P13481: Underwater Leak Detection
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Feasibility Testing

Table of Contents

Introduction

This page highlights data that we've collected and processed in order to verify that our method of leak detection is viable. We have tested common leaks created in above ground pools- examples of how these leaks are created are shown below.

Leak Created By A Pool Brush

Leak Created By A Pool Brush

Leak Created By A Pool Ladder

Leak Created By A Pool Ladder

Test Setup

Our test environment consisted of a 12 foot diameter inflatable pool in a garage.The vinyl pool allowed for us to make holes of varying size, record leaks, and then patch the holes back up.

Test Pool

Test Pool

Equipment Used

The hydrophone we used for testing was purchased from Aquarian Audio Products. We also plan to use this hydrophone in our prototype design.

Hydrophone

Hydrophone

Preamp

Preamp

Results - 10/01/2012

Our first round of testing took place on 10/01/2012. Under all cases, leaks were not only able to be heard using our hydrophone, but all size leaks were confined to a 1 kHz to 6 kHz frequency band. Excerpts from the data collected are shown below as FFT (Fast Fourier Transform) MATLAB plots.

FFT of leak noise of one-inch hole, 1 inch away.

FFT of leak noise of one-inch hole, 1 inch away.

Audio file for this plot can be found HERE

FFT of leak noise half-inch hole, 8 inches away.

FFT of leak noise half-inch hole, 8 inches away.

Audio file for this plot can be found HERE

Results 10/17/2012

We tested again on 10/17/2012 in order to verify the leak frequency band before we built any circuitry. The results were consistent with the first round of testing. A few excerpts from the collected data are shown below.

FFT of leak noise at declining 1 foot distances, from 1 to 6 feet.

FFT of leak noise at declining 1 foot distances, from 1 to 6 feet.

Audio file for this plot can be found HERE

Waterproofing Results

We were able to water proof the unit by vacuum molding a two piece outer shell and bonding the pieces together using Bondo. This resulted in a waterproof case that could withstand the depth of our test pool which is about 4 feet.

Vacuum Mold

Vacuum Mold

Waterproof Testing

Waterproof Testing

Prototype

Prototype