Overcoming 7 Common Microwave Sensor Lighting Problems

I’m all for automating lighting controls. They save fumbling around in the dark for an elusive switch and also prevent lights being left on wasting energy and money. That being said, motion sensor lights are not without their issues, that left unresolved, can drive you up the wall.

This post deals with the 7 most common microwave sensor light problems and how to deal with them. Reading before installing a sensor can save a lot of time and aggravation, or if you have already installed and are having problems, this post should point you in the right direction!

Motion sensor lights are pretty cool when placed in built-in wardrobes to help fumble around for clothes in the morning.

The 7 Most Common Microwave Sensor Light Problems

1: Sensor Not Detecting Motion

The whole point of automating our lights with sensors is to make our lives as easy as possible, so this kind of falls apart when the sensor fails to detect our presence. The motion sensor not detecting presence can be a common problem I come across.

Positioning and setting up the detection range of the sensor is perhaps the most important piece of the puzzle. The height it is mounted at has a lot to do with it, as the higher we can place it the more likely it is to detect us from a distance further away.

Just be careful not to go too high as we can end up causing the next problem which is a light that is overly sensitive and triggering all the time.

2: Overly Sensitive Sensor

Overly sensitive detection is perhaps the biggest bugbear of using microwave sensors compared with some of the other alternatives (you can read an article here comparing the pros and cons of microwave vs PIR detectors)

Aside from incorrect placement, one of the main causes of this nuisance is the fact that microwave sensors can detect through walls, through glass and even through some metal.

When a sensor is overly sensitive it triggers all the time causing a real nuisance. It may be fixable by adjusting settings or position. However, it may be that you’d be better off going with an alternative such as a PIR detector instead.

Settings can be adjusted easily on most motion-controlled lights.

3: Lights Not Turning Off

Lights not automatically turning off defeat the whole purpose of using a motion detector in the first place. Instead of saving energy we have now spent additional money on the installation and are actually losing money by the lights staying on.

It can be that the sensor is picking up movement everywhere so never gets a chance to turn off, or it could be that the timer setting needs adjusting to shorten the length of time it stays illuminated.

Some people attempt to solve the problem by putting tape over the sensor, depending on the sensor this can work but isn’t really a long-term solution to the problem.

When installing motion sensors of any kind they should always be installed in conjunction with an override switch. A simple light switch wired in series gives the control to turn the light off, which is great for stormy nights when exterior lights won’t turn off.

4: Lights Not Turning On

If you thought the light not turning off was annoying, having an automatic light that doesn’t turn on is even more of a pain as we are left fumbling around in the dark – I have tripped up in my garden on more than one occasion as my unreliable exterior light fails to detect my presence!

In my scenario, it is my own fault as all my motion sensor needs is a gentle clean to remove the debris that has accumulated around it hampering its performance. The same may be true for your sensor, especially if they are high up and don’t often (or probably never) get maintained.

A simple override switch is a great idea to stop the sensor from triggering the light at night!

5: Activations Due to Pets and Wildlife

My cat is an awesome chap. Despite his grumpy exterior, I know deep, deep down he thinks the world of me. This is why I can look past his tendencies to be most active at night, prowling around the garden looking for a mouse to ‘play’ with.

The downside of his nocturnal activities is that the light outside my bedroom window constantly triggers making it difficult to get a good night’s sleep.

I’ve only got myself to blame as there are two solutions to this problem that I should have got around to sorting months ago.

The first is to use a pet-proof motion sensor. I wrote more about them here, but essentially they are designed to only detect large movement (typically above 80lbs) and not activate on pets and other wildlife.

The second solution is to install a timer on the circuit. I have no real need to have the night on late into the night so a timer would override the motion detector during the early hours preventing the problem. I keep promising myself I’ll get around to doing this.

6: Unreliable Triggering

Microwave sensors are clever pieces of technology that are pretty sensitive to electrical interferences by other signals such as wifi signals.

These can be tough problems to diagnose as the sensor behaves fine one moment and then misbehaves the next.

If it has the functionality, adjusting the frequency of the microwave sensor often solves this problem, or for an easier approach try moving it away from areas where interference may be likely.

7: Not Very Robust

Not being robust is the most polite way I could think of to word it. If I am doing an install where I want more reliability and fewer maintenance issues ill often opt for the cheaper and easier-to-commission PIR detector.

Whilst PIRs don’t have the same level of sensitivity for detections, they are also a bit hardier and less sensitive to knocks.

It’s not unusual for a microwave sensor to go faulty where as a PIR sensor installed at the same time goes on and on. My dad would jump in here and say that the more technologically advanced something is the more likely it is to go wrong.

I must be getting older as I’m starting to see his point of view on things like these.

Dave Nicholas

I have worked as a professional electrician for many years and like to use my experience to help others in any little way I can.

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