We're entering the era of 'ambient intelligence', in which everyday objects broadcast data about themselves and their environment.
As you approach a traffic blackspot, sensors in your car will detect it and reduce the speed. And GPS co-ordinates of places regarded as unsafe to walk at night will be broadcast to mobile devices.
In Japan, location-based services from GeoVector let the Mapions Pointing Application deliver information on businesses inside a building to a GPS-enabled cameraphone. In the UK, handsets with the technology should hit the market by the end of 2008.
In homes, floor sensors will detect empty rooms and automatically lower the thermostat and turn off lights. Agilewaves, a firm founded by ex-Nasa scientists, is working with builders to install sensors on switches, pipes and gas valves. Eventually they hope to offer neighbourhoods, subdivisions or municipalities a big-picture view of their carbon footprint.
Future homes will have "a dashboard that gives real-time performance feedback", says Peter Sharer, CEO of Agilewaves. "Homes that have this instrumentation are likely to hook into their neighbours' homes. In 10 or 15 years, entire communities will be networked."
The most significant use of sensors in homes, however, will be to monitor inhabitants' health. In the US, the government has approved an under-the-mattress monitor that activates when patients with heart problems lie down. And Japan's Matsushita has built a toilet seat that sends tiny electric charges through a user's buttocks to measure body fat.