The Air Pencil from Adtile lets anyone capture freeform movement in space using their mobile device. Air Pencil taps into a smartphone’s native micro-electro-mechanical systems (MEMS) — namely the three-axis magnetometer, three-axis accelerometer and three-axis gyroscope. It then calls on sophisticated Adtile-designed algorithms to reliably infer the precise movements of the user based on sensor data.

via adtile.me