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, you’re a legend! But even legends need some down time so take it easy, do what you need to and come back strong! Best Wishes.

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  2. Hi Randal, you’re a pure genius and that makes me even more sad about the problems you’re facing right now. I hope you all the luck you might need and I sincerely hope this period will soon be over with a positive outcome!

    Like

  4. Thank you so much for all your accessible, identifiable and honest work thus far. I wish you and your family the best and know that many of us will be praying for you all through this time. God bless you guys.

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  5. There is no need to stress about us so please take your time dealing with your situation. I love your comics because it brings joy to a rough day. I wish the best of luck to you and your loved ones. I hope everything works out for you and your family. ❤

    Like

  7. Your comic brings a happy moment into the lives of thousands of people worldwide. I’m sure we all wish the best for you, and stepping out of my speaking for others role, I know I do.

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  8. Hey, I just saw the cartoon today and I wanted to wish you all the best. I know how hard it can be when the really serious stuff is happening. I don’t read the blag/news much, so thanks for posting this; you really add to life with XKCD in significant important way; we, me, my partner, my friends, talk about and sometimes investigate things you have posted on here. In this way XKCD is an education. Heck I’ve even used it educationally because sometimes you’re so right that there is no better way of putting it.

    So, as other posts have said, take all the time you need. I’ll still be checking XKCD every day, and we’ll all want to know how you’re going, because we care.

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  9. Hi,
    first of all: take care, hope everyting will turn ok. So, don’t push you too hard and keep focused on important things.
    I always read you with pleasure.

    Best regards from Italy

    Ruggero

    Like

  11. Good like facing the raptors – I hope everything works out OK for you and your folks.

    I’m sure we’ll all still be here when you’re ready to return 🙂

    Best wishes,

    Dan

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  13. mr. randall-

    i hope everything works out for you and your family. i know hundreds of people are probably telling you this right now, but it’s as true for me as it is for everyone else. you and xkcd represent a spot of humor every mwf that simply can’t be replaced by anything else, but your personal well-being is paramount. take care of yourself and everything, and wish you the best of luck!

    ~soren

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  15. As someone who just went through a protracted family illness, you have my sympathy. I hope it ends up okay.

    On a more frivolous note, I have that same joystick. Good choice.

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  20. I’m sorry to hear about your family, Randall. As with everyone following your comics, I wish your loved ones swift recoveries and hope this will only be a minor bump in the course of your life in retrospect.

    All good wishes from Turkey.

    Like

  21. Hi Randall,

    Wishing you plenty of luck to get you through these tough times.
    In the meantime, I have years’ worth of XKCD archives to re-read 🙂

    Thanks.
    Anc.

    Like

  22. My thoughts are with you and your family – good luck getting through these bad times and as others have said, don’t worry about us here in cyberspace, just focus on your family!
    Helen

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  23. Best wishes from Switzerland for you and your family
    I’ll stay tuned and hope to hear from you soon.

    Michael

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  25. I wish u strength in these times! I hope that everything is going to be fine. We will wait for you here.

    MV

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  26. I wish you and your family all the best.

    Visiting your site has become a regular part of my days and I feel with you. I am waiting patiently and hope everything will become well.

    Andreas

    Like

  28. pls take your time..family is always more importend then anything else.

    xkcd become a importend part of my life and you make me smile so often, now it is on me to give something back. So I will waiting patiently.

    Best wishes to your family and you ..

    treknor

    *sry. for eventually grammar and syntax issues … *

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  29. I’m very sorry to hear about your family problems. Will be thinking of you at least every Monday, Wednesday and Friday when the site comes up in my Morning Coffee!

    All the best to all of you –

    Damien (York, England)

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  30. I’ve been a big fan of your comic for years but never wrote.
    I just wanted to wish you good luck and thank you for your amazing work.

    All the best for you and your family

    Didac (Lleida, Catalunya)

    Like

  34. Hi Randall

    I was really sorry to hear about your family health problems at the moment. I hope it all works out, don’t worry about xkcd, all your readers will still love you when everything gets back to normal for you, take your time! 🙂

    Best wishes!

    Like

  35. Hey, take care, okay? Your (family’s) health > the comics.
    Though they’re pretty goddamn awesome and all. They even taught me some mathematical and scientific stuff, and I normally hate maths with a passion.
    So, I’ll be thinking about you.
    Best wishes from Belgium!

    Like

  36. i hope everything goes well and isn’t too hard to deal with.
    my thoughts are with you and your family.

    love your comic, btw 🙂

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  37. You really should cut your cable ties cleanly.
    These remaining spikes can be sharp like a razorblade and will hit the inner side of your hand/fingers with great precision … where it’s really annoying and painful.

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  38. Hi Randall,

    Take as much time as you need to. I’ve been a regular on xkcd for two or three years. Take as long as you need, and know that you have all of our full support. I’ll start looking for some mindless flash games to send to you.

    Just so you know, you are probably the person that catalyzed my switching to Linux and use of FOSS.

    We, your fans, will help you in whatever way you need.

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  39. Reading xkcd has given me a much-needed smile many times over the past two years when I’ve been dealing with my husband’s illness. Thank you, and I wish you and your family health and happiness in the coming months.

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  40. Hi Randall. Take care of your loved ones and don’t forget to take care of yourself while you’re at it. Xkcd has been a must-visit every m/w/f (and will continue to be so) and helped me heal. I’m grateful that you have so much to share. I wish you and your family all the best.

    /Jocke.

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  41. Best of wishes to you and your family. I’m sure everyone here more than understands that some things take priority over other things..

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  42. Hi Randal,
    I’m really sorry about your family problems. Best of luck to you and your loved ones, and thanks for your comics, which are officially part of my breakfast.

    Like

  43. Best of luck with all the health issue – and don’t worry we can survive looking at the old xkcd cartoons for a while 😉

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  44. Sorry to hear about your family illness, and best wishes for a speedy recovery! There are lots of old drawings for me to wade through, so take your time and concentrate on what truly matters.

    Like

  46. People have said it all, but here goes: all the best to you and your family, and don’t worry too much about updating. Draw if you feel like it, it’s great for taking you mind off things for a while if you feel like it 🙂

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  47. Just one more reader wishing you and your family the best in getting through a difficult time. Take care.

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  48. i will be praying for you and your family. its very tough to deal with, i know.

    and your underwater exploration gear looks very neat.

    Like

  50. Sorry to hear about the health difficulties, hope everything works out for the best.

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