Common Types of Proximity Sensors and Their Uses

Proximity sensors are a common element of various modern technological assemblies, and they are able to detect nearby objects without having to make any physical contact. While there are various types of proximity sensors on the market, many operate through the use of emitted electromagnetic fields or electromagnetic radiation to detect objects through field changes or returned signals. In this blog, we will discuss common types of proximity sensors that one may use, ensuring that you find the best fit for your particular needs.

In general, proximity sensors are categorized based on their method of object detection, and there are five main types that one may use. These include inductive, capacitive, ultrasonic, IR, and high-end proximity sensors. Inductive proximity sensors are fully contactless, and they are only suitable for determining when a metallic object is in its presence. To do this, they operate on the law of induction, utilizing an oscillator that drives a coil when a metallic object comes close to contact. There are unshielded and shielded types, the difference being whether the electromagnetic field is unrestricted or concentrated near the front of the assembly. For their applications, such proximity sensors are often found in automation machines and security applications where they serve for the detection of metal objects.

With a capacitive proximity sensor, one can detect both metallic and non-metallic objects like liquids, powders, and granular materials. True to their name, these proximity sensors utilize changes in capacitance to determine the presence of objects. For their makeup, such devices contain an oscillator, Schmitt trigger, and output stitching circle. During operations, the sensor will produce an electrostatic field, and when an object enters the sensing area, two charging plates within the sensor will face a capacitance increase. This in turn causes an oscillator amplitude gain, triggering the sensor output switch. Generally, these sensors are used for moisture control, touch applications, and various industrial applications.

For the ultrasonic proximity sensor, high-frequency ultrasonic signals are relied on for detection. To do this, electrical energy is converted into sonic waves that will bounce off objects when contact is made. These waves will then return to the sensor, and based on the time it took to emit and receive the wave, the proximity of an object can be determined. These sensors can be used for solids, liquids, and granular materials, and they are often used for robotics, fluid detection, UAVs, and more.

With an IR proximity sensor, beams of infrared light are generated and emitted for object detection. As such, these devices are similar in operation to ultrasonic sensors, albeit using IR instead of sonic waves. For their general construction, IR proximity sensors feature IR LEDs and a light detector that captures reflections. With an IR proximity sensor, one can detect materials for distance measurement applications, item counters, security systems, and control applications.

As the final type, many high-end proximity sensors have come about over recent years. These sensors include more unique variations like photoelectric proximity sensors, magnetic proximity sensors, LiDAR proximity sensors, and much more. As each varies in its capabilities and limitations, it can be useful to consider what you need before making a purchasing decision. Once you are ready to begin the procurement process, look no further than ASAP Inventory for all your operational needs.

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September 17, 2021

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