Based on a Microchip MGC3130, the 3D Gesture & Tracking Shield brings gesture and motion tracking to the Raspberry Pi at a reasonable price. The Shield supports touch gestures and emits a short-range magnetic field to allow it to recognise gestures performed nearby it too. The 3D Gesture & Tracking Shield communicates with a Raspberry Pi via I2C and is available to purchase worldwide from Seeedstudio for US$12.90.
https://www.notebookcheck.net/Give-your-Raspberry-Pi-some-motion-for-just-US-12-90-with-a-3D-Gesture-Tracking-Shield.426815.0.html