An ultrasonic sensor triggers the alarm if a change in air pressure or movement is detected in the cabin of the vehicle. It does this by transmitting ultrasonic sound waves (like a bat’s sonar) around the interior of the vehicle.
It is our favourite sensor for protecting the cabin of the vehicle and is a great upgrade if you carry goods or have a large car.
An ultrasonic sensor is also recommended for vehicles where the windows can be removed intact as this can allow access without setting off other types of alarm sensors. Most Subaru models (which have frameless windows) and vans come into this category.
It can be added as an optional upgrade to any 12 volt AVS car alarm.
Note: because of how the ultrasonic sensor works do not leave animals or children inside the car with the alarm armed. You must also remember to always make sure all the entry points to the car, including windows and sunroofs are shut because air movement will trigger the sensor.