The automation industry has grown tremendously over the years. Many of the automated processes depend on object detection. From garage gates that open when a car approaches to escalators that start moving when a person stands on the first step, automation is everywhere.
Many machines need a trigger when an object reaches a specific point. In industrial processes, detecting whether the object has reached a specific point becomes a vital task. Security processes also have the need to detect hidden suspicious objects. Many different sensing technologies are available and used in various applications. In this article, we will see six different types of sensors that are popular for object detection.
Inductive proximity sensors can only be used to detect metallic objects. The sensor has its own electromagnetic field which gets disrupted when a metal object comes near it. This disruption indicates the presence of an object. The object can be detected even if it is inside another non-metallic substance. Though direct contact of the object with the sensor is not required, these sensors offer limited sensing ranges. These cost-effective sensors come in different shapes and sizes and are widely used in different automation applications.
Capacitive sensors can detect objects that have a dielectric constant that is different from air. Hence, these sensors can detect objects made from a wide variety of materials such as plastic, paper, wood, etc. They detect a change in the electrostatic field when an object is in the sensing range. The sensing range is quite limited. These sensors also cannot measure the distance of the object from the sensor.
Ultrasonic sensors use sound waves to detect objects. The working involves a short ultrasonic sound wave being transmitted towards the target. The target reflects back the wave which confirms the presence of the object. These sensors can measure the distance of the object from the sensor. Since the working involves sound waves, colour and transparency of the objects have no impact on their detection. The sensors are used widely in places where the level of a liquid needs to be measured or monitored.
The basic working principle of a photoelectric sensor involves transmitting a beam of light and detecting the object based on the reflected light. The sensors are capable of detecting different colours, luminescence, and contrast. Photoelectric sensors that use laser beams are capable of having sensing ranges of more than 50 metres. The commonly used types of photoelectric sensing modes are diffused mode, reflective mode, and through-beam.
Bulgin's slim line photoelectric sensor range provides a cost-effective and flexible solution, with high levels of mechanical and electrical stability.
A simple and secure design enables a watertight and dustproof seal to any standard M5 interface. The sensors are made with a robust Stainless Steel 316 case, sealed to IP67, making them well-suited to manufacturing and industrial automation operations.
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