Go with the Flow

Project undertaken in course year 2021-2022 with Amazon

Project Goal

Create an affordable product to monitor water consumption at water outlets throughout the household for renters and homeowners to use with ease

Project Motivation

The scarcity and worth of water creates the following predicaments: devastated wildlife and costly water monthly bills. Although the residential sector is not solely responsible for the scarcity of water, homeowners heavily contribute to the infrastructure's total water consumption. Therefore, we would like to promote water conservation within the residential setting to protect our most valuable resource.


As water becomes more scarce in the state of California, residents begin to complain about the rising price of water. They would like a product that measures their household water consumption, but the current market only offers expensive products which require direct intervention with plumbing. Renters and homeowners would prefer affordable and easy-to-install water monitoring systems to get them committed to conserving water in the household.

Map of drought levels in California, 2021

High Priority Requirements

  • Easy to install - under 10 minutes with little to no hardware tools

  • Affordable - under $150

  • Safe to use - no sharp edges; electronics are protected to avoid short circuit

  • Long-lasting power source - at least a year long battery life

  • Accuracy if data collection - water usage is quantified in the form of duration; can detect water usage with minimum of 1gpm

  • Data accessibility - water usage data is readily available for user and updates once/day

Ethical Considerations

  • Privacy of data. To address, we moved away from an audio microphone

  • Sustainability - mitigate product's negative effects on the environment. To address, switched to rechargeable batteries to minimize waste


Optimized a 3D printed enclosure that houses a piezoelectric contact microphone and easily straps around a water outlet’s supply pipe. The enclosure includes a stress concentrator interface meant to consolidate the vibrations produced from water flowing within the pipe. The piezoelectric microphone detects the physical vibrations as an input signal and outputs a voltage waveform signal, deriving the presence of water flow from the physical vibrations of the pipe

How system operates

The red dot is the point of contact on the pipe. As the pipe vibrates, the assembly with the stress concentrator (red dot) moves up and down. The contact microphone is the grey ball sitting on the pcb. The pcb is held in place by the housing, allowing the pcb to flex as the stress concentrator moves up and down.

Exploded view

View showing all the components in the system

System in use

System mounted on flexible pipe, with contact microphone in contact

System assembly

Final design assembly casing showing case, batteries, gasket, screws

Test setup

High flow test data

Tested at high flow rate, the blue signal represents the sensor data with high flow rate. The orange signal represents the sensor data when water is off and not running

Medium Flow test data

Tested at medium flow rate, the blue signal represents sensor data with the medium flow rate. The orange signal represents the sensor data when water is off and not running. The sensor is capable of determining medium flow through the pipe.

System mounted on the flexible pipe

Student team

Future Work

  • Integrated pcb

  • Refine data filtering to determine flow rates

  • Implement amplifier to measure low flow rates

  • Develop wireless communication with Alexa