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This work is funded by FEDER, through the Programa Operacional Factores deCompetitividade -COMPETE -and by National funds through FCT -Fundação para a Ciência e Tecnologia -in the frame of -Centro Aos companheiros Gonçalo Costa, Hugo Ramalho e Tiago Leal, que ao meu lado deram incontáveis braçadas (eu mais do que eles!) dentro e fora da piscina, um agradecimento particular. Uma palavra de apreço também para o amigo de infância, Ricardo Pimentel, pelos muitos momentos partilhados ao longo de todo este tempo.Ainda um brinde em honra de quem nestes anos me acompanhou: Carla Guerra, Carolina Francisco, Gabriel Campos, Mariana Sequeira e Susete Neiva. The current work aims to develop a stand-alone pulse oximeter and a photoplethysmographic (PPG) system with measurements of the contact force and height of the finger relatively to the heart. This module, together with other measurements (e.g.electrocardiogram and pulse wave velocity), will be part of a multichannel platform that will be taken to clinical environment.The project comprises the design of hardware for signal conditioning, as well as the development of firmware to implement in a microcontroller unit (the Arduino™). The latter is used to control the system, acquire data and compute , heart rate ( ), contact force and height.Currently, the system is able to retrieve a stable PPG waveform and compute the in real time through the PPG signal peaks and valleys. Signals acquired in a healthy subject lead to a value of . Moreover, the subject arm and forearm orientation is retrieved by the use of accelerometers and used to compute the offset of the finger relatively to the heart. Contact force between the finger and the probe is also measured.
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