This exercise encompassed the construction and use of a microcontroller-based laser refractometer. The instrument, which does not require a high skill level to build, primarily consisted of a line laser, optical sensor, several 3-D printed parts and printed circuit boards, and a microcontroller development board. Construction and testing of the device occurred in upper division analytical chemistry courses, either quantitative analysis or instrumental methods, and data analysis of real-world samples took place in the general chemistry laboratory. Open-source software was used to (a) communicate between a laptop and microcontroller and (b) record data in real-time directly to an Excel spreadsheet utilizing visual Basic for applications (VBA) an event driven programming language that is part of Microsoft Office applications. In addition to collecting the data, general chemistry students used Excel to generate a calibration curve and determine the concentration of ethylene glycol in an antifreeze sample. Student engagement was assessed using a Likert-type survey, and the results were analyzed using statistical methods. Laboratory reports and a postlab quiz were used to assess student learning outcomes.