Experimental Physics with Arduino: waves in a tensioned string

Abstract In this work we have developed an apparatus for studying the sound emitted by vibrating strings using the Arduino platform. Steel and nylon strings were attached to a device that made it possible to apply a strain to the strings and investigate the relationship between this force and the frequency of the sound emitted using, together with the Arduino, respectively, a force sensor based on the HX711 and an audio sensor based on the MAX4466 circuit. The audio signal has obtained from the analog-digital (A/D) conversion of the electrical voltage at the output pin of the sound sensor. To obtain a more reliable signal, we implemented programming strategies that allowed us to increase the A/D conversion speed and reduce the impact of Arduino-PC communication latency. After spectral analysis of the audio signals, we found a good agreement between theoretical predictions and the results obtained experimentally showing, thus, that the adopted approach can be used both in the development of experimental classes as well as in the manufacture of instrumentation for research in the acoustics.