One of our goals in designing the system is to develop a communicationmechanism that satisfies the requirements ofapplication in the greenhouse. Generally, we have to considerboth a medium access control (MAC) protocol and a routing protocol in designing a communication protocol for the
WSN. In accordance with the environment monitoring requirements of multiple large-scale greenhouses, we designed and implemented a battery-less WSN. In this system, for the MAC layer, we conducted our design based on the FreescaleTM open protocol stack simple medium access control (SMAC; FreescaleTM, 2005b). The physical layer used in the SMAC protocol is based on the IEEE802.15.4 standard, and the MAC layer implementation has been simplified. For the routing protocol, although several sensor network protocols have been proposed, we designed a simple cluster-based protocol in which the node is not equipped with energy detection or geography location devices.