Ls-liquid: towards container-irrelevant liquid sensing on smartphones

Abstract

Liquid sensing utilizing the wireless signal provides a great convenience for lay consumers to ensure the quality and purity of the liquids (detecting the food additives in the beverages), and detect kidney disease (tracking the protein in the urine), which is very important for our daily life. In this paper, we propose Ls-liquid, a system that employs a commodity smartphone to sense liquid in the common containers without a specialized setup. Our work arises from the acoustic impedance property, in that different liquids have different acoustic impedances, causing reflected signals of liquids to differ. Our experimental evaluations demonstrate that Ls-liquid is able to identify one kind of food additive in four different beverages with over 90% accuracy, and can measure protein concentration under 1 mg/100 mL in the urine. Ls-liquid is also robust to the environment and container changes.