This vision of the near future is summarised under the term Ambient Intelligence. It means the convergence of ubiquitous computing, ubiquitous communication, and interfaces adapting to the user. Humans will be surrounded all the time wherever they are by unobtrusive, interconnected intelligent objects. Furniture, vehicles, clothes, roads, even paint will be equipped with Ambient Intelligence.

The term Ambient Intelligence was coined in 1999 by the Advisory Group to the European Community's Information Society Technology Programme (ISTAG). Two years later, in February 2001, ISTAG published 'Scenarios for Ambient Intelligence in 2010', which show concrete visions how life in tomorrow's user-friendly information society could be like. In ISTAG's world we meet Maria, who travels to the Far East with great ease: self-arranged visa, automated ID check without queuing, a rental car waiting to be driven to the hotel without key, and a hotel room, which adapts automatically to her favoured room temperature and music choice.

In another scenario we see Dimitrios, whose alter ego 'Digital Me', embedded in his clothes, handles his communication intelligently by selecting the appropriate action for each call. Scenario 3 shows the perfect day of Carmen, who can smoothly drive around the city and gets the ingredients for her cake thanks to an intelligent traffic system and her e-fridge. Scenario 4 lets us join the social learning experience of Annette and Solomon in the Ambient, where they meet fellow learners a thousand miles away, give 3-D presentations to the others, and get their individual homework from the Ambient.

The ISTAG scenarios imply a bunch of social, economic and technological challenges. The basic question is: Would people like to have Ambient Intelligence around them? Social acceptance will depend on many factors. Ambient Intelligence can only succeed, if it makes everyday life easier, offers additional opportunities for personal expression and facilitates human interaction. However, this is not enough.

You do not necessarily have to be paranoid for getting a little bit uneasy, if you think of all the interconnected smart things that surround you in your future e-home having a combined IQ far above yours. In a way, it is quite a relief to know that all things in your home, including your PC and your heating system, are dumb. They give you the feeling that you are always in control. This feeling is in danger, if fridges, toasters, lamps, and wall paint suddenly turn smart. The very advantage of Ambient Intelligence could become paradoxically reverted: Devices and applications, which have become physically unobtrusive, could turn out to be psychologically obtrusive. The bottom-line: Ambient Intelligence has to be controllable – even by people who have not graduated 'Summa cum laude' in computer science.

The technological challenges are at least as demanding as the social aspects. Unobtrusive hardware requires a major step further in miniaturisation. This involves molecular processing, new power solutions, like micro-power usage and self-generating power, and seamless interfaces, which invisibly enable users to interact with their intelligent environment. As there are billions of ambient-intelligent devices required for making the technological environment in just one city smart, the production cost for an ambient-intelligent device has to decrease to a few cents to make Ambient Intelligence economically feasible.

Ambient Intelligence puts also high demands on networks that let current 3G networks appear as a communications system from the stone age. Fred Boekhorst, senior vice president of research at Philips, in February presented a concrete idea of what the bandwidth requirements will be like: "There will be the need to interface large HDTV displays with data rates as high as 5 Gb/s." Ambient intelligence, he added, will require sub-systems that span 9 orders of magnitude in bandwidth. Intuitive music retrieval – you hum a song, and your ambient intelligent HiFi system finds and plays it – requires an estimated computing power of 3 giga-ops, 300 billion operations per second, to search a database of 20,000 songs with a half-second response time, Mr Boekhorst explained. 3D television or even 3D real-time holographic videoconferencing would certainly need a lot more computing power.

To cope with such an enormous traffic load in a seamless way, fully converged core and broadband networks are needed, which require a highly sophisticated dynamic network management and advances in middleware and agent technology.

To make the interface intuitive and adapted to human behaviour, advanced technologies for pattern recognition, including both speech and gestures, will be needed. Above all, Ambient Intelligence systems have to be safe, robust, and secure. Trust technologies are essential to make users accept ambient-intelligent environments.

For the time being you can still talk and hum to the walls of your home without causing action by some smart devices. However, you should better start getting accustomed to the thought that in some years, when you cry out "Oh, Lord!" your HiFi system could start playing spiritual tunes.