Abstract
Early detection is key to prevent health problems and could be performed by biosensors and chemical sensors. However, a lot of them still need bulky benchtop equipment. This work presents a portable device for measuring fluorescence and light absorption that can be used with optical biosensors or chemical sensors. It uses a small laser diode as a light source and three filter-mounted photodiodes as detectors, all of which are inexpensive, customizable and widely available commercially. The results from our device show good correlation with that from commercial instruments. Therefore, it could be beneficial for early or on-site detection.