Sugar/ethanol level measurement in liquids using analog refractometer and digital image processing

This paper presents a novel method for remote monitoring sugar/ethanol levels in liquids using an analog refractometer, a digital camera, and an embedded Internet of Things (IoT) device. The main goal is to develop a cost-effective technology that allows remote measurement of this critical wine parameter. A printed 3D model is used for component mounting to keep a constant lens focus. Color image captured with the proposed device is sent via Wi-Fi network to a remote server for processing. Image processing methods are utilized to convert the image from the refractometer's Oechsle scale to the sugar/ethanol level value. The device is tested with different levels of soluble sugars, and the results are compared with human readings. The conducted test gives promising results with less than 2 % relative error for sugar levels in the winemaking process. The proposed device can be used for sugar/ethanol level measurement during wine production. Flexibility and openness of the proposed IoT system has advantage over the existing solutions for sugar/ethanol measurements.