The University of Tokyo has demonstrated at Siggraph an interesting haptics system where you can feel contact .. without any contact !

From the paper :

“Airborne Ultrasound Tactile Display [Iwamoto et al. 2008]” is a tactile display which provides tactile sensation onto the user’s hand. It utilizes the nonlinear phenomenon of ultrasound; acoustic radiation pressure. When an object interrupts the propagation of ultrasound, a pressure field is exerted on the surface of the object. (…)

The current version of prototype consists of 324 ultrasound transducers. The resonant frequency is 40 kHz. The phase delays and amplitudes of all the transducers are controlled individually to generate one focal point and move it three-dimensionally. The total output force within the focal region is 1.6 gf. The diameter of the focal point is 20 mm. The prototype produce sufficient vibrations up to 1 kHz.”

The range is not specified and all the other numbers are quite meaningless for me =)

This is a really interesting system! I’m wondering if this could be extended to simulate touch on any body part ? This is a step beyond the 3rd Space Vest, with its 8 impact points.

Honorable mention to the low cost hand tracking system :

While camera-based and marker-less hand tracking systems are demonstrated these days, we use Wiimote (Nintendo) which has an infrared (IR) camera for simplicity. A retroreflective marker is attached on the tip of user’s middle finger. IR LEDs illuminate the marker and two Wiimotes sense the 3D position of the finger. Owing to this hand-tracking system, the users can handle the floating virtual image with their hands.