Submarines

Posted byRandall 664 Comments on Submarines

I’m going through a rough period right now. There’s an illness in my family and I’m having a hard time focusing on anything but worrying and trying to take care of health stuff. Everyone is going to be okay, but it’s going to be a difficult four or five months, and I really appreciate your patience and understanding. I’m going to keep putting up comics, but I don’t how much else I’ll be able to work on.

To anyone I’ve been corresponding with, I’m sorry that I may be even more tardy than usual. While davean (the xkcd sysadmin/business manager) monitors the press@xkcd.com address, I know he only forwards to me a fraction of the huge flood of mail that goes there. If you’re trying to reach me personally about something, you can write to me directly at xkcd@xkcd.com, but I’m afraid I won’t able to reply to most of it right now.

I know there haven’t been any posts here in a while. Since most of my projects are on hold right now, I thought I’d share some pictures from one that’s almost done: an underwater ROV. Exploring lakes and oceans has always fascinated me, and while I’ve spent a lot of time snorkeling and free diving, in the end I’m more interested in sending robots than going myself.

I tried to build a couple of ROVs in high school out of scavenged R/C cars and spare parts, but none of them ever worked very well. Last summer, I got interested again and picked up an Inventivity ROV-in-a-Box:

Inventivity ROVIAB

It’s a very basic kit designed to use off-the-shelf parts as much as possible, to encourage people to play with the design or expand on it. I’ve gotten a lot of help and some cool ideas from the company founder, Dr. Karen Suhm, who coaches robotics teams in ROV-building competitions and generally knows everything about ROVs. The kit comes with a good set of underwater motors and a sensitive camera, and this summer I started modifying it to use an Arduino and joystick control, running the whole thing over Cat-5 cable (which significantly lightened the tether). This will also let me add other equipment, like a still camera, depth gauge, compass, and sonar.

It’s very close to being finished—I just have a couple wires to reroute and a leak to seal—but for now, here are some pictures from construction and testing:

Hello.

I made a coupler so the tether could be detached, and added a chamber to hold the Arduino, Ethernet shield, and motor control board. A Python script on the surface translates joystick values into motor speeds, and the Arduino has some code to listen to commands via the Ethernet and control the motors using three TLE-5206 H-bridges. The 5206s offer more protection than some other H-bridges—I initially used some smaller chips, and managed to blow out a couple. (Thank you to mpanetta of #sparkfun for hooking me up with the 5206s.)

A note to anyone who wants to build something like this: the Arduino isn’t actually capable of processing video, so you’ll need to either put an Ethernet camera and hub on the rover, or—if your camera isn’t digital—do what I did and divert two of the Cat-5’s twisted pairs to carry RCA video, running the Ethernet solely on the other half.

This canoe (and everything else in the shot) travels through time.

My friend Mike loaned his canoe for depth testing in Walden Pond, which is (according to data from the 1940s) the deepest lake in Massachusetts

It's about 90 feet down from here.

At the bottom of Walden, there are close to three extra atmospheres of pressure.

In this shot, read left to right.

The zip ties double as binary depth markers. This one is 14 meters.

Shlooooop.

This is the vacuum pump for sealing up wires passing into the sub (it’s sitting atop a draft of the online communities map). If you open up the exterior/water side of a cable and submerse it in a pool of marine epoxy, then apply suction to the dry interior of the sub, it sucks the epoxy through the cable, plugging it up completely. You can also use it to suck all the air out of a wine bottle with random objects inside. It’s fun to see how different materials react to a near-vacuum—particularly if you’ve just drunk a bottle of wine. I didn’t get much more done that day.

Lastly, here’s a clip of the bottom of Walden Pond, about 80 feet below the surface.  This was an unpowered pressure test—the sub was just dangling on a rope—so it’s not very exciting, but it was the only test where I could record the video feed:

The Walden lakebed is pretty dead—the material you’re seeing is flakes of debris stirred up by the sub. In other lakes, we’ve found cooler stuff.  In Seymour Pond on Cape Cod, we had huge catfish fish swim up to the camera and look at it, and we explored a sunken fishing boat on the bottom of Sheep Pond.  I’ve also learned that deck chairs apparently fall off docks all the time—the lakebed 20 feet below the dock on one lake was absolutely littered with them.  When I get a chance to send it to some more interesting places, I’ll be sure to share footage.

P.S. A belated thank-you to the NYC Makerbotters; after I posted comic #743, they fabricated and mailed to me an actual tiny open-source violin.

664 replies on “Submarines”

  1. Hey Randall,

    I’m really sorry to hear about your family’s misfortunes. ‘Been going through a rough year with my family as well. Also no-one in danger of dieing (at least in the short term) but it does take a lot out of one.

    I’ll be thinking of you guys in the coming months.

    Oh yes, and thank you for the wonderful comic, but seriously, don’t worry about us. Take care of your family is fine first.

    A big fan, Cape Town, South Africa

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  3. This too, shall pass. I have been where you are, and though I can’t promise perfection, I know that peace at least is possible, no matter what. I am thinking of you, and sending good vibes. Thank you for all you do, and PLEASE, keep making art! (It helps, I think, no matter what).

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  6. I hope you and your family not only overcome the illness but come out closer, having battled it together. While I always look forward to reading the new comic before my MWF classes, I know some things are more important… Maybe my schoolwork should be, too…

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  8. You. Are. amazing.

    I had to tell you that your “must draw in five minutes” game comics…. still amazing stuff.

    Best wishes. Anyway, if you scribble anything on a napkin, probably still works of genius.

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  9. Good luck with everything. Random voices on the internet think you are pretty cool.

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  10. If there is such a thing as karma, you deserve a happy ending. You have provided so many happy moments to people you will never meet. Thank you and good luck during this difficult time
    Cheers
    a Fan

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  13. I enjoy your comic everyday because of the lift it gives me. My thoughts are with you and your family and I hope that someone is there to give you a boost in the same way you do for your fans. Hang in there.

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  16. Just wanted to pass on best wishes 🙂 xkcd is one of the things that makes me smile when my days start out horrible. Don’t know if it means anything, but I will pass up a prayer for your family as well.

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  18. May your family experience a refu-a shelayma, a complete cure of body and spirit.

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  19. Hey man the 5 min comics could have all served as their own comics, they were funny as Hell.

    If you are going through a really rough spot i hope everything gets better and if you need to stop to recuperate for a little that totally makes sense. Good Luck!

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  20. You’ve made me laugh so many times. May you and your family recover soon. Best wishes!

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  25. I’m keeping you and your family in my prayers, and hope your skies brighten soon. Thanks for all your hard work. As an animator I don’t always get all the jokes, but the ones I do understand are terrific.
    -JKR

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  27. Hugs, flowers, and prayers for you. I’m so sorry to hear things are rough.

    You bring a lot of joy to a lot of people, and we’re all wishing you and your family the very best. ~

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  28. Just wanted to say that I really enjoy your work, and thanks for taking the time to put up those five-minute comics. I wish you the best to you and your family.

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  29. I have a blast every week reading XKCD, and it brightens my day and they day of everyone I know. Thanks for making the internet a brighter and more interesting place.

    I know life is probably pretty shit right now but I wish you and your family the best. Take time off and do what you need to do and we will be here routing for you when you get back.

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  30. I’d like to add my best wishes and hopes for a happy outcome for you and yours.

    And to add my bit to your collection of Fan mail. Excellent comics, all of them. I still have a bit of a giggle about Bobbie Tables from time to time :).

    Thankyou.
    Steve.

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  31. These five-minute comics are way better than your regular stuff. When you return to a regular schedule (best wishes for whoever’s sick), you should write more stuff like that.

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  36. I hope your fellow submariners (or submariner support staff) recover from their health conditions quickly, with as few complications as possible, and emerge even stronger from the experience.

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  37. Best wishes for you and your family – I hope you’ll get rid of that illness soon!
    Amazing article, loved the description and the concept. Thanks for sharing it with us!

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  38. Wishing you and your family well and a speedy recovery both physical and emotional.

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  46. Hey,
    so sorry to hear about the illness. I really hope everyone’s going to be fine.
    I wish you a lot of luck and courage and send you all the good vibes I can.
    I don’t know how far they can travel, ’cause I’m in France but you’re the physicist so you’ll know.

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  47. You are in the thoughts and prayers of so very many. Thank you for the joy you bring us. May you have the ability to find rest and wellness soon.

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