OPTIMIZATION OF BATTERY-FREE WATER LEAK DETECTORS

Abstract

Battery-free water leak sensors offer a sustainable solution for real-time leak detection by harvesting energy from water-triggered reactions to power communication modules such as BLE (Bluetooth Low Energy). A key challenge for their practical use is ensuring reliable and rapid activation of the BLE electronics under varying conditions. This work investigates how material loading and sensor design parameters, such as water inlet size and elevation, influence activation time, current output, and structural stability. In this study, the influence of powder mass loading, water inlet size, and sensor elevation on activation time and electrical output was systematically investigated. Among the different mass loadings tested, the 400 mg configuration consistently demonstrated superior performance, achieving both shorter activation times and higher current output compared to other loadings. This optimal behaviour is attributed to a favourable balance in packing density, which improves conductivity and current generation without impeding water penetration. Design parameters such as inlet size and sensor elevation were also found to significantly affect wetting dynamics and activation timing. Further validation in natural water conditions confirmed the robustness of the 400 mg configuration, showing consistent BLE activation across 25 test samples. Mechanical drop tests revealed that lower mass loadings (e.g., 300 mg) resulted in pellet instability and performance degradation, while 400 mg maintained structural integrity. Overall, the results highlight 400 mg mass loading in combination with optimized structural design as the most effective configuration for reliable BLE activation. These findings provide critical insights for advancing battery-free water leak sensors toward real-world applications in leak monitoring and water damage prevention.