The vision of ambient intelligence opens a world of unprecedented experiences: the interaction of people with electronic devices is changed as contextual awareness, natural interfaces and ubiquitous availability of information are realized. We analyze the consequences of the ambient intelligence vision for electronic devices by mapping the involved technologies on a power-information graph. Based on the differences in power consumption, three types of devices are introduced: the autonomous or microWatt-node, the personal or milliWatt-node and the static or Watt-node. Ambient intelligent functions are realized by a network of these devices with the computing, communication and interface electronics realized in silicon IC technologies. Three case studies highlight the IC design challenges involved, and show the variety of problems that have to be solved.