Turn the back of your phone into a touchpad

Smartphones use large touchscreens on the front as a useful touchscreen interface. However, our hands also naturally wrap around the back of the phone. This area is underused as an interface, but the BackTrack designers found a way to change that.

The keys on the 2D rear matrix are translated into a pair of keys on the linear row of pads on the screen before. This can then be rebuilt into the touch slot on the rear touchpad.

The idea is simple. The project video notes that the conductive tape can be placed on a multi-touch screen, allowing keys to be read remotely. Taking this concept further, BackTrack works by creating a 2D matrix on the back of the phone and connecting that matrix to a series of pads in a row on the front touchscreen. Then the keys on the rear touchpad can be read by the existing touchscreen on the front display.

In practice, this requires the use of sophisticated transparent electrodes and flexible connections. However, the team behind Backtrack was able to create its passive rear touchpad in a form factor that fits into a simple phone case. It can then be used to play games or otherwise interface with the phone.

We expect phone manufacturers to start creating interfaces that use the back surface of the phone. Apple has already explored this with the rarely discussed back-tapping feature. The implementation of a full 2D touchpad on the rear could quickly become a big point of difference for the first handset maker to get it right. Video after the break.

[Thanks to Itay for the tip!]