Flexible piezoelectric sensor for podiatric applications with wireless communication

For reasons of availability and cost, patients are sent home earlier and earlier, with limited follow-up due to the complexity and size of medical devices. In this context, researchers from IETR and MIPS laboratories are working on a device which should monitor the progress of a patient, in order to detect early the aggravation of a disease such as Chronic Obstructive Pulmonary Disease (COPD) or diabetes with walking disorders. The device is based on flexible piezoelectric thin films (3 µm thick) that can be used as podiatric sensors and have been developed by the IETR laboratory. The originality of this work resides both in the approach to the design of the gait monitoring device, because carried out directly in consultation with a doctor from the University Hospital of Nantes and a podiatrist, and in the portability of the device that should eventually allow the follow-up of a patient at home. For this study, the flexible piezoelectric sensors have been elaborated using a Chemical Solution Deposition (CSD) process and a commercial aluminum (Al) foil as substrate. In order to increase the flexibility of sensors and to aid its insertion in a shoe, piezoelectric films have been encapsulated by lamination into polyethylene terephthalate (PET, 150 μm). In this paper, elaboration and characterizations of flexible piezoelectric sensors, analog to digital converter and wireless communication protocol used for data transmission, are presented.