The ICT4Life Open Source framework contains libraries for acquiring and processing data from different sensors, machine learning algorithms for activity recognition, as well as fusion methods of multiple modalities either at an early or at a late stage. The main purpose of the introduced system is to enable an easy customization of patients' monitoring using different types of sensors. Furthermore, by allowing an easy integration of new sensors or types of activities, the proposed subsystem supports the development of new solutions for different diseases, than the ones considered in the ICT4Life p roject.