A novel breathing condition sensor using plastic optical fiber

A. novel plastic-optical-fiber (POF) sensor for detecting humidity change in the vicinity of nose and mouth has been studied. A cladding layer of the POF-type sensor head, which consists of the mixture with hydroxyethyl-cellulose and polyvinylidenefluoride, causes swelling by attachment of water molecules including in human respiration. Using this effect, an optical breathing condition sensor was fabricated and confirmed to operate with good properties. This system can be used for monitoring several breathing conditions in hospitals and in home care.