Breath Timing Monitoring Using Spring Coil

We describe a non-invasive breath monitoring method using spring coil which is used to detect the movement of the body surface due to breathing. In this method, subjectwares a vest with the spring coil on the inner side. Therefore, it is compressed by inspiration or prolonged by expiration. This change in length of the spring coil can be detected as change in electrical inductance of the coil. Based on this principle, we made a monitoring system of respiration. This system has three detecting positions, that is, the chest, abdomen, and back. Monitoring experiments of breath timing were performed for some healthy subjects. As results, this sensing system is able to detect the breath timings of subject sleeping on the back or abdomen and to check the sleeping position on the abdomen or back, simultaneously. It was confirmed that this system can also detect the paradoxical breathing in which phase of movement of the abdomen is opposite to that of the chest.