Following up on a reader comment that the iPhone 4S had an “unusual-looking” black component next to its ambient light sensor, iFixit has discovered that the component is actually an infrared proximity sensor. According to the report, the IR sensor is active any time the screen is activated — a major change from past iPhones, which only activated the proximity sensor when a call was initiated. iFixit suggests that the increased activity of the proximity sensor on the iPhone 4S may be due to Siri’s “Raise to Speak” feature, which would require such a feature active to know when the user has raised the phone to their head to speak.
Charles Starrett was a senior editor at iLounge. He's been covering the iPod, iPhone, and iPad since their inception. He has written numerous articles and reviews, and his work has been featured in multiple publications.