This MSc thesis provides a simple solution to merge sensor networks of dierent manufacturers. The system uses an inexpensive, wireless router to collect data of the subnetworks. My solution provides a TWI bus to connect these subnetworks (the router is connected via a microcontroller). The connected devices are using a transport protocol to unify their specic message formats. The system is based on several technologies. The application is running on the newest version of a GNU/Linux distribution, called OpenWrt. The router's connection to the TWI bus is provided by an Arduino-compatible board. The data processing layer implemented in the Ruby programming language and the web interface is based on the Sinatra framework. The collected sensor data is handled by rrdtools. The system easily can be extended by plug-ins. Plug-ins could be implemented using JSON files and Ruby scripts. The thesis introduces the existing solutions and describes the planning and implementation process of this framework.