Nokia's interactive icemen

Researchers at Nokia in Finland have created one of the coolest interactive displays around – the world’s first ice touchscreen. Whilst not being marketed as a practical solution, it is another great example of what is known as ‘Ubiquitous Computing’. This is the practice of making use of the general environment to create interfaces and displays.

Speaking to New Scientist magazine, Jyri Huopaniemi from Nokia’s research laboratory said: “This was a playful experiment, but one that we think showed interactive computer interfaces can now be built anywhere.”
He and the rest of the Context-Aware Social Media team built the touchscreen, which they have dubbed Ubice (Ubiquitous Ice), inspired by Finalnd’s tradition of ice sculpture during the winter months.
“We decided to see if we could make an ice sculpture that was interactive.”
The team used a 4 x 3 array of 50cm slabs of ice, 25 cm thick, to create a wall and then blasted its surface with a heat gun to create a smooth surface. Interactivity was added using projection technology, similar to that first used in Microsoft’s Surface application.
A near IR light source mounted behind the ice screen covers the rear surface in invisible light, which is detected by an array of cameras focused on the front surface, but also located on the rear of the wall. 
Anything place on the front of the ice, deflects the light towards the camera array. A connected PC then calculates the size, and position, and any movement or the object. This then outputs content to the projector, allowing effects such as flames to track the movement.