# How to rig a motion detector light
**URL:** https://boards.straightdope.com/t/how-to-rig-a-motion-detector-light/700963
**Category:** Factual Questions
**Created:** [October 10, 2014, 2:16pm UTC](https://boards.straightdope.com/t/how-to-rig-a-motion-detector-light/700963 "2014-10-10T14:16:40Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@Lucas\_Jackson](https://boards.straightdope.com/u/Lucas_Jackson)
#### Post date: [October 10, 2014, 2:16pm UTC](https://boards.straightdope.com/t/how-to-rig-a-motion-detector-light/700963/1 "2014-10-10T14:16:40Z")
The situation: In a complex that I manage, tenants using the laundry room always leave the light and fan on when they leave. The owners noticed this on a recent visit and I have been tasked with installing a motion sensor to prevent this from occurring.
I will be installing a new light/fan overhead. I’m looking for the simplest way to connect this to a sensor that will shut it off if the room is empty.
And yes I realize this might not save the owners that much but it’s his decision.
Ideas?
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### Author:  [@Sicks\_Ate](https://boards.straightdope.com/u/Sicks_Ate)
#### Post date: [October 10, 2014, 2:29pm UTC](https://boards.straightdope.com/t/how-to-rig-a-motion-detector-light/700963/2 "2014-10-10T14:29:04Z")
A switch with an occupancy/motion sensor may meet your needs, and would be simple to install.
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### Author:  [@excavating\_for\_a\_mind](https://boards.straightdope.com/u/excavating_for_a_mind)
#### Post date: [October 10, 2014, 2:43pm UTC](https://boards.straightdope.com/t/how-to-rig-a-motion-detector-light/700963/3 "2014-10-10T14:43:43Z")
One problem you may face (I don’t know the layout of the laundry room) is that if you put the detector in a location where it detects someone entering the room, there may be “blind spots” in the room, meaning the room could be occupied, but the lights turn off because the detector cannot detect them. This could be rather annoying to someone who was sitting in the corner reading a book while the machine was running. This can be addressed by setting the delay (the amount of time the lights stay on once the detector has been activated) to ~45 minutes. It is unlikely that someone would stay in the blind spot for longer than it takes to run a load of clothes.
Another issue is that if you set the sensor too sensitive, the air conditioning and/or a running washer or dryer may set it off.
FYI, I have a motion sensing light switch in the laundry room of my house. I installed it for exactly the same reason. An unexpected benefit was that I don’t have to fumble for the lightswitch when I enter carrying a load of clothes. The laundry room is located right next to the kitchen and sometimes, when the oven is opened while it is hot, the lights will come on in the laundry room.
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### Author:  [@bob\_2](https://boards.straightdope.com/u/bob_2)
#### Post date: [October 10, 2014, 2:44pm UTC](https://boards.straightdope.com/t/how-to-rig-a-motion-detector-light/700963/4 "2014-10-10T14:44:38Z")
I would ask at your local electrical shop. This is a pretty common thing in these days of ever increasing costs. I think that your landlord may well notice the benefit.
You may need to comply with some code as this is in a communal laundry room.
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### Author:  [@johnpost](https://boards.straightdope.com/u/johnpost)
#### Post date: [October 10, 2014, 2:48pm UTC](https://boards.straightdope.com/t/how-to-rig-a-motion-detector-light/700963/5 "2014-10-10T14:48:02Z")
you can find units where a motion sensor is in the light fixture.
you can also find sensors that will replace the wall switch.
set the timer duration for 20 minutes or so, then if there are dead spots to the sensor, the person will keep reactivating it within that time.
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### Author:  [@LH75](https://boards.straightdope.com/u/LH75)
#### Post date: [October 10, 2014, 3:19pm UTC](https://boards.straightdope.com/t/how-to-rig-a-motion-detector-light/700963/6 "2014-10-10T15:19:26Z")
Home Depot has them, and they come with a wiring diagram for the installation
[motion sensor switches](http://www.homedepot.com/s/motion+sensor+switch?NCNI-5)
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### Author:  [@Lucas\_Jackson](https://boards.straightdope.com/u/Lucas_Jackson)
#### Post date: [October 10, 2014, 4:07pm UTC](https://boards.straightdope.com/t/how-to-rig-a-motion-detector-light/700963/7 "2014-10-10T16:07:48Z")
Thanks for the help - headed to Home Depot.
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### Author:  [@Reply](https://boards.straightdope.com/u/Reply)
#### Post date: [October 10, 2014, 9:59pm UTC](https://boards.straightdope.com/t/how-to-rig-a-motion-detector-light/700963/8 "2014-10-10T21:59:41Z")
Just a few quick comments (hopefully not too late):
1. If possible, you should look into those switches that have separate sensors you can wire into the ceiling, because that would give a better field of view than some random switch behind the door.
2. They also make motion-sensor light bulb socket adapters that you can install between a bulb and the socket, in the fan or whatever.
3. If you do decide to go with the wall switch kind, look for one that can has both infrared and ultrasound sensors, and a daytime/ambient light sensor (most have that) and preferably one that has no public-facing “off” switch, or at most one with a temporary, one-button off switch. A lot of people will turn off those motion sensors with switches because they find them annoying, which defeats the whole point.