The New Scientist reports on NRC Tampere's whimsical experiment to create a touch screen on a wall of ice:
"This was a playful experiment, but one that we think showed interactive computing interfaces can now be built anywhere," says Jyri Huopaniemi at Nokia's research lab in Tampere, whose team built the touchscreen, dubbed Ubice, or ubiquitous ice.
Finland has a tradition of building snow and ice sculptures during its long winter. It was these that inspired the device, says Antti Virolainen, a member of the Nokia team. "We decided to see if we could make an ice sculpture that was interactive."
The team commissioned a firm in nearby Oulu to retrieve a tonne of 25-centimetre-thick river ice, and used a chainsaw to cut it into 50-centimetre-square slabs. They used these to make a 2-metre by 1.5-metre ice wall and then blasted the surface with a heat gun - more typically used for stripping paint - to create a smooth surface.
A near-infrared light source mounted behind the "screen" bathes it in invisible light, and an array of near-infrared cameras, also behind the wall, are focused on the front surface. A hand placed on the ice reflects the light towards the camera array and the signal each camera receives helps a nearby PC establish the hand's position, size and motion. The PC is also connected to a projector, which uses the data to project imagery - such as flames - beneath the user's hand.