A portable multi-band optoelectronic system for identifying and measuring the concentration of fluorophore substances

We describe a device that can identify and measure the concentration of fluorophore substances in a light conducting environment, typically a liquid suspension or solution. The method is based on multi-spectral fluorescence measurements, achieved by exciting the unknown substance with light emitting diodes (LED) of different wavelengths, and subsequent processing of the acquired data with a neural network for spectral signature identification and concentration measurement. Our photodetector design exploits the inherent capability of diodes to act as photodetectors when reversed-biased. Hence, the system's front end consists of a set of LEDs successively used as light sources and photodetectors as they are forward and reversed-biased.