What is a Motion Sensor Lamp?

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  • Written By: Daniel Liden
  • Edited By: Jenn Walker
  • Last Modified Date: 03 November 2019
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A motion sensor lamp is light-producing device that activates in response to motion. Sometimes, a motion sensor lamp is simply used as a convenience and will turn on when one enters a commonly-used room, such as a restroom. Upon activation, such a lamp will generally remain active until a certain amount of time has passed in which it has not detected motion. Such lamps are commonly used to reduce electricity costs as they automatically turn off when people aren't present rather than remaining constantly active. Motion-activated lamps are also commonly used outdoors for guidance and for burglar deterrence.

In most cases, a motion sensor lamp works through optical detection, meaning that sudden changes in external light or visual input generally trigger activation. Usually, this does not involve changes in visual light because such devices are often used in places that are subject to total darkness. They instead use lasers or infrared light; when a person or object passes into or through the laser or infrared light, the motion sensor lamp will activate. Continued motion in the detection area will cause the light to remain active, while a cessation of motion will cause the light to deactivate after a set period of time.


To ensure the light only activates when needed, it is important that the sensor is well placed and that the area of activation is well defined. If one wants a motion sensor lamp to activate when someone approaches his front door, for example, he should also try to make sure the light does not turn on every time someone walks past his house on the sidewalk. The light would probably irritate neighbors, frighten passers-by, and waste energy. To minimize accidental activations, a motion sensor lamp may have a time delay mechanism so that a moment of motion at the edge of the sensor area does not activate the light.

A motion sensor lamp can serve as a highly effective burglar or intruder deterrence system, as the sudden activation of a light reveals the intruder's activities and suggests to the intruder that he is being monitored. In some cases, a camera will be activated at the same time as a motion sensor lamp in order to record the activities of an individual passing through the sensor area. If the sudden activation of the light does not frighten the intruder away, the camera can help law enforcement officers to find the intruder and to verify his identity in court.


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Post 13

Have you ever come across a situation where one person always activates outside motion sensor lights, yet no matter how much the other person waves or moves into several positions around the lights, she never activates the sensor lights?

Post 12

@Sara007 - I don't know if you had to put in large motion sensor lamps or not into your kid's room, but you can also buy night lights that activate with a motion sensor. We have them installed in our hallways and bathrooms because we were always tumbling over things in the middle of the night.

Our cats are the worst. They love to sleep in the darkest part of the house possible, which used to be along our hallway upstairs. More than once one of us practically fell over the kitty. With the night lights installed whenever we walk down the hall they turn on, preventing any unpleasant mishaps.

Post 11

My kids are afraid of the dark so we installed a motion sensor light just beside their beds. Pretty much it is angled so that you have to wave your hand near it in order for it to light up the room. It took us quite a bit of manoeuvring to set it up in a way that wouldn't have it turning on and off every 5 minutes.

My girls really appreciate the motion sensor lamp though. If one of them has a bad dream it is just a matter of waving their hand in front of the light and they can see that everything is as it should be.

I would recommend these kinds of motion sensor lamps for anyone that has children who have trouble sleeping in the dark room. The easily available light gives them an extra bit of security.

Post 10

My friends put a motion sensor light in the kitchen - I thought this was brilliant for late-night fridge raids.

Where are some other good places to put motion sensor lights?

Post 9

When my husband and i moved into our first house, my husband was set on getting motion sensor lights outside that would go off when we came home and exited our cars.

I did not share his excitement and with all the expenses that moving into a new house comes with I was ready to buy some more decor as opposed to non decorative lights!

However, as a compromise I relented and we now have an outdoor motion sensor light and I love it! I would trade in my decorative pillows (which I love) for a new one if we needed it.

I did not realize how much of a pain it was to get out of

my car, try and find the house key out of my multitude of keys and key rings in the dark, and about a month after we lived there I was up close and personal with how much of annoyance it was.

That is about when the motion sensor light was installed and viola! no more fumbling at night! Love it!

Post 8

There is a walkway from our driveway to the front porch that I lined with solar motion lights.

I wasn't sure how much light these solar lights would give off, but they were decorative and functional and so decided to give them a try.

On the days when we have quite a bit of sun, they do a good job of illuminating the walkway. If there are several cloudy or rainy days, the light is still there, but it is pretty dim.

Since I have overhead lights above my garage and front door, the solar lights add more of a decorative look than anything, but the convenience of the motion light is nice.

Post 7

You have to walk up a few steps to get to our front door. Since we live in the country and don't have any street lights, it can get very dark outside at night.

We put a motion sensor porch light on each side of the steps going up to our door. We usually go in and out from the garage door, but when company comes, they always use the front door.

It is very handy to have these lights automatically come one when someone approaches these steps. This way you don't have to worry about making sure you have a light turned on, and don't have to think about remembering to turn it off.

Post 6

We have an outdoor motion sensor light installed right above the side door on our garage. This has come in handy so many times.

There are many times when I have my hands full and am trying to get my key in the lock to unlock the door. Once I approach the door, the motion light automatically comes on so I don't have to feel around in the dark looking for the keyhole.

We also keep our garbage can and recycle bin right by this door, so when you go outside at night to place something in the bin, the light automatically comes on so you can see what you are doing.

Post 5

@MrMoody - I think if you really want to come up with various ways of mixing different technologies, you should probably shop from online spy gadget stores instead of just looking for motion sensor units from a hardware store.

The array of possibilities they offer will provide you with a wealth of creative security solutions you can use out of the box, or integrate into your own homespun setups in my opinion.

Post 4

@SkyWhisperer - Yeah, there is practically no limit to the ways you can combine different technologies with motion sensor security systems.

If you’re particularly handy you can buy a simple motion sensor switch that you plug into your wall outlet. Then, attach whatever appliances or devices that you want activated whenever the motion sensor circuit trips.

You could wire up your own digital camera, lamp, siren or even a webcam that will not only take the picture but transmit it online. I think the sky’s the limit.

Post 3

@miriam98 - I believe that there are actually quite a number of options you can buy these days with the motion sensor security.

I found these units on the Internet which not only have the motion sensors, but also built in digital cameras. They will take pictures of the intruder or whoever is passing by when the sensor is activated.

I think they operate in a way similar to the units mounted on some traffic lights which take pictures of speeding cars. Anyway, the pictures are stored on SD cards so that you can upload them to your computer later for analysis, or give them to law enforcement when reporting a crime.

I think that these are really useful and would be better than simple motion sensor lamps or alarms.

Post 2

@EdRick - I think that another good option to consider is motion sensor alarms. I bought a couple of these in the first house I owned. You can buy them as standalone units, without needing to have them professionally installed as you would with a monitored alarm system.

They operate by the same basic principle as the motion sensor lamps. They detect motion, which I think the unit does by measuring body heat in the vicinity of the unit. Then they set off an ear piercing alarm.

They’re not monitored systems, so they won’t call the police, but does the thief know that? I doubt it. In most cases, simply the sound of the siren is enough to cause him to flee.

Post 1

Another advantage of motion detector lights is that they reduce the spread of germs. I think that's why my doctor's office has them. When you enter the room, the light turns on.

The problem there is that when you've been very still for a while (i.e., because you are on the table with your feet in the stirrups), the light turns off. Then it's too dark to read your book!

If I happen to be not naked, I have resorted to opening and closing the door again so that my light comes back on. Seems to me like they need to reprogram them for a longer interval if they're going to keep people waiting around for quite that long!

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