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. Take care of your family first. We appreciate the creativity that you share with us, and we’ll be here to enjoy it whenever you have some to spare, but you’ve got your priorities straight. For what it’s worth, this sort of thing comes to every family as everyone ages and the older generation gets older . . . or not. (Yes, that was a joke about a very serious subject, because if I hadn’t been able to joke about it at the time I would have been crying a lot.)

    Best wishes, and may whatever comes to pass be for the best.

    Like

  3. Good thoughts going out to you. My Mom just passed away after a year-long battle with metastatic cancer so I know EXACTLY what you’re going through.

    Take care of you, take care of your family.

    Like

  4. Hey Randall,

    Just to add to everybody else’s comments, this comic has given me a lot of laughs in the time I’ve been reading and always brightens my week. Hope everything works out OK, there’s a lot of love for you floating around 🙂

    Take care,

    Andy.

    Like

  5. I recently had an illness in my family as well, and I certainly know how difficult it is to deal with other things when all you can think about is how your family member is doing. You and your family are in my thoughts and prayers. HUGS.

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  7. Keeping you and yours in my thoughts and sending my bestest Get Well vibes from Austin, Texas 🙂 Please don’t *ever* feel pressure to post on our behalf…just happy to enjoy your work when the muse strikes you! BTW, I’ve learned so much from researching your references…you make math fun! Long live math 🙂

    Best Always,
    Jana xo

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  9. All the best- I hope you and your family come through this. We all have you in our thoughts…

    Like

  10. If I may, on behalf of all your adoring fans from Chennai, India, best wishes and happy healing magical thoughts 🙂
    And also YOU ARE AWESOME. Just thought I’d say that.
    Much love!

    Like

  11. You comics are brilliant, and my m/w/f’s are always better for reading them.

    Sorry to hear about your family troubles. To reiterate what Jenny said:

    “Wishing you and your loved ones peace and strength.”

    Like

  12. My sympathies to you. I wish everything goes well or at least as good as possible, given the circumstances.

    Like

  13. Good luck to you Randall. I know the strain an illness can put on any family. You’ll be in my thoughts and prayers.

    Ryan from St. Louis

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  16. Best wishes to you and your family. You’ve got a whole lot of virtual shoulders to lean on out here.

    Like

  17. Good job getting people to suck your dick, Randy…

    …At least someone finally did! ZING!!!

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  18. I read your comics every M/W/F, have been for the past couple of years. I read the comic this morning, and I send my sympathy and support, having just gone through a very similar situation. I’m glad to hear whatever is going on will be okay, but you and your family will be in my thoughts every time I come to visit this site ❤

    Like

  21. Best wishes to you & yours bud, reading your comic is a regular ritual and is something I look forward to a great deal.

    RE the ROV, an improvement on what looks to be the Arctic Ethernet cable you’re using there may well be to get hold of some ProPlex Ethernet cable. Is is more expensive, but is proven in both freshwater & marine environments.

    PUT jacket, Kevlar inner, Mylar and braided shields, and is available in either UTP or SFTP. Was designed for rock & roll touring but is now being used to tether sonar arrays and by the Canadian military as a standard hard as nails Ethernet cable.

    Only downsides are that the shield and Kevlar inner make it a little trickier to wire and that an eccentricity of the manufacturing process (apparently) means that the striped wires of each pair don’t actually have a stripe; they’re just white. Not an issue if you’re careful when wiring.

    Manufacturer is a company called TMB (www.tmb.com). If you speak to Jedd or Linda in their NY office, they’ll be able to put you on to a place you can get it locally.

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  22. Best wishes for you & your family, as much as we love xkcd we understand and hope you don’t try to do more than you can. Take care!

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  23. Hi. I’ve been reading your comic for a long, long time. I don’t know how long exactly, but it’s been a long time. I’d say about a year ago I went through your entire archive and since then I’ve caught every new comic.

    I love your comic, it is usually one of the brighter parts of my day when a new one comes out. I especially like the romantic ones.

    Anyway, I doubt you’ll read this, since there’s already more than two hundred comments on this post and you’re so busy with real life, but I wanted to offer my hope that the illness won’t be so bad. I’ve been dealing with the illness of a friend and neighbor. I’ve been bringing her and her husband food every day because she’s on chemo and can’t cook for herself and her hubby works all day.

    I have nothing but love for you. Thanks for making my days just a little bit better.

    Like

  24. Sending a virtual hug and kindling a virtual candle for you and your family. Wish you lot of love and strength in the difficult times

    Like

  25. Randall,

    I will mention you to my geeky family as we all enjoy your wonderful little comic, since I bought my wife a ‘sudo make me a sandwich’ tshirt. You will be in our thoughts.

    Like

  30. Your comics always make me smile. That’s not intended in any way as pressure, just a thank you.

    I’m sending all that joy, and healing thoughts, back to you and your family.

    Like

  31. When people who bring so much joy to others are subjected to hardships, it makes the world seem that much smaller. We’re all in this together. All the best from Louisiana.

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  32. Just wanted to send along some good vibes from way up in Ottawa! Take time out for yourself and your loved ones; we can always go through the back catalogue if we are in need of a good chuckle.

    Best wishes!

    Like

  33. I hope you and your family are surrounded by wonderful caretakers and the coming months bring good health and lots of joy to all of you. XKCD is a hilarious and sanity-supporting bright spot in my life, so I will wait patiently even if you need to take months of time completely away from your public efforts. It’s far more important for you to take care of yourself and your family!

    Like

  36. I understand you probably won’t read this, but I hope just the number of comments alone bring some light into a dark time. You’ve certainly brought light into my M/W/F’s and many smiles to my face. When work’s especially tough, knowing it’s an xkcd day makes things better.

    Blessings to you and yours.

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  38. Sorry to hear you’re going through a rough patch in life right now. Don’t worry about your web audience; do what you need to do to get through it, and keep yourself strong for yourself and your loved ones, including the one who is ill. Take care!

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  39. All the best for you and your family. I’ve been a fan since #90 and I haven’t stopped since then. I have faith that you and your family will overcame whatever hurdle that should come your way, and I can assure you that your huge online family will be here for you!

    God bless you and your family.

    Like

  41. Best wishes to you in this trying time. In honor of one of my favorite comic of yours, I’d like to give you a big ass-hug.

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  43. I am very sorry your family is going through a rough time. Your comics are something I look forward to every M/W/F and that makes you a part of my everyday activities, so I have become appreciative of your ingenuity and I wish to offer you and your family my sympathies and best wishes.

    Like

  44. Long time reader, first time poster. You’re an awesome guy with a brilliant sense of humour and if there were any justice in the world, you wouldn’t have to worry about things like this 😦

    My best wishes

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  45. Your comics have brought a lot of joy to a lot of people. If the medical challenges you are facing now are causing financial challenges for your family, please put up a donate button somewhere so we can reciprocate for all the humor and goodness you’ve brought into our lives by helping out in a tough time in yours.

    Best wishes for you and your family. I’ve dealt with some serious medical challenges in my family (years worth) and know just how intense and how draining the emotional roller coaster can be.

    peace

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  46. Best wishes to you and your family. Thank you for xkcd which is loved and respected. Take care.

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  47. I had to deal with a serious family illness earlier this year, so I have some idea of what you’re going through. I hope that medical science helps your loved one as much as it did mine.

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  50. I’m very sorry to hear about the illness in your family. Thank you, my whole team at work loves reading xkcd.

    Do what you need to do to take care of you and your loved ones. If that means missing the comics for a while, so be it — we’ll be here when you get back. 🙂

    Like

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