The WearPhone: Changing smartphones into multichannel vital signs monitors

Traditional healthcare solutions oblige patients to stay in hospital; bio-signal monitoring and treatment dosing require the presence of specialized personnel. In turn, this scenario implies high-cost, especially for chronic diseases or fragile people surveillance. Wearable sensor-based healthcare solutions may be an effective approach for lowering costs, since they offer good performance and can be used directly at home, e.g., for permanent self-monitoring. In addition, their communication capabilities make easier to exchange information with remotely located professionals. Wearables are smart objects, consisting of sensors, processing units and communication modules, which rely on a smartphone for data collection, display and remote communication. In this paper, authors modify this paradigm moving the computational capability out of the wearable into the smartphone; in this way, raw vital signal stream can be obtained, overcoming possible limitations of the wearable itself. The aim of the work is to verify multichannel capability of the proposed approach, which paves the way to multi-parametric bio-signal analysis. An experimental setup has been arranged using a real-world smartphone and tests have been carried out to evaluate the performance. In particular, it has been verified that three ECG-like signals can be simultaneously collected leveraging on simple multiplexing in the frequency domain.