Do you know how your smart phone detect your accidental touchscreen taps when held to the ear during a call ??
During a call when you hold your phone to your ear your phone detect your accidental touchscreen taps and turn the light off . This is done by a sensor named PROXIMITY SENSOR A proximity Sensor can able to detect the presence of nearby objects without any physical contact.
This sensor emits an electromagnetic field of electromagnetic radiation and make changes in the field or return signal. Proximity sensor is suitable for plastic target and an inductive proximity sensor always requires a metal target. Proximity sensor can have long functional life because of the absence of mechanical parts and lack of physical contact between sensor and the sensed object.