The developers behind popular Kickstarter project Haptix is now back with a product called Touch+. Touch+ is a successor to Haptix and costs just $75. Touch+ is a small and sleek bar that turns any surface into a multitouch controller for your PC or laptop. Touch+ contains two cameras that track the 3D positions of your fingers and allow you to use multitouch by detecting the height of your fingers. It also enables gesture shortcuts by detecting the hand gestures you make. You can use this 3D tracking device to tap, swipe, or zoom on any surface while seeing your fingers on the screen.
You can order the sensor here from Ractiv.