A device which detects the presence of an object when it is within a stipulated range and passes a signal is known as a proximity sensor. These sensors were used in cars to avoid accidents, near to the exit and entrance doors and other places. Today these sensing devices are used in mobile phones too. These electronic devices send a signal to the circuit to perform simple actions such as opening a door, switching on a light, switching on the mobile and so forth.
Majority of these electrical circuits are designed to detect things that come in close proximity to object. However, there are devices which are designed specifically to detect particular objects only.
There are both active and passive proximity sensors which differ according to its features. The active sensors search for an object actively and send signals constantly. It then waits for the signal to reflect back. The time between sending the signal and obtaining a reflection is calculated to determine the distance of the object which is near-by. Active sensors are used on automatic doors which open when the person approaches it. The sensors on these doors send beams of infrared rays which fall on the person walking upto the door. It is then reflected back to the senor that signals the door to open.
The passive sensors function on the basis of the information derived from the environment. A signal is sent to the electrical circuit when the change occurs. Infrared light is emitted by every object but the frequency varies according to the type of object which it intercepts. A perfect example of passive sensors is the outdoor safety lights which turn on when it senses the frequency of a human body.
Most of the modern mobiles are equipped with sensors to avoid people to interact with the screen while they are on a phone call. The sensor switches off the screen when it detects an object in front of it. The sensors are activated when the screen is covered with an opaque object. The screen is activated again when the object is moved or when the sensor is no longer blocked.
iPhone 4 Proximity Sensor Issue:
The latest iPhone 4 has several issues with its super-sensitive sensors which include muted calls, hanging up in the midst of a conversation and unintentionally dialing numbers.
There are a few solutions which can be adopted to solve this issue with the new iPhone 4.
Resetting the network setting is one of the most effective solutions to the problem. All the network settings such as VPN, passwords and APN settings are automatically reset.
Resetting all the settings in the phone is another solution through which all the preferences are reset without deleting media or data.
Restarting the iPhone 4 is another solution to this issue. Slide the power off and then switch on the device again. The iPhone 4 sensor issue can be solved easily through the new iPhone software updates.