A Light Spot Centroid Determination Method for Accurate Digital Refractometer

In this paper, we propose the development of a highly stable and low-cost refractometer for measuring the sucrose concentration. Laboratory-grade refractometers are prohibitively costly and impractical for everyday applications, while currently accessible low-cost commercial alternatives suffer from insufficient stability and precision. To address this gap, our proposed refractometer replaces the costly CCD sensor and light source with a conventional LED and a cost-effective CMOS sensor. By analyzing the output waveform pattern, we achieve high precision with an accuracy of 0.1%, which is suitable for individual use. We repeat 100 measurements on various samples to determine the dependability and consistency of our refractometer, and the results demonstrate its accuracy. The algorithm operates on a 480 MHz ARM processor and acquires data within 20mS. Our instrument provides an affordable and reliable method for measuring sucrose concentration and demonstrates stability and accuracy compared to existing cost-effective options.