The concept consists of a set of two white, round electronic stones which are connected to each other only. Through heat and touch sensors the unit detects if someone holds it in his/her hand. As soon as someone keeps his/her stone, the stone sends a signal to the remote unit, which will then beep. When the counterpart takes the stone in his or her hand, it detects the touch and sends a signal back to the first stone, which will be warmed up by an internal heating device.
Source: Tollmar, K., Junestrand, S., and Torgny, O. 2000. Virtually living together. In Proceedings of the Conference on Designing Interactive Systems Processes, Practices,Methods, and Techniques (DIS’00). ACM Press, 83–91.
http://smart.tii.se/smart/projects/whitestones/index_en.html
http://smart.tii.se/smart_old/smart_eng/emcom-eng.html
