The urban environment of the early 21st century contains a large number of consumer devices under private and organizational ownership. Many of these devices contain sensors as well as communication devices. However, most of these sensors are only used for purposes internal to the device. By interconnecting these sensors we can obtain a network which can serve important societal goals. The technological challenges of interconnecting these sensors are relatively minor. The main problem is the human aspect: why would the owners of the sensors offer their readings for public use? In fact, privacy considerations might advise the exact opposite. Such networks will not be accepted unless every owner is motivated to allow the participation of its devices. In this paper we describe an architecture which enables such a system by the formal model of motivational gradients. The original source of motivational gradients are always humans or organizations; however, nodes acting as autonomous agents can negotiate motivational microgradients based on the original macrogradient introduced by humans. We evaluate the networking and computer-human interaction aspects of the proposed architecture.