Smartphones become popular. They have various sensors in order to bring many functions to users. They employ a mobile operating system for the control of sensors. In this situation, a large amount of data comes to the operating system from sensors. While such data is important for effective operations of smartphones, it is not well known that how it affects the operating system performance. This paper describes an evaluation environment that mimics a smartphone. We selected the Android as an operating system and the Pandaboard-ES as a target board. The Pandaboard-ES equips a Bluetooth module, and the Wii Remote is used to operate the board via Bluetooth. We perform benchmark tests to evaluate sensor effects to the operating system, and the result shows that sensors have a harmful effect to the performance.