All-POF Chemical H ₂ S sensor designed for smartphone operation

We propose a method to design a hydrogen sulfide (H ₂ S) sensor system, consisting of a plastic optical fiber (POF) and smartphone. The sensor employs the chemical reaction of sulfide gas with silver deposited on the POF. In the proposed design, the sensor is remotely located from the phone, while we use its flashlight as a light source and camera as a pixel-based detector. Moreover, a custom fiber connector socket, fabricated with a 3D printer, is used to couple light to and from the POF. a mobile application for image acquisition and analysis has been developed. a proof of principle study demonstrates the feasibility of the sensor system and the presence of H ₂ S gas was successfully measured by estimating the correlation between the intensities of the captured images with and without H ₂ S gas; a decrease of intensity has been observed for an exposure of several minutes. This cost-effective, ubiquitous, and handheld sensor is promising for application in environmental sensing.