49/102-1554572-2229759?ie=UTF8&s=hi
http://www.amazon.com/Zenith-Wireless-Motion/dp/B000B67Z24/sr=1-80/qid=1156987219/ref=sr_1_80/102-1554572-2229759?ie=UTF8&s=hi
And these are standalone sensors.
http://www.amazon.com/Designers-Edge-L-99BR/dp/B0006OG9R8/sr=1-16/qid=1156987003/ref=sr_1_16/102-1554572-2229759?ie=UTF8&s=hi
http://www.amazon.com/Motion-Detector-/dp/B000CBTD8C/sr=1-13/qid=1156987005/ref=sr_1_13/102-1554572-2229759?ie=UTF8&s=garden
http://www.amazon.com/Motion-Detector-/dp/B000CBTD8M/sr=1-19/qid=1156987005/ref=sr_1_19/102-1554572-2229759?ie=UTF8&s=garden
http://www.amazon.com/VISONIC-INC-Outdoor/dp/B0007PANN2/sr=1-56/qid=1156987119/ref=sr_1_56/102-1554572-2229759?ie=UTF8&s=hi
http://www.amazon.com/Desa-International-Heat/dp/B00002N7FQ/sr=1-22/qid=1156986647/ref=sr_1_22/102-1554572-2229759?ie=UTF8&s=hi
Yes, it's possible. The ones I bought even included the wiring diagram to hook two detectors to one light.
That said, it never worked for me. One detector shows it is picking something up (red indicator light), but never starts up the spotlight. Other detector is fine.
No, you do not want a "three way motion sensor."
A motion sensor is switch. If you wan any detector to make the lights operate, you wire them up in parallel- just as you would with a switch.