Abstract
We propose a concept of Open Sensor Networks that are constructed from Open Source Hardware, Open Source Software, Web Service, and Cloud Computing. In this paper, Open Source Hardware is hardware that is easily available at individual level. Therefore, developers without knowledge of the hardware can join and contribute to the sensor network developer groups. Furthermore, Open Sensor Networks provide the sensor information to developers as a web service. This paper introduces about the prototype RT sensor box and web system that we developed.