Odor-based incontinence sensor

A low-cost “artificial nose” is required to monitor inconvenience of elderly patients in nursing homes. With the aim of identifying a small array of inexpensive sensors whose response vector could provide an unambiguous signature at a useful sensitivity level, we characterized the sensitivity of seven easily available solid-state sensors to fecal component gases and vapors, and to potential interferences anticipated in the environment. The sensors´ dynamic responses in a rapid periodic heating and cooling cycle proved substantially quieter than their DC responses at constant temperatures. However, large sensor-to-sensor variability combined with undesirably, high sensitivity to humidity proved so vexing that the practical prospects for this approach were deemed discouraging. An alternative approach using the differential response of a matched pairs of sensors, with one of the pair equipped with a filter that traps fecal component gases and vapors, is now under investigation