A Look at How Proximity Sensors Work


Proximity sensors are detectors that convert the physical quantity into a signal. Powered mostly by infrared filters, there are several types of these available for different uses and they are all deployed in different areas.

Proximity sensors are devices that detect objects that are nearby even when there has not been physical contact between the sensor and the object in question. The detector will send out a signal as long as the object in question is within a particular vicinity. The sensors also function by converting information on the movement or presence of an object into an electrical signal that is known as proximity sensors.

Types of Proximity Sensors

There are different types of proximity sensors. They are used according to the need, the material detection among other things. We take a look at these below:

Inductive Proximity Sensors

Inductive Proximity Sensor

These are sensors that generate an output signal or electrical signals as soon as a metal object comes either inside or near its sensing area from any specific direction. The metal objects that can be detected include iron, aluminum, brass, copper and so on and each of these can be detected at different sensing distances.

With these types of sensors, flat targets are preferable and targets that are larger than the sensing face may increase the sensing distance. We first saw the inductive proximity sensor in the mid 60’s when it got introduced.

Capacitive Proximity Sensors

Capacitive Proximity Sensor

These sensors can detect metals but they can also detect resins, powders, liquids, etc. The way this sensor works can vary accordingly covering material, cable longness, and noise sensitivity. The sensing distance can also vary based on factors like temperature, sensing object, surrounding the object and the mounting distance between the sensors. The maximum range of sensing is 25mm.

Magnetic proximity sensors

Magnetic Proximity Sensor

As the name implies, these types of sensors pick up magnets. They do not have any electrical noise effect and can work in DC or AC and/or both. The sensing distance can also vary as a result of factors like temperature, objects surrounding it, as well the mounting distance between the sensors. This category of sensors has the highest sensing range as they can cover as much as 120mm. These are the kind of sensors used in mobile phones, tablets and security gadgets. On a mobile phone, it greatly improves the functionality of the device, making it responsive and useful.

These are the main types of sensors available today and how they work.



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