Ultrasonic sensors for monitoring barriers

SNT Sensortechnik AG: Entrance and exit barriers are usually monitored using induction loops in the ground. While a car is on the loop, it switches and keeps the gate open. Smaller or non-metallic objects (bicycles or people) are not detected. This can lead to accidents, for instance when a bike runs directly behind the car and the barrier is lowered already.

The solution shown here uses an ultrasonic sensor mounted approximately at half height of the barrier and aligned parallel to the barrier. The sensor switches as long as the gate is open and an object is detected. The controller keeps the barrier open until there is nothing in their area. Thus the additional ultrasonic sensor extends under certain circumstances the opening time of the barrier.

The advantage of using an ultrasonic sensor is its function as scanner type sensor. It does not require a reflector or a receiver on the other side of the road. It is sufficient if the ultrasonic signal is reflected from an object.

SNT Sensortechnik AG is a specialist in ultrasonic sensors for more than 20 years.