Air Column Length Measurement in a Sound-Wave Resonance Experiment Using HC-SR04 Ultrasonic Sensor

Abstract

This study evaluates the performance of the HC-SR04 ultrasonic sensor for measuring air column length in a sound-wave resonance experiment at 512 Hz. The sensor's accuracy and precision were assessed through comparison with a ruler as a reference instrument and repeated measurements. The characterization results show excellent linearity with R² = 0.99822. The accuracy test results show an average error of 1.156% and accuracy of 98.85%. The precision test at 10 cm yielded an average precision of 96.19%, while the precision test at 512 Hz (first resonance order) produced an average precision of 98.02%. In the resonance experiment at 512 Hz, the sensor was applied to measure air column lengths at the first, second, and third resonance orders. The measured values were compared with theoretical calculations, yielding an average accuracy of 98.26%. The measurements were conducted in an air-conditioned laboratory at 20 °C. Therefore, the results should be interpreted within the tested experimental conditions and the limitations of the measurement conditions.