Design Verification

Once we completed the physical prototype, we were able to begin testing the finished device. Many of the concerns we are testing for can be seen in the Design Failure Mode and Effect Analysis (DFMEA) in Appendix 18. All safety considerations mentioned in Appendix 13, the Design Hazard Checklist, were considered when testing. Note that we did not have time to complete some of the desired testing procedures, and instead focuses on making sure we had the core functions working properly.

i. Camera Resolution Testing

Before assembling the entire probe, we performed some initial tests on the camera resolution. In this test, we found that both camera have a minimum of ~450 DPI when looking through an acrylic viewport and mirror acrylic prism. We also found that the glass prism had slightly better resolution, although not a huge amount. Unfortunately, the test images we printed were only able to measure to 450DPI and we could not see the cameras’ upper limit of resolution. However, based on the image clarity at 450 DPI is did not seem unreasonable to assume the cameras could reach 600DPI of resolution. Since the cameras were at least in the ball park of the correct resolution, we decided our time was better spent finishing the actual probe rather than continuing to test the cameras in their unassembled state.

Test Procedure:

1. The cameras were mounted through holes in a cardboard box looking down at a resolution test chart.

2. Light was applied with inside the box through a different hole to apply even lighting. 3. A live feed was recorded to focus the cameras

4. A still image of the resolution chart was captured and examined and the camera resolution was calculated using the formula provided on the test chart

ii. Electronics Testing

Electronics testing was performed concurrently with development of the software, and so cannot be narrowed down to a few tests. There were some initial proof of concept tests, such as ensuring that the battery, LED buck, and solid state relay could correctly control the high powered LEDs, but most “tests” were performed countless times while developing the code. The other main hardware electronics test was

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to make sure that a signal from a Raspberry Pi could correctly turn on the battery and Raspberry Pi in the probe.

iii. Pressure Vessel Leakage

In this test, we found that the pressure vessel is water tight in shallow water for several hours, as seen in Figure 38. We also found that it does not spring any leaks at approximately 10m of depth over the course of a few minutes. One thing to note is we found that water can wick through the external LED wires. If the wire casing is nicked or the epoxy is cracked, water may be able to find it’s way into the pressure vessel slowly. Fortunately, the leak is slow enough that it should be visible in the lower camera’s field of view before the water gets high enough to damage electronics.

Figure 38: Pressure vessel bucket test

Test Procedure:

1. All seals were lubricated with silicon based dive gel and ensured they were fully tightened 2. Pressure vessel was left for several hours in a water filled bucket.

3. Pressure vessel was opened and inspected for any signs of water or leaks.

4. Once confirmed we do not leak at low pressure, we went to Avila pier and dropped it off into the water and left it there for several minutes, as seen below in Figure 39. The deepest area we were able to find was approximately 10m underwater.

5. Due to attracting the interest of several nearby seals, we decided to recover the device after about 10 minutes of submersion lest the Ethernet cable get bitten.

6. When before opening the pressure vessel we looked through the view ports and confirmed there were no signs of water incursion.

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Figure 39: Pressure vessel pier test iv. Fully Assembled Operation

Once we knew all of our electronics components function properly and that our pressure vessel is watertight, we were able to begin fully assembled testing. This was primarily done to make sure the software properly functioned and all controller functions were working.

Test Procedure:

1. Device was powered up using controller and we ensured we were receiving communications from the probe.

2. We then tested to make sure we could toggle the lights and receive a live feed from the driving camera.

3. We then took a photo and ensured we could properly review it on the controller 4. Once we had an image saved, we powered off the probe using the controller

5. We then recovered the captured image from the controller on a USB flash drive and ensured it could be read on a full size PC

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