Internet of Things (IoT) has been widely researched over the past decade. Recently, many research results of IoT related to emergency system, smart building and medical system, etc. The key for IoT applications are the ability to interact with physical world through computation, communication, and machine control. However, each sensor device in IoT cannot conveniently communicate with other terminal devices through internet protocol. So, it is necessary to establish protocol translation stack or equipment between two WSN groups. That is very inefficient and high overhead cost of network construction. The development of micro-IP (uIP) solves this problem. The uIP reduce cost of protocol translation and it also realizes the machine to machine (M2M) concept in wireless sensor network. Therefore, this paper proposes a solution for porting uIP library to the wireless sensor network devices and presents the integration of a speaker module and IPv6 ready sensor device. We also propose a safe building application based on the integrated system to help people escaping from disaster environment. In conclusion, our contributions are building an IPv6 ready wireless sensor network environment and develop a safe building system to make the concept of IoT in IPv6 network environment come true.