Underwater electromyogram sensor for diving

For monitoring the safety of divers, we propose an underwater electromyogram (EMG) sensor that is incorporated into a wetsuit. The sensor has cavities in front of the EMG electrodes. Except for parts of the cavities in contact with human skin, the sensor is covered with chloroprene rubber sponge, which is used to make wetsuits. When using our EMG sensor under water, the cavities of the sensor are filled with liquid, and, by pressing the sensor to the skin, the liquid inside the cavities are physically isolated from the liquid outside the sensor. We fabricated our sensor and conducted EMG-signal measurements in seawater and freshwater. We found that, in the case of seawater, the EMG signals were observed by completely isolating the liquid in the cavities. In the case of freshwater, the EMG signals were observed even when in incomplete isolation of liquid. We also calculated EMG signals from an equivalent circuit model of our sensor. We found the same tendency as in the measurement results. © 2019 Institute of Electrical Engineers of Japan. All rights reserved.