The Hello.Wall is a "large ambient display that emits information via light patterns." It is basically a wall with a matrix if LED lights controlled by a computer. The light patterns (can) reflect the state of various "atmospherical" parameters like the level of activity of people, movement and sounds, etc.

The system can be used in conjunction with a special mobile device-the ViewPort-that allows users to decode the visual codes presented by the wall, to download information from the wall or to "paint" signs on the wall by activating the LED lights individually.

The system distinguishes three proximity zones for interaction with the wall: ambient zone (the farthest), notification zone and cell interaction zone (the closest). Ambient zone corresponds to the area outside of the sensors range. In this zone, the wall displays general information (independent of the presence of a particular person). The notification zone corresponds to an intermediate area that detects people passing by. In this zone the wall displays person-specific patterns. Users can then receive more information by using their ViewPort devices. The cell interaction zone corresponds to the range of the individual cell's sensor. By bringing the ViewPort device near a LED light (cell), the user enters the cell interaction zone and is able to control the light of the cell.

The Hello.Wall system has not been formally evaluated. It has only been deployed and presented as a prototype system so there are no conclusions as to how people would accept and use this kind of systems.

Streitz, N., Prante, T., Röcker, C., Alphen, D. V., Magerkurth, C., Stenzel, R., and Plewe, D. (2003). Ambient displays and mobile devices for the creation of social architectural spaces: Supporting informal communication and social awareness in organizations. In O'Hara, K., Perry, M., Churchill, E., and Russell, D., editors, Public and Situated Displays: Social and Interactional Aspects of Shared Display Technologies, chapter 16, pages 387-409. Kluwer Publishers.