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. Best wishes to both you and your family, Randall. It must be incredibly hard for you at the moment, but stay positive. I think I speak for all of us when I say that your extended family here on XKCD will all be thinking of you and your family, and we’ll still be here when you return.

    All the best, Vlad.

    PS: Nice ROV! =D

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  2. w=7e(s-L/3x)²

    I can’t pass on my wishes any other way. But as you can work out, it’s a lot.

    These words float across to you from the centre of England. Best of luck to you and all your family for these troublesome times, and I hope it all works out for the best.

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  3. Ditto, with all comments previously! I just had a similar rough patch myself over the summer. It sucked, but we got through it. Take all the time you need… we’ll still be here!

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  4. Wishing you all the best, all the way from Australia. Please post news of how this works out for you … when you can.

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  6. Hey, read your comic today, best wishes to you and your family from Berlin, Germany.

    I will include you and your family in my prayers.

    V.

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  9. God Bless and best wishes from Philadelphia. When we were going through a family illness your comics helped brighten my day even on the darkest of them. If I could repay you in some way I would. Suppose prayers will have to do for now. Thank you so much for your amazing sense of humor.
    -Jim

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  15. Wishing you the best through your tough times. Don’t worry about posting; we’ll still be here to read it when you get back. Focus on you and your loved ones.

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  16. You give everyone a lot of pleasure with these comics, even us liberal-arts majors. I hope things work out well and you feel supported by your appreciative readers.

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  18. From Singapore, I hope you and your family will be well. Thank you for an awesome webcomic, best of wishes to you and your family.

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  20. Sounds like you’re going through similar stuff I’ve dealt with over the last few years. Carer fatigue sucks. But XKCD is one of the things that’s made me laugh, think, and discover new things through it all, and I sincerely thank you for that.

    Strength and best wishes from Silicon Valley (well, almost) and be kind to yourself. Remember what they say about those air masks on planes; it’s better to make sure yours is on before helping other people. (This is especially true when there’s a drop in cabin pressure, since it makes the bloody things hard to catch! They don’t tell you that bit!)

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  21. XKCD is a regular part of my day, but somehow I never end up on this blog page. Thanks for posting today’s comic to let your readers know what’s up–and I join in the chorus of “we’ll miss you, be thinking good thoughts for your family, and hope all turns out as well as possible.” & like many others, I’ve been there, too, and can understand just how important it is to take this time for yourself and your family.

    Cheers / Angelique

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  23. Best wishes to you and your family for strength to get through this time and good health at the end!

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  24. Randall,

    Thanks for keeping it real with us. Don’t count out the possibility of working through your stress on paper; your art can be a tremendous outlet and as i’m sure you know, you may learn some things about yourself. You may find that this experience opens up new creative pathways and takes your art somewhere new. Your long term fans will enjoy whatever you have to share.

    Best wishes

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  26. I cannot believe this is happening to you… I’ve always imagined you living your life à la xkcd! I wish everything’s going to be all right again soon!
    Be strong, you have a **huge** amount of affectionate, though virtual, friends, whose affection’s real btw !

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  27. Another longtime reader and lurker wishing you well.

    And those binary depth markers rock!

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  30. Best wishes from Houston, Texas. Your comic has been a anticipated regular part of my life every MWF cycle, I’ll be slightly saddened by the lack of comics, but you’ve made me laugh and learn enough for years of karma points. Hope everything goes smoothly, and will work out.

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  32. So sorry to hear that. I’ve been there, it’s damn hard. Take all the time you need. All the best to you and your family.

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  33. Sorry to hear that you are dealing with personal issues right now.

    I just wanted to suggest that maybe it would help you to accept some guest strips from people during this time.

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  34. My whole (non-nerd) family has ended up hearing me (nerd) tell about your comics – every MWF. I was very sorry to hear you’re having a tough time with life. Take as long as you need… I’ll be waiting right here. Best wishes from Mississippi!

    P.S. Reading xkcd archives always helps me through a tough spot in my day. Maybe it would do the same for you…

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  36. While I have not posted before I have read every xkcd and I really appreciate the time you put into this as all of us do. I take time away from my morning at work every MWF to read the new ones and it always makes my day go better. Thank you for the work you do, hope things improve soon, and best wishes from MI.

    -Branodn

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  37. Sorry to hear about the illness. I’ve read every one of your comics; thanks for bringing math into online humor.

    I hope that your family get better soon.

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  39. Every MWF I love finding out what the new comic is. Sorry to hear about your rough patch, you are not alone. While I am also going through tough times, your comic keeps making me laugh.

    Thanks for all you do and best wishes from MN.

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  40. My whole family reads your comic, including my middle schooler. Our thoughts and prayers go out to your family and you. May you have strength, support, and solace, each when you need it most.

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  41. Everything falls off docks! Slap a high-field magnet on the bottom of that thing and you’ll pull up any amount of interesting stuff. As older things are more likely to have ferromagnetic material in them (less plastic, more steel) it may even serve as a filter to preferentially recover the deeper past.

    Other than that: take care of yourself and your family.

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  42. Take time for yourself above all. We appreciate you sharing your talents with us. Best wishes to your family. From another Slumerviller.

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  43. Local thoughts and good wishes from here in Boston. I’ll add to the voices that say: remember to take care of yourself so you can continue to take good care of others. Be well.

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  44. Best wishes from Scotland, our thoughts are with you.

    I’m delighted you are interested in ROVs, I am lucky enough to work with them for a living. If you need any tips, feel free to give me a shout. I’m quite interested in your Python code myself, I started on something similar a while back, but I’m too rusty now 😦

    Take care,

    Rovman

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  45. My very best wishes for healing of your family. I echo others’ comments: take care of you and yours first, and share when you want! I have so enjoyed your comics. Thanks for sharing them.

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  46. Well, you seem to have lots of best wishes comments, so here’s something different:

    Loved your ROV vid and story! You should add (when time allows) a remote grasping claw to the unit so you can pic up some of those lawn chairs! Though it may need more beefy motors to haul up the weight… Maybe instead, add a way to attached deflated balloons and include a tube from the surface to pump air down into the balloons to float things up, like with the Titanic!

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  47. I always look forward to new XKCD comics. You bring a little pleasure to my life each time.

    I am terribly sorry to hear about the difficulties. What an enormous stress it must be.

    Thank you for letting everyone know. I hope for the best possible outcome for you. Taking care of things like that trumps anything else. Do take care.

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  48. Best wishes for everyone’s health. I’ve never commented before, but read xkcd regularly. Take care of yourself and anything else you need to and know we’ll be waiting when you can resurface again.

    And, I’m an anonymous stranger on the internet, but if there comes a time when help from us would be a help, please ask. You have a reader base with a wide set of expertise, but you also probably have some readers who can manage a covered dish, a card, or anything else that might help. For now, I’ll try to pass my thoughts forward in your honor.

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  49. Take care of your family and come back when things are better. Sending lots of positive vibes your way.

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  50. Hey Randall,

    Sorry to hear about your family’s difficulties. I hope everything works out. Good luck in dealing with everything that comes your way in this time. And thanks for the comic; it’s amazing.

    Best wishes,

    Eoin (Ireland)

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