Development of a low-cost experimental platform with preliminary numerical analysis for the study of ultrasonic sound propagation speed

In recent years, universities have sought alternative methodologies to sustain the teaching–learning process, driven by the expansion of virtual classes and limited resources in many insti-tutions. In this context, this study investigates the influence of temperature and humidity on the speed of sound wave propagation (SSW) using a low-cost experimental setup complemented by numerical simulations. A hermetically sealed container was instrumented with sensors to meas-ure sound speed, temperature, and relative humidity, using an Arduino UNO development board. Four experimental conditions were analyzed, varying water presence and heating. In par-allel, a numerical model using harmonic acoustics is proposed. Experimental results showed an increase in sound speed with temperature, consistent with theoretical expectations, while the in-fluence of humidity was less pronounced due to near-saturation conditions. The presence of liq-uid water increased absolute humidity through evaporation, affecting measurements. However, measured SSW values were lower than theoretical predictions, likely due to sensor limitations and uncertainties under high humidity. Numerical results also diverged from experiments be-cause of simplified boundary conditions and the absence of thermal and humidity gradients. De-spite these limitations, the proposed approach indicates the feasibility of a replicable, low-cost system for educational and research applications, with potential improvements through en-hanced sensor calibration and multiphysics modeling.