Design of a Smartphone Plastic Optical Fiber Chemical Sensor for Hydrogen Sulfide Detection

We present a low-cost, handheld plastic optical fiber (POF) sensor for hydrogen sulfide (H
₂
S) detection integrated onto a smartphone. The sensor uses smartphone flashlight as a source and camera as a pixel-based intensity detector. The POF is interconnected to the smartphone with a 3-D-printed connector on both source/detector sides. The sensing mechanism is embedded in the fiber link, making the system an all-fiber smartphone architecture. A mobile application handles data acquisition on the Android operative system. The sensor is functionalized for H
₂
S detection through silver deposition on the POF outer surface. Experiments demonstrate the feasibility of the sensor system as the presence of H
₂
S is successfully measured through an increase of optical losses through the POF link. This cost-effective, scalable, and compact sensor is promising for application in environmental sensing.