Amazon's special feature for its own smartphone won't be a fingerprint sensor or a heart rate monitor, though. Instead, the company's reportedly betting on the use of five cameras embedded into the front of its smartphone's screen to create a glasses-free 3D (think Nintendo 3DS screen, but better) user interface that tracks your eyes and head movements. The amount of cameras employed would be unprecedented for a smartphone. Most smartphones only have one front-facing camera for video chatting and *shudder*selfies*shudder*.
Of the five front-facing cameras, four of them will reportedly be infrared cameras that work with sensors to create the 3D user interface, and the fifth for video chat/Amazon Mayday technical support.