LTMVS: Liquid Temperature Measurement with Vibration Sensing Using Smartphones

The real-time measurement and monitoring of liquid temperatures is a critical aspect in diverse fields, including food inspection, medical pharmaceuticals, and industrial machinery. Conventional methods of liquid temperature measurement predominantly depend on invasive external temperature measurement devices. These devices are not only inconvenient for daily utilization but also carry the risk of liquid contamination. Smartphones, recognized for their portability and array of built-in sensors, present an innovative avenue for liquid temperature measurement. However, the use of smartphones for this purpose encounters obstacles in the creation of precise mathematical models and the extraction of informative features. In this study, we introduce a novel method dubbed LTMVS (Liquid Temperature Measurement with Vibration Sensing), grounded on the principle of liquid viscosity. This approach employs the smartphone's vibration motor to generate vibration signals and conducts pattern matching on the echo produced by the cup wall, facilitating non-invasive temperature measurement. We executed extensive experiments using the LTMVS system to measure maltose within a temperature range of 32°C to 63°C. The average absolute error was approximately 1.74°C, and the average absolute error percentage was around 3.91%. These results validate the efficacy and precision of this approach in liquid temperature measurement.