In this paper, a gateway system between the wireless sensor network (WSN) and TCP/IP is designed for home automation applications. The fundamental components of this system are switches connected to WSN, the gateway between WSN and TCP/IP and a user interface program which can be used to show incoming and outgoing data to the users. The switch units are the end-devices of the WSN. There are WSN and TCP/IP interfaces on the gateway. The gateway behaves like the coordinator of the WSN. Additionally, it enables a communication interface between WSN and the computer via TCP/IP. The WSN used in this work operates based on IEEE 802.15.4 standard. Our experiments show that two way communication between the computer and WSN can be executed in-real time.