Reimagined Microphone-Free Acoustic Volumetry: An Open, DIY Platform for Global Phenotyping

We present a groundbreaking Do-It-Yourself (DIY) acoustic volumetry platform that redefines quantitative measurement by eliminating the conventional microphone. Our design exploits the inherent acoustic-electrical properties of a dynamic microphone cartridge mounted on a sealed chamber--representing the theoretically simplest possible acoustic volumeter. By focusing on resonance peak shifts, our streamlined sensor --utilizing an easily assembled circuit built solely from off-the-shelf audio connectors to split the sound card output between sensor excitation and response recording--delivers rapid, precise volumetric measurements with as few as three frequency points in several seconds. Calibration using both linear and logarithmic models demonstrated a robust correlation between resonance peak shifts and sample volume, yielding root mean square errors (RMSE) of 1.980 L and 1.662 L, respectively. Notably, when applied to a ten-grain assay, these values correspond to an average error of less than 0.2 L per wheat grain, thereby affirming the devices precision across a diverse range of sample volumes. An exclusive Python-based freeware, distributed globally, provides an intuitive interface for calibration and measurement, ensuring that this cost-effective and modular approach is accessible to researchers worldwide. This innovative method not only simplifies traditional volumetry techniques but also paves the way for further optimization, marking a significant advancement for applications across a broad spectrum of scientific fields.