International Conference on Solid State Devices and Materials

Fundamental treatments for quadriplegia due to cervical spinal cord injuries have not yet been estab-lished. Patients currently operate various devices through computers by detecting voice, eye, and tongue movements with sensors; however, there are many challenges regarding the size and performance of these sensors. We have developed a computer interface using an intraoral Photoplethysmography (PPG) sensor that operates devices by measuring and classifying the PPG of the tongue. This sensor measures the position and deformation of the tongue within the oral cavity by illuminating the tongue with light and measuring the reflected light with a Photodiode (PD). In this study, we conducted intraoral PPG measurement using a photo-reflector, classification using reservoir computing, and design and evaluation of circuits for use in the in-traoral PPG sensor.