2024 ASEE Annual Conference & Exposition

The goal of the greater project is to provide students with a hands-on learning experience while removing cost as a barrier to participation. These Low-Cost Desktop Learning Modules (or LCDLMs) help students visualize and experience engineering concepts where books would prove inadequate and provide class members with the opportunity to learn as a group and collaborate with one another. LCDLMs have been found to improve motivation and attention while providing direct and vicarious learning opportunities, encouraging information retention in a learning environment.

The latest LCDLM in development for the project is a glucose analyzer kit, which, when completed, will feature a glucose solution containing a sample of unknown concentration, a set of reagents to convert the glucose solution from transparent to red-violet color of intensity correlated to the glucose concentration, and a simple apparatus students can use to read the concentration of the sample. The apparatus is meant to teach students multiple engineering concepts through visual demonstration. Chemicals from a set of reservoirs are pumped through a see-through microfluidics mixing chamber, which leads to a colorimetric reaction based on the amount of glucose present, teaching students about kinetics and, to a lesser extent, microfluidics. Dissolved oxygen is a limiting reagent, which will help students learn about stoichiometry. The mixture then flows into a chamber with two transparent sides. One side allows green light into the chamber, through the red solution and into the lens of a smartphone camera to measure the intensity of the light. This is meant to demonstrate Beer’s law and complimentary colors. The more light that can pass through, the lower the glucose concentration due to the red coloring. Students will need to measure a series of solutions with varied but known concentrations, construct a calibration curve, and then find an unknown solution concentration based on where an absorbance reading falls on the curve.

The DLM is still under development, so continued work and testing needs to be done before a final version can be implemented in the classroom. The final design for the analyzer, how it will be assembled, camera placement, luminosity, etc., is being determined, and up-to-date results will be presented. The geometry of the mixing chamber with attached reservoirs for the addition of reagents needs to be optimized for microliter samples. The plan is to design a 3D model in SolidWorks, then print a prototype using a resin printer and test it for leaks. For large-scale production the chamber could be formed with a 3D-printed mold and assembled with epoxy glue. Microscope slides will be incorporated to provide transparent surfaces above and below the reaction chamber for spectrophotometry.