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How To Set Off a Car Alarm With a Laser Pointer?

How To Set Off a Car Alarm With a Laser Pointer?

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In its simplest form, a car alarm is a collection of sensors connected to a siren.

A simple alarm may have a switch on the driver’s door.

If someone opened or attempted to open the door, the siren would start wailing.

In the same way, there can be several sensors and security features installed in a car that can prevent it from getting stolen.

Some of the most common security features installed in cars today are:

  1. Transmitter alarms
  2. Door sensors
  3. Alarm alerts
  4. Pressure and window sensors
  5. Tilt and motion sensors

However, since cars are so well protected, sometimes other objects can trigger a car’s alarm, too.

But is a laser pointer one of them?

If you’re wondering how to set off a car alarm with a laser pointer, you’ve come to the right place. 

Can a Laser Pointer Set Off a Car Alarm?


We first need to understand how a car alarm works.

As we mentioned above, there are several sensors in a well-protected car.

The one sensor that can trigger because of a laser is a motion sensor, given you’re using the right laser to do it.

car auto alarm system

The ultrasonic sensors on your vehicle use a more complex version of sonar.

They emit sound waves that bounce off objects near your car.

This ricochet of waves tells your car how far or near an object is.

If an object is too close, your car gets alerted.

Every alarm system has its way of alerting the driver.

It could be a series of beeps or a digital display inside the car. 

Some car alarm systems also have perimeter scanners that monitor what’s happening around your car.

The most common perimeter scanner you’ll see on cars is radar. It has a receiver and a transmitter.

The transmitter sends out signals, and the receiver deciphers the signals that come back. 

So, all in all, if your car has an advanced motion detecting system and an IR laser, you can trigger your car’s alarm. 

How to Set Off a Car Alarm with a Laser Pointer?

a laser pointer in a hand

A motion sensor works a lot like an ultrasonic sensor.

An active motion sensor emits different signal frequencies, while passive motion sensors can detect infrared signals.

If the motion sensor senses infrared energy nearby, the alarm can be triggered.

In the same way, if you used a low-powered IR laser and aimed it exactly at the sensor, you could trigger it.

Another way you can trigger a car’s motion sensor is through a high-powered laser (since the temperature matters in this case).

Lights can also trigger motion detectors that sense infrared radiation.

If the light changes temperature rapidly, the sensor could be activated.  

Is There a Device That Can Set off Car Alarms?

Yes. Using a keychain transmitter, you can activate your car’s alarm remotely.

Almost every car that has a car alarm system is going to come with a keychain transmitter.

With the transmitter, you can lock the doors and disarm the alarm system, and you can also set off your car’s alarm. 

Woman unlocking a car by remote keychain

The sole purpose of a portable transmitter is to give you the ability to control your car’s alarm system when you’re not close to your car.

For instance, if you’re leaving your car in a parking lot while you pick up the groceries, you can arm your car with the press of a button. 

When you come back, you can disarm your vehicle by pressing the same button.

In a few cases, your car’s brain will make it flash the lights, while other cars will sound the horn when the alarm is being turned off.

This can also help notify you if you’re near the car. 

Having the ability to set off the car’s alarm manually has made cars’ alarm systems a lot more useful.

Keychain transmitters also let you unlock your car’s power doors and turn on your car’s lights before you get into your car.

However, before keychain transmitters existed, cars relied on a delay mechanism.

Just like your home security system, you enabled your car’s alarm when you parked the car.

After this, you had only 30 seconds to get out of the car, grab your stuff, and lock your doors.

If you were unlocking your car, you had the same time to turn off the alarm. 

This system was incredibly problematic.

Not only did it give thieves a 30-second window to break into your car and disable its alarm system, but 30 seconds, in some cases, isn’t enough time to exit the vehicle with all of your belongings. 

Some systems, however, can give you even more control over the car.

These devices have a built-in pager mechanism and a computer.

If an intruder meddles with your car, the pager can tell the owner which car sensors were triggered.

However, a car alarm can also go off when an intruder isn’t meddling with your car.

The reasons for this can be:

  • Extra sensitive sensors
  • A low or dead battery
  • Erroneous installation of a car alarm
  • Corroded battery terminals 
  • Poor connection to control unit
  • A broken lock
  • A Dirty hood


While there is a way a laser can trigger a car’s alarm, it solely depends on the kinds of sensors installed in the car and the type of laser pointer one is using.

Nowadays, car security has improved greatly; however, there is still a way to go before it is perfected. 

To ensure you steer clear of this problem, consider covering your car after you’ve parked it.

The cover can greatly reduce the chances of a laser beam triggering the alarm through your car’s lights, and it can also protect it from unwanted dust.

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