This work, as all the others in this section, is part of an effort to implement a large-scale distributed cooperative network in the Douro Demarcated Region in Northeast Portugal, a region in which the effort makes particular sense due to the extremely variable topography and mesoclimates. The system described in this paper is based on tags that are placed in the field and which can be decoded by mobile devices such as mobile phones or PDAs. The tags are used to automatically associate a field location to the relevant database tables or records and also to access contextual information or services. By pointing a mobile device to a tag, the viticulturalist is able to download data such as climatic data or upload information such as disease and pest incidence, without having to provide coordinates or any other references, and without having to return to a central office. The possibility of exchanging contextualized information and accessing contextualized services in the field, using well-known devices such as cell phones, may contribute to increase the rate of adoption of information technology in viticulture, and contribute to more efficient and closer-to-the-crops practices.

This paper analyses solar radiation, wind and water flow as energy sources that can be explored to meet the energy needs of a wireless sensor network router within the context of precision agriculture. It also describes a multi-powered platform solution for wireless devices. The prototype can manage simultaneously the three energy sources and is capable of permanent operation. The energy scavenging techniques double up as sensors, yielding data on the amount of solar radiation, water flow and wind speed, avoiding the need for specific sensors.

This paper is part of a long-term effort to introduce precision viticulture in the Douro region. It presents the architecture, hardware and software of a platform designed for that purpose. Its power-management subsystem is able to recharge batteries with energy harvested from the surrounding environment from up to three sources. It allows the system to sustain operation as a general-purpose wireless acquisition device for remote sensing in large coverage areas, where the power to run the devices is always a concern. The system node, as a ZigBeeTM network element, provides a mesh-type array of acquisition devices ready for deployment in vineyards. In addition to describing the overall architecture, hardware and software of the monitoring system, the paper also reports on the performance of the module in the field, emphasising the energy issues, crucial to obtain self-sustained operation, as well as testing. The platform is currently being used as a simple and compact yet powerful building block for generic remote sensing applications and is well suited to precision viticulture in the Douro region. It is planned to be used as a network of wireless sensors on the canopy of vines, to assist in the development of grapevine powdery mildew prediction models.