The Serpe group has been developing optical devices (etalons) that can be used for sensing and biosensing applications. Like butterfly wings and beetle shells, the colour of the etalons are a result of light interference after interaction with the device’s structure. Etalons are cost effective devices that can quantify analyte concentration in real time. Monitoring water quality is extremely important for minimizing water-borne illnesses, and the current practice is to sample and transport the water to a lab for analysis. Water analysis is costly, and typically requires trained personnel to run the samples in a lab setting. Utilizing 3D printing, photo boxes and holders have been designed for facile use with the etalons. The group is using reflectance spectroscopy along with RBG analysis of photographs acquired with the photo boxes to characterize the etalon’s colour change in response to analytes. The end goal is to have a portable device that can be used in the field to quantify various analytes in water samples.