Can Ghosts Set Off Motion Detectors?

Spooked by your motion detector setting off? Well, if there’s no one around, can it be a paranormal existence that triggered your alarm? Hold your horses – let’s quickly take a look at whether ghosts can set off motion detectors or not!

Can Ghosts Set Off Motion Detectors?

Ghosts can’t set off motion detectors.

Since motion sensors pick up heat signals, the object which triggers the alarm should emit some level of infrared radiation. Since paranormal beings don’t give off energy (at least to our limited paranormal knowledge), they can’t set off detectors.

Credits: National Geographic

Motion detectors normally operate by sending out infrared radiations to pick up heat signals. If an object emits heat, the sensor picks it up and triggers an alarm. So, as you can imagine, the trigger is actually dependent on the presence of an energy-emitting object only.

Secondly, a microwave-based sensor might trigger alarms if an object is in proximity of the sensor. But again, it has to be a physical object capable of reflecting back microwaves.

Now, you might be wondering:

But how did my motion detector set off by itself without a human’s presence?

Well, humans aren’t the only source of heat. If you’ve made sure there’s no intrusion, it’s very likely a different heat source triggered the alarm.

With that said, let’s explore a few more sources of heat (other than ghosts!) which can set off motion sensors.

What Can Set Off a Motion Detector?

Motion detectors can be set off by anything which emits a form of infrared radiation or reflects microwaves. Other than humans, the following are the most common causes of a false alarm trigger:

  • Insects – flying or crawling
  • Heaters
  • Fans
  • Pets
  • Physical objects close to the sensor (especially those which move)
  • Malfunction – blown fuse or a battery issue

Though we’ve summed up the most common causes of a triggering motion sensor, this is, by no means, an exhaustive list. Literally any object which is capable of movement and emits some energy is a potential culprit.

The sensitivity of the motion sensor might also be an issue. If it’s fairly sensitive and triggers on the slightest of change, you might want to adjust its settings. However, some motion sensors don’t have an adjustable sensitivity range and operate on the manufacturer’s settings. Tough luck.

Can I Detect Ghosts Some Way?

You can find several paranormal detectors online which pick up EMF emissions from sources. However, these devices are (mostly) inaccurate and pick just about any electromagnetic signal.

But, motion sensors i.e. infrared radiations and microwaves are a total fail against detecting ghosts.

Almost every living object (and a few non-living exceptions) give off electromagnetic waves. Now these detectors might go off in unusual places and prime your mind to call your house “haunted”. But, hold your horses, yet again.

Here’s a user review from one of the most acclaimed ghost detector devices on Amazon:

Here’s another one:

If you aren’t able to tell from the reviews, these devices are, at best, excellent pranks. So, if you’re looking for a way to spook your roommate or friend, these ghost detectors might be the best gag.

FAQs on Ghosts Setting Off Motion Detectors

Still have a few confusions regarding ghosts setting off motion sensors? Read ahead as we answer some confusions you might have related to the article. 

What can set off a motion detector?

PIR motion detectors are set off by heat sources close to the sensor. Similarly, microwave motion detectors are set off by physical objects in the proximity of the sensor. If you use a dual-technology sensor, both these sensors need to be triggered for an alarm.
One of the most common triggers would be a human. Since we actively emit heat (and IR radiations), a motion sensor can easily be triggered. Apart from humans, insects, pets, lighting sources, and swiftly moving objects might also set off a motion detector.

Can a spider set off a motion detector?

Spiders and other insects can set off motion detectors. If the spider crawls directly over the sensor or forms a cobweb, it might fool the sensor into triggering an alarm. Service the sensor frequently such that no spiders or (other) insects are close to the sensor’s emitters. 
If you face frequent false alarms, it’s better if you use something to sway the spiders away. Peppermint sprays and conkers have proven to be excellent spider repellers. Eucalyptus also has the same effect to some degree.
Play around and see which works best for you.

Can a flashlight set off a motion detector? 

Flashlights, generally, don’t set off motion detectors. Since these lights don’t dissipate a large amount of energy or radiation, the sensor doesn’t pick them up. However, a sensitive motion sensor might detect the sudden change in temperature as the light source is turned on. 
A different light source such as a light bulb might trigger the detector. These bulbs can cause a quick change in temperature which is often how a sensor picks up signals. However, if the light source isn’t as intense (such as a flashlight), there’s a relatively less chance of a false alarm.

Concluding our article on whether ghosts can set off motion detectors or not – they really can’t. If you were hoping to find paranormal existence through a motion detector, we’re sorry to break the bad news to you.Though you can still prank a close friend with one of the ghost detectors if you’re looking for a fun gag.