All right! Siri is in news once again. This time for a proximity sensor.
iFixtit had recently carried out a teardown of iPhone 4S and found a component that could not identified immediately.
It was determined later that the component is a Light Emitting Diode(LED). This LED acts as a secondary proximity sensor.
The functions of LED appear to be tied directly to Siri. Earlier models of iPhone have had proximity sensor that was designed to shut your handset’s touchscreen off when you raised it to your ear. This was designed to prevent your face from dialing numbers when you are attending or making a phone call. Normally sensor is active only either during a phone call or when you are using some Voice-Over Internet Protocol (VOIP) app like Skype.
However, new infrared LED is constantly if you have “Raise to speak” enabled. It is likely drawing diminutive amount of power from the battery of iPhone 4S. This can also be a cause of the rapid draining of iPhone 4S battery.
While using the phone, iPhone 4S would emit the infrared-beam towards you but you do not need to worry as that beam is harmless.