The ACCORDS project aims at solving three issues related to Internet of Things (IoT). The first one consists in developing a software library to ensure interoperability with a set of sensors while putting aside the sensor model to focus on data. The current lack of interoperability restricts the number of sensors that are usable as part of an integrated-sensor platform. Sensors that do not meet the standard protocol ISO/IEEE 11073 (specific to quantified-self devices) are generally excluded from such platforms, despite the small market share of sensors based on standard protocols. Indeed, manufacturers would rather use proprietary protocols like GAFA (Google Apple Facebook Amazon) ones. Thus it underlines the need to communicate with all sensors, no matter which standard or proprietary protocol they use, in order to cover the whole on-market sensors categories. The second challenge is to measure sensors accuracy since most of them are not certified as medical devices. An experiment will be conducted on the best-selling sensors in order to assess their reliability and to compare their measures with standard ones. Studies on health sensors are usually based on the use of medical devices, so as to avoid dealing with potentially inaccurate data. The work carried out for the mainstream market is showing that, considering the example of connected wrists, the measure reliability is decreasing during moderated to high intensity exercises compared to the test at rest, or in case of varied and/or amplified body motion (walking, running, biking), and results are also user dependent (depending on the skin thickness, or motion pattern). Now, even if for some connected wrists, the measure of the number of steps seems quite reliable, the deducted crossed distance may be erroneous. As far as it is possible, to estimate the sensors' reliability experiments will be conducted to evaluate and compare the reliability of the most common sensors to gold-standards. This approach is responding to the increasing demand of consumers to get some guarantee on the results quality regarding the continuous development of more or less reliable wearable technologies. Thirdly, we will analyze health data interactions in a multimodal context for a better health follow-up, especially for the elderly. The final idea is to build, thanks to these three axes, a cloud where all data would be available, in association with their context, to the new health systems builders, namely states, regions, departments, cities, public or freelance establishments, software publisher, mutual insurances, allowing them to work at infinitesimal costs and avoiding current systems limitations. This cloud would be managed by a trusted third-party whose neutrality will enable each individual to register his own personal health data and to decide to share them or not, in whole or in part, temporarily or definitely, the user being at the heart of the decision-making process. This new regulatory paradigm with finally clarify the different sector operators roles: users, health professionals, industrials and insurance companies. Insuring readability, reliability, and security of multimodal data gathered in the user daily living space allows to support the development of health assisted self-management, which raises clinical, economic, and ethical issues, related to public health actions.