Electronics tube depth test V


#1

I can see the light at the end of the tunnel...

I count myself as very fortunate to have found a webcam, that works in oil, on my first try... but it sure lead to disappointment in the others!

The HP Camera could not focus (it was auto focus with no manual override)

The Raspberry pi camera has a very small lens case and too few threads to focus. I even added the lens frame from my borked logitech cam but it was seated just a little to far off the sensor or something. (it was very close to being focused, but not close enough)

Also, sadly, after 9 months, either directly in, or at least wet with, oil, my little logitech that could, no longer can. It still puts out a signal (that seems to be affected by the light going in) but it is just blocks of color.

So I must adapt!

I hot glued the Raspberry pi camera to the acrylic cap sealing it. Then I glued a small acrylic cylinder around it. Next I poured in a clear epoxy till it covered the whole board.

From the front.

It works!

Here is my new 1/4" E-Tube with thick endcaps.

Here is the Raspberry pi camera Module. Inside is the Raspberry and camera, voltage converter and Homeplug adapter.

On the left: Testing before sealing up. Middle: Sealed up and pouring the oil. (lessons learned and applied) Right: All done! Complete with questionably useful, convection powered, cooling tube! The return fitting has a short hose inside, piping the ocean cooled oil directly to the bottom! Hooray!

Testing confirms, with happy leds (and a video stream), that all is working properly. (it is possible that the focus was set a little short. It will certainly be fine for the job at hand, but I will have to think hard about who i can blame for this)

I left it on for 1 hour and 20 mins and it was still running. There was some warmth in parts but not too hot. I would not say the cooling tube was activated, but if it was left for a longer period of time, and had nice cold ocean water all around it, I'm betting it would positively trickle through that tube!

Now that I have the two camera enabled modules set up, plus the light modules, I have only to:

Assemble the rig

Test everything with batteries

File the 2 additional e-tube ends

Test cable to see how long I can get it whilst still having a signal.

Set up ad-hoc slip ring(s)

Set up measuring wheel

Fill Battery Packs with oil.

Test everything with oil filled battery packs

Rent a boat

Other things I have forgotten but will hopefully remember before setting out. :D

Then pray for calm weather...

Or Google it.


#2

Loving these updates. Keep up the good work.


#3

Ditto- this is GREAT! Also, I wanted to let you know that after your initial post RE using a webcam in oil and just refocusing it, I tried the same thing with one of the Genius-KYE F100 webcams we send out with the OpenROV kits, and it worked great!

I think that the lens systems for these cameras have multiple lenses and there's a sealed air gap between them which is why the focal length stays about the same even when everything else is flooded with oil. My guess is that if the camera were brought down to enough pressure, the air cavity inside the lens system would implode. I'll try to do some testing to see what pressure that actually happens at, but in the mean time it's great to know that works so well... nice work!


#4

Here's a link to a similar method as yours: http://gasstationwithoutpumps.wordpress.com/2011/02/13/waterproofing-cameras-for-underwater-rovs/

Why are you filling your etube with oil (I'm guessing mineral oil)? For greater depth capability? Are you doing anything with different with your thrusters?


#5

Thanks Owen! I will try. :D

Eric, that is awesome to hear! I considered testing my webcam from the kit, (and filling my OpenROV e-tube with oil) but I didn't have a replacement camera yet and I didn't want to end up with no ROV. :)

I wondered if it had a double lens or not (the optimist in me said "that's crazy! They would never do that!" and the pessimist just rolled his eyes at him.) The HP (auto focus) webcams definitely have two lenses. I drilled a hole between them from the side to let the oil in. I broke things in the process, so I didn't see if it had any effect.

A friend of mine informed me of a liquid lens that came in a 'snake cam' webcam. Someone pulled it out and showed how it worked in a video which is posted on makezine.

This lens has a really long focal range, plus its liquid so should play nicely with ocean pressures. :) It kinda disappeared after showing up in the snake cam. Because it was too good for a mere webcam rather than because it was crappy.

I would love to hear any results you get from testing how deep the lens can go!

Stretch, For greater depth yes! But so far it is only the extra camera module I am putting together for the depth test that I am putting in mineral oil. I bought a thicker tube (1/4") and made thicker endcaps that I am hoping will keep my e-chassis safe/dry/3D.


#6

But no I haven't done anything with the thrusters. :)


#7

I was going to begin experimenting with dipping the motors we're using in paraffin wax. It seems that most of the corrosion issues are chiefly aesthetic, but it might still be nice for everything to stay in tip top shape. My thought was to submerge the entire motor assembly (inner and outer parts together) into a bath of melted wax several times, then break the bell free by rotating it and allowing it to wear out its own path. Any thoughts?

~E


#8

Do the motors get hot enough to melt the wax when they are running? Wax might keep sand out better than epoxy or something hard. Might be hard to break the bell free. :)