Integration of a Self-Powered Sensor and Electronics to Produce a Battery-Free, Wireless, Water Leak Detection Device

Abstract

Water damage accounts for 73% by dollars lost in commercial real estate claims [1]. Water leak detectors are a key solution to the problem but suffer from numerous drawbacks, namely high costs, lack of scalability, and over-reliance on batteries. This severely limits their usability in large-scale multi-residential and commercial applications. Small, self-powered sensing devices that operate from water exist in research, but examples of market ready technology that relies on alternative standalone power-sources are scare. Here, the objective is to create a battery-free water leak detector using a recently published water-powered sensor. The sensor consists of two electrode layers, which, when exposed to water, produces usable power output. This power can be collected and used to operate a Bluetooth device for wireless data transmission. The work here involves integrating the sensor materials into a custom enclosure design so that they can be used as a typical water leak sensor would. Multiple design iterations were tested to produce the first prototype design. This involved developing the contact methods from a wire to the electrodes of the sensor, designing methods for the water to reach the electrodes, features to keep the packaging closed, and overall device layout and wire routing. The sensor prototype performance at this stage was significantly worse than previously reported sensor performance without any mechanical enclosure. Improvements suggested included better mating force between the sensor enclosure lid and base, easier assembly, and manufacturing quality checks to name a few. The identified design flaws were improved upon, and a second major design iteration was produced, this time by injection molding. The sensor performance was comparable to the unpackaged measurements. Notable performance achievements include a yield rate of 100% for a sample size of 24, and furthermore, all devices activating in less than 1 minute. The results of testing with the final design iteration are promising enough to conclude that the sensor materials employed in the water leak sensor design are feasible to use for water leak detection applications.