Can Light Trigger a Motion Detector?

Exploring little known facts about what sets off motion detectors. 


August 26,2020

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Even with the best security system  on the market, glitches and problems can still occur. One of the most common issues is when a motion detector is triggered by something other than motion. Sometimes these sensors seem to alarm when there’s nothing there. This may cause them to turn on a light or other device — such as a camera — that they’re programmed to activate when they detect motion. So, why does this happen? Is it “seeing” that’s really not there? There are several explanations, and most of them are easily fixed. 

First, it’s important to consider that  light may be triggering  the detector. Since it senses patterns of light and shadow to determine whether there’s movement in the area it’s covering, it makes sense that those changing light patterns would be enough to set off the detector and the other devices its tied to. Other naturally occurring incidents that can set off your motion detectors are dappled patterns, such as sunlight through moving tree leaves, dust being caught in a sunbeam, or slow-moving light changes, such as the sun moving across the sky. While these instances usually aren’t enough to cause a motion detector to go off, you shouldn’t rule any of them out.  

Therefore, a motion detector’s is placement is critical, as  it may end up being triggered by something that doesn’t really count as motion at all.  This can lead to a lot of false alarms and cause a homeowner undue, avoidable stress. 

Motion Detectors See More Than Just Movement 

A motion detector sees movement, but it relies on what that movement is doing. Namely, changing light or shadow levels as they go by. Because the sensors rely on these movements, it’s possible that the way a tree is blowing in the wind and casting patterns on the carpet can be enough to set off a motion detector. This can be frustrating, but the solution is usually just to move the motion detector to another location where it’s not picking up on light or shadow patterns that cause false alarms.  

However, if you absolutely need a motion detector in that specific spot, then you may need to turn down its sensitivity. Additionally, you could get heavier blinds or curtains that would diminish the light pattern. It’s a simple fix that could easily reduce false alarms and give you peace of mind. 

What Can Set Off a Motion Detector: Other Suspects 

Still wondering what can set off a motion detector? Another culprit is…heat. 

Some sensors can track infrared radiation. This means a motion detector will be able to detect a light has been turned on because of a shift in temperature. If there is a change in heat, your detector will react and alert you. To counteract these settings, refer to your user manual for guidance. 

How to Adjust Lighting to Reduce False Alarms 

With a  security system  that includes motion sensor light with camera, adjusting lighting to reduce false alarms matters. That can be done in a number of ways that don’t involve curtains or blinds. Removing objects that are reflecting light or causing patterns is one of the ways to do that, such as moving a tree whose leaves are creating issues or relocating a troublesome mirror. Another way you can adjust light is keep your home brighter during the day, so there’s less of a contrast between inside and outside light sources. 

Let Brinks Home Security ™ Help Address the Issue 

If you’re covered by Brinks Home, we may be able to help you adjust your lighting and motion detectors so that false alarms become a thing of the past. There’s always the potential for a glitch to occur, and sometimes the sensor may still trigger, but it should be a lot less likely to happen after adjustments have been made. Contact Brinks Home today to establish how you can get your equipment properly working for you and your loved ones. 

Interested in Home Security? 

Monitor every corner of your home with award-winning home security from Brinks Home. From motion detectors and indoor cameras to smoke detectors and smart locks, we have best-in-class equipment that keeps you and your family safe. We’ve been protecting homes and empowering our customers for more than 20 years, with locked-in rates and customizable packages that give them control over their home security… And because we don’t believe our customers should have to pay for things they don’t want, you can make sure you only have the products that are right for you.  

Interested in professionally monitored home security? Get a free quote from Brinks Home. 

 Lauren Slade is a Dallas based writer and editor.

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