  This study aims to develop a low-cost refractometer for measuring the sucrose
content of fruit juice, which is an important factor affecting human health.
While laboratory-grade refractometers are expensive and unsuitable for personal
use, existing low-cost commercial options lack stability and accuracy. To
address this gap, we propose a refractometer that replaces the expensive CCD
sensor and light source with a conventional LED and a reasonably priced CMOS
sensor. By analyzing the output waveform pattern of the CMOS sensor, we achieve
high precision with a personal-use-appropriate accuracy of 0.1%. We tested the
proposed refractometer by conducting 100 repeated measurements on various fruit
juice samples, and the results demonstrate its reliability and consistency.
Running on a 48 MHz ARM processor, the algorithm can acquire data within 0.2
seconds. Our low-cost refractometer is suitable for personal health management
and small-scale production, providing an affordable and reliable method for
measuring sucrose concentration in fruit juice. It improves upon the existing
low-cost options by offering better stability and accuracy. This accessible
tool has potential applications in optimizing the sucrose content of fruit
juice for better health and quality control.
