Low-cost engineering experimentation laboratory kit designed for at-home project-based learning

Abstract

During the Spring 2021 semester, the third-year Engineering Experimentation course at the Cooper Union was administered virtually due to the COVID-19 pandemic. The online format presented many challenges to teaching a hands-on, project-based laboratory class. To provide students with the experience of performing real engineering experiments, a low-cost laboratory kit was assembled and sent to each student. The kit included a microcontroller to serve as a data acquisition device, two electret microphones, and electronic components necessary to collect acoustic data. All of the students used this equipment to run a speed of sound laboratory by determining the time an impulsive signal took to travel between the microphones placed a known distance apart. For the final project, two teams of students conducted independent research of acoustic phenomena and further developed low-cost solutions. One team constructed an impedance tube from PVC pipe to measure the absorption characteristics of unknown materials. Normal incidence sound absorption coefficients were calculated for four frequencies by measuring the standing-wave ratio in accordance with ASTM standard C384. The second team built two experimental apparatuses to demonstrate the Doppler Effect. Both at-home Doppler experiments were able to clearly show the shift of the observed frequency of a moving source.