What do you do when Apple keeps on taking away buttons from their devices (and when swipe gestures from nearly all edges are already taken by something else)? Well, you invent a new button:
So when we ran out of buttons to hide our software’s UI behind, it really forced us to use our imagination. Instead of squeezing UI in where it didn’t fit, we built a new button to conceal it: it’s called the Camera Button.
The Camera Button basically transforms your iDevice’s camera lens into an ambient light sensor:
The Camera Button works by detecting the amount of light coming in through the camera. Covering up the camera with your finger blocks all light, triggering a response from the iPad. The tricky part was getting it to work in all lighting conditions, across all iPad cameras.