Intro
This blog summarizes the sub-surface camera project that also tests Amphenol waterproof connectors and a watertight Hammond enclosure. The Hammond enclosure features a clear lid, which allows a non-waterproof camera to be kept dry while looking through the window during immersion. The immersible camera system is mounted on an shaft with hinges and a sliding lock that allows the angle of the camera enclosure to be adjusted from vertical to horizontal. A LattePanda computer was included in the kit and it is used to view the camera in real-time on an LCD, and record video when desired. The display and computer are mounted at the top of the pole using 3D printed brackets.
Sub-Surface Camera System Components Image
The Kit
A primary objective of this project is to evaluate the experience of working with the component kit provided by Amphenol, Hammond Manufacturing and element14. This section touches on my impressions of the kit components in a short video:
Extra Components
This project did require some extra components, some of which I already had in my stash.
- pla plastic for 3D printing
- solar charged battery
- USB camera
- carbon composite hockey sticks
- an HDMI LCD (actually a 2nd one as well)
- a heatsink computer chassis (ordered but did not arrive)
- wireless keyboard/touchpad
- USB memory stick
- HDMI TV
- USB A receptacle connectors (I messed one up)
- USB A plug-to-plug adapter
- USB extension cable
- 2 bungee cords
- a fishing lure
- a greens repair tool
- USB power cables
- an HDMI cable (another one was ordered but didn't arrive yet)
- 4 M3 screws
- 4 4-40 screws
- 2 wire-ties
- fishing line
A few of the main accessory components are shown in this image:
And of course various tools, instruments, power supplies and consumable supplies were used in the project.
There was a deceptive amount of material needed for this project and even though I had some of it, the costs did start to add up. Fortunately, I have a day job.
The Build
The design and build part of the project was performed in several stages - explained below this image of the 3D printed parts (images not to scale).
The 3D parts took about 20 hours to print.
Camera Mount
The camera needed to be securely mounted just under the surface of the enclosure's clear lid. A 3D printed frame was designed that took advantage of the internal threaded inserts to screw in it into place. It ended up to be quite an irregular shape since it had to avoid everything else in the box. The mounting screws are right in the corners, so special washers with handles on them were printed to allow the washers to hold the screws in position for screwing.
Enclosure Mount & Mechanism
The enclosure needed to be secured to the main shaft without compromising its waterproof seals. This was accomplished by making 2 endcap frames that are clamped together using bungee cords. The bungee cords are anchored in place by plastic tabs (made from wire ties) that are easily displaced, with the correct knack, to allow the box to be quickly installed or removed from its frame. The shaft mechanism video below shows how the removable bungees attachment works.
The box also needed to be able to to pivot more than 90 degrees. Normally a hinge with a wingnut might be used to do this, but this box is too large and too buoyant for this to work with a regular wingnut. Plus the wingnut might be under water when you want to adjust it. This angle adjust function was accomplished by designing pivot joints on both frames that allow the connecting shaft and strut to be hinged at the enclosure. This adjustment system is also shown in the shaft video below.
Shaft & Strut Mechanism
The box needed to be able to to pivot more than 90 degrees and have this angle controlled from above the water. This was accomplished by using a strut from the main shaft that could be pinned to the main shaft. The strut and the main shaft re connected to the box frame hinges such that the triangle formed by the main shaft, the box and a strut define the angle of the box. It is easier to see how it works in a video:
Computer & Display Mount
The computer mount was tested to fit snuggly on the shaft. It has a mounting hole for a screw to ensure it cannot come off, but this was not needed for the testing that was performed.
Likewise the display mounting slot was a nice snug fit that did not need an extra screw to secure it for this testing.
Functional Testing
Power-up and functional testing was also done in several stages:
LattePanda
I did a lot of work on the LattePanda to try and make it into an embedded Windows development platform, however there just wasn't enough memory for it to do what I wanted. It is still a nice little computer and I was able to use it to view the underwater camera in real-time on an LCD and record video whenever desired. I tested its ability to connect to the internet and record video as well as its ability to monitor the camera, display real-time video on an LCD and record video.
Camera & Wiring
The camera was first tested on a desktop PC to make sure it worked before attempting custom wiring. Next the cable inside the waterproof box was wired up. I ended up having to do this twice because the adhesive-line heatshrink tubing I used initially to cover the USB connectors leaked adhesive into the connection area. The waterproof bulkhead connector is a receptacle, which meant I needed to use a gender changer to allow an extension USB cable to be used to go from the enclosure to the computer. Cables wired like this are available, but I didn't have one, fortunately I did have a gender changer.
Here is a system test using a TV to supply interesting video content:
Computer & Display Mounting System
The computer housing had to be custom designed to fit onto the top of the rectangular shaft, because the metallic heatsink chassis I ordered was not going to arrive before the contest deadline. The LattePanda chassis prevents the circuit board from being touched, while allowing good airflow across the card. This is important since the 3D printed chassis might get soft if the circuit board gets too hot.
The 3D printed display mount was designed to plug onto the computer chassis. Unfortunately, the display needed a mini HDMI cable which is also on order but has not arrived, so for testing I used a larger display I had from a previous project - mounted on its own tripod.
Battery Mount
The solar recharged battery needed a simple sleeve bracket to mount it below the computer on the shaft.
Pole Operation
The pole and strut system was tested to ensure it could be adjusted to a range on angles that far exceeded the requirement of about 130 degrees. The system allows any position to be fixed by drilling a pinning hole at the appropriate location on the shaft.
Water Testing
The project culminated with validation of the full system working during immersion tests. The camera system worked well, with a nice high frame rate to show motion of any subject matter. The shaft made positioning of the camera easy without bending over and the angle adjustment mechanism worked well to allow the camera either a horizontal view or a downward view. And the main test to see if any connectors leaked, or if the enclosure leaked, successfully proved that no water entered the enclosure. The downward view in particular turned out to be surprisingly ergonomic, with the buoyant box supporting the weight of the entire apparatus.
Discussion
It is a pleasure to work with quality components. Making watertight seals in a plastic enclosure with 7 holes in it can be a highly problematic endeavor, but Hammond Manufacturing made it an extremely simple exercise. They not only designed a strong plastic enclosure with a great o-ring seal and captive fasteners, they also custom milled the connector cutouts to accommodate the particular connectors supplied by Amphenol. Their design allows the case to be disassembled and reassembled without using any adhesive sealants to gum up the process.
What Went Well
The handle washers turned out to be a really useful invention.
All of the Amphenol connectors worked perfectly to prevent water ingress. The connectors selected for the kit also provide some very useful connector adapter functions between various connector standards as well as bulkhead mounting. This makes them quite useful and reusable in future projects.
The Hammond Manufacturing enclosure not only worked perfectly to prevent water ingress, it also provided a nice clear window for underwater camera work. Additionally, it made mounting of internal components easy and their accurate machining job of making connector cutouts made it a breeze to mount connectors with a full watertight seal.
Th buoyancy of the box made its ungainly size a non-issue by supporting its own weight. Normally a box that size on the end of a pole would be awkward, but once in the water its bulk becomes unnoticeable and it can be steered around with almost no effort.
Although the LattePanda did not have the resources I wanted for future projects, it ran Windows just fine and Windows built-in camera functions were all that was needed for this project, which made software development a non-issue.
The shaft and strut adjustment mechanism for the camera angle worked well and allowed easy control from well above the water.
All the 3D printed parts worked well without redesign or reprinting, which was fortunate because there were a dozen 3D parts that took about 20 hours to print, not counting design time.
Issues Encountered
I did not have any significant issues with the Hammond enclosure or the Amphenol connectors, they performed extremely well. I did need to trim back the internal card guide ribs around one of the connector cutouts in the Hammond box - to provide a flush surface around the connector, but the cutout hole itself was nice and accurate.
My biggest issue with the kit was that the LattePanda did not have enough memory to implement my future plans for it, however it did have enough resources to fully test this application.
I found out the hard way that the adhesive in adhesive-lined heatshrink tubing can flow into connectors. This cost me a connector (not one of the kit parts) - fortunately I had a spare.
I did have issues with an HDMI cable and a LattePanda chassis not arriving in time to meet the deadline, but workarounds were successfully implemented, and when those components do arrive they will still be useful.
It took a deep dive search to dig up the mating wireless module for my wireless keyboard and it took a serious refurbishment effort to remove the gooey mess that the keyboard case had deteriorated into. Fortunately the keyboard battery can still hold a charge.
Summary
The kit included a long lineup of very nice Amphenol waterproof connectors and and excellent Hammond Manufacturing waterproof enclosure to test their ingress protection capabilities. Experimenting with ingress protective properties of connectors and enclosures is primarily a mechanical exercise, but I wanted to use a real electro-optical & software application in the testing to give it a real world application perspective rather than simply doing some leak testing. I also wanted to try to produce the project as a fairly rich multimedia blog. I ended up with over 50 videos to edit, so hopefully that objective was met.
Risking some real electronics that would die if immersed in water adds a little subtle drama and demonstrates my confidence in Amphenol and Hammond Manufacturing abilities to make waterproof components. I had originally planned to test the box with no electronics inside before testing with the camera, but after experiencing the components during assembly, I ended up being confident in having the camera in the first water test. And my confidence was well placed - nothing leaked.
As far as the kit, the experiments and working with the supplied components, I simply have only good things to say about the Hammond Manufacturing and Amphenol components, they have top notch quality, were easy to use and performed perfectly.
I didn't have my usual quota of fun with this project, mainly because I was in a lot of physical pain throughout the project, but it had some nice highlights and it was very satisfying that the system worked well.
I would like to thank Amphenol, Hammond Manufacturing and element14 for the opportunity to experiment with these components, it reinforced my already high opinion of these suppliers.
Links:
Waterproof Connectors - Camera Build
Pole Mechanism for the Waterproof Camera
LattePanda and LCD Pole -Mounted Chassis
Hammond and Amphenol Experience
