Development of Lora Battery-Free Water Leak Detection

Abstract

This study explores the development of a battery-free water leak detection system that leverages energy harvesting sensors and LoRa (Long Range) communication to overcome the limitations of Bluetooth Low Energy (BLE) technology. While BLE offers low power consumption, its range is limited to approximately 50 meters, making it unsuitable for wide area monitoring. In contrast, LoRa provides transmission distances of up to 10 kilometres and excellent indoor wall penetration, enabling broader scalability for smart infrastructure applications. The goal of this research is to integrate LoRa modules into a self-powered sensing platform, eliminating the need for conventional batteries or wired power sources. However, the transition to a battery-free system introduces a key challenge: the LoRa module requires high peak currents, often exceeding 100 mA, for successful activation and data transmission, which electrochemical energy harvesting devices cannot directly supply. Experimental testing showed that single energy harvesting cells failed to activate the LoRa chip due to insufficient current, despite producing sufficient open-circuit voltage. Attempts to connect sensors in series or parallel offered partial improvements but still lacked the required stability and power density to sustain beaconing. These issues were further compounded by mismatched performance between cells and high internal resistance, limiting energy transfer efficiency. To overcome power limitations, the system integrated a DC-DC boost converter and a 100 mF supercapacitor to store and deliver energy in short bursts for LoRa transmission. Enhancements in sensor design and enclosure durability improved activation speed and energy reliability. Electrical tests confirmed efficient energy use and successful LoRa beaconing, demonstrating the feasibility of battery-free, long-range leak detection for scalable, low-maintenance monitoring.