# Noninvasive Acoustic Recognition of Water Flow Sources for Human Activity Monitoring in Smart Homes

## TL;DR

A smart home system uses sound to detect water usage in bathrooms, helping monitor daily activities without changing plumbing.

## Contribution

A noninvasive acoustic system for identifying water flow sources in smart homes with high accuracy.

## Key findings

- The system identifies four bathroom fixtures with 90.6% accuracy using a single microphone.
- Acoustic signatures enable detection of water sources and their usage duration.
- The system requires no plumbing modifications and is adaptable to different environments.

## Abstract

This paper presents a noninvasive system for identifying water flow sources with the final goal of supporting human activity recognition (HAR) in activities of daily living (ADL). The system employs a single microphone to capture ambient sounds within a room and detects active water sources based on their acoustic signatures. The audio signals are converted into time-resolved spectrograms, which are processed via time- and frequency-domain convolution and subsequently classified using a neural network. This approach enables both the identification of specific water sources, even combined, and the measurement of their usage duration with an overall accuracy of 90.6%. The study focuses on four common bathroom fixtures: toilet, bidet, shower, and washbasin. The proposed system is adaptable to various environments, requires no modifications to plumbing infrastructure, making it suitable for smart home and digital health applications.