A real-time Wireless Sensor Network for temperature monitoring

In the past, several approaches have been proposed to employ wireless sensor networks in distributed control environment. The aim is to exploit advantages as mobility and scalability, but their diffusion is limited by reliability and predictability requirements. In particular, event-driven protocols usually adopted in standard solutions (as IEEE802.11 or IEEE802.15.4) are not well suited for industrial applications. In this paper, authors propose an hybrid approach that ensures time deadlines respect by means of a TDMA allocation schema and utilizes CSMA/CA for network management purposes. Experimental prototypes, based on COTS hardware, have been realized to verify the feasibility of this solution. A star network with up to 16 nodes and a cycle time of 128 ms has been implemented in order to monitor the fluid temperature in plastic machineries.