(setup on the door as example)
The InPhase system is an ambient indicator that will notify two remote users when, for example, they are both opening doors, windows, or curtains; watching the same TV channel; sitting on a sofa; or in the kitchen at the same time. Depending on the frequency of coincidences, the level of activity in the receiver varies. Therefore, changing the sound of the chime depends on the frequency of coincidences for certain groups of actions. Likewise, it is possible to use lights or actuators (instead of sounds) to notify the receiving party.
Source: Tsujita, H., Tsukada, K., and Siio, I. 2010. InPhase. In Proceedings of the 27th International Conference Extended Abstracts on Human Factors in Computing Systems (CHI EA’09). ACM Press, 3401–2406.
http://tsujita.org/projects/inphase/
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