A wireless sensor network is a data communication system that consists of from several to thousands of tiny wireless sensor nodes. These battery-powered sensor nodes cooperate with each other to accomplish data transmission. A variety of wireless sensor networks have been developed for different applications in the recent years. In this paper, a data routing protocol, which is designed for a wireless home security network, is proposed. Due to the lifetime of such a network depends entirely on the lifetime of the battery power, the proposed routing protocol chooses hop counts and battery power levels as metrics, in order to conserve as much energy as possible in both computations and data communications. In addition, when some of the nodes fail or run out of battery, the routing protocol could effectively adapt the change and find an alternative path. The robustness and the energy efficiency of the proposed routing protocol were tested, and the results turned out to be successful.