What are Proximity Sensors
As the sensor name suggest, Proximity sensor is a sensor which can detect other object, which comes closer to it, up to a certain range of distance without any physical connection. The covering distance of sensor is called sensing range which varies according to size of sensor, for example an 18 mm diameter inductive sensor will have sensing range for 5 mm to 8 mm. See datasheet here so you can get idea that what is proximity sensor.
The maximum distance at which sensor can sense other object is called nominal range, which is also depend on size of sensors. There are some sensors for which you can adjust their sensing and nominal ranges. You can see here how adjustable proximity sensor works. Proximity sensor are highly reliable and long functional life because of no mechanical parts and no physical contact between sensor and sensed object.
How it works
Proximity sensor emits electromagnetic field or a ray of electromagnetic radiations, infrared, for instance, and wait for changes in these radiations or bounce back signal. The object which is sensed by proximity sensor is often called sensor’s target object. The target demand for different proximity sensors is different. For example , a capacitive proximity sensor or photoelectric sensor often demands for plastic target which is more suitable for them and an inductive proximity sensor always want a metal object as sensor’s target.
Proximity sensor types
There are different types of proximity sensors but mainly are two by which they known.
- Inductive type
- Capacitive type
Inductive type can detect metal objects and capacitive type can detect any object which come closer to them. If you want to check other types you can view by this link.
Proximity sensor uses
Proximity sensors have huge applications across every technological field. They finds application in industrial and manufacturing areas. They sense material and then response some type of action or simply tell about presence or absence of that material. The most important feature of these sensor is that they don’t require physical connection with their target which is being sensed. That is why they are often called non-contact sensors.
Every type of sensor has its own technique of use for a specific operation in any device. Here I will tell you about the applications of proximity sensors in android and IOS.
what is proximity sensor in mobile
I hope now you are known by this fact that proximity sensor works when anything come close to it. Here i will tell you about working of proximity sensor in mobile.
Large touch screen displays use huge battery power. So it should be turned off while you its not in use like calling someone or when the phone is in pocket. In that case proximity sensor turn off your mobile screen, as in both case mobile screen is close to your ear/cheeks or body in pocket. In such cases proximity sensor activate, sense object and send a signal to mobile processor to turn off display.
There are some other methods also, that are used for proximity sensing. For example, detecting the change in capacitance, inductance, magnetic field or even techniques like sonar. But, I doubt if they are used in mobiles. Thank you for your reading.
Please feel free to ask me anything about it.