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:
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:
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.
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
At the bottom of Walden, there are close to three extra atmospheres of pressure.
The zip ties double as binary depth markers. This one is 14 meters.
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.
xkcd 
I love your work, and your ROV is pretty cool too! I hope that all that is wrong in your world rights itself in the near future, and that all of your love ones who are ill right now regain their health. Warm thoughts are heading your way…
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I hope everything turns out alright, sir. I love your work a whole, whole lot, and am sending good thoughts your way. Having an ill family member is one of the most gut-churningly terrifying things that can happen to a person. Thank you for making my own rough spots just a little bit smoother.
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Sorry to hear about your current troubles. As a very new follower of the webcomic (introduced to it by my son) and despite my liberal arts background, I have become a ‘fan’ very quickly, and have been enjoying going back over issues for the last year. I especially liked the map of the internet, and comparing it to the older one.
My best wishes for you and your family, healthwise and in every other way.
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Hey, just wanted to add a quick comment and say that I’m hoping for the best. xkcd has certainly cheered _me_ up a few times when I was having a rough time.
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I’m a huge fan of your work, and I look forward to when you’re able to return to making more. In the meantime, I hope that all goes well for you and your loved one.
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I was thinking about having an underwater Quad copter would be cool recently but, but i thought it will be too expansive. I will try to build such a 250$ Kit, thx for the Infos. I Gould be interestee in the Ethernet upgrade, too
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Best wishes for You and your family.
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Hoping all goes well for you all.
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I really wish you all the best in this; really hoping that everything goes right and you can quickly come back gifting us with the best webcomic ever.
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Randall,
Very sorry to hear of your family health issues. I wish you and your family all the best.
XKCD makes my life better – thanks for creating it.
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Randall,
You do what you need to do. I guarantee we’ll be here when you get back.
Don
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I send my best wishes and hope everything goes well. Thank you very much for XKCD, it makes life better.
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*hugs*
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I love your comic–it always brings a smile to my face. I am sorry to hear about your family. I hope everything works out okay. Best wishes.
EJS
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Three times a week you make my day brighter (I’m in Israel and we have a lot of sun here – so that really says something – at least I mean it to say). Since hardly anyone around me knows enough (physics & tech & math) to enjoy it with me, I keep this little piece of sunshine to myself.
Hope your days will be brighter and lighter soon.
Best wishes.
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I’m an English professor and fiction writer partnered to a mathematician, so you can imagine just how pertinent your comic is to my life. It’s brought me a lot of joy over the years, and my office door is liberally plastered with XKCD comics. Best wishes in the coming months.
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Wow. I hope that everyone in your family comes through okay.
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Best wishes for a speedy recovery. We’ll be right here waiting when you get back!
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I am a big fan of the xkcd webcomic, thank you for brightening up my Mondays, Wednesdays and Fridays with humour, insight, geekiness.and occasional spooky accuracy.
I hope that your family health problems are soon resolved and that everything works out for the best.
Best wishes
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So often through the last few very rough years for me, your comic has mirrored my mood, elevated my spirit, and given me oddly specific insight. I don’t know how you do what you do but you do and I thank you. Now that you are faced with some life-crap it is my greatest hope that some of all that good karma you’ve been broadcasting finds its way back to you.
Advice given to me while facing death I’ll give you – keep breathing.
Love works.
nil desperandum,
uba
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Best wishes! Hope everybody is okay soon again.
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I hope the bad times end soon for you and your family. You are a wonderful person and I am sure you will find courage to get past the tough times.
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Best wishes to you and yours, Randall. Hope your family member gets well soon.
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if you ever need it, do put up a donate/buy button for us, and we’ll throw money at you.
restorative places:
mount auburn cemetery (don’t forget the lookout tower), the lookout atop prospect hill in somerville, the arboretums, little ponds closer by, like spy pond in arlington.
comforting foods:
watertown deluxe town diner, neighborhood cafe in union square, mac+cheese at publick house.
all the best from some local, long time listeners – first time callers.
❤
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Wishing you a speedy recovery. You’ve sent a lot of sunshine into the lives of others. It should come back to you now.
BTW, how does your binary depth marker work? Unless you’re using a different color for 1, those 3 black and 1 white would represent 15, not 14 (2 + 4 + 8 = 14; if white = 1, then it’s 15). No biggie.
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Best wishes, I’m in the same situation. Everything will be ok. It just has to be ok.
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You gave me so many happy and fun moments, that i feel i should send you some words. Keep beeing strong, keep smiling, and find support in your friends and family. I have been on the same situation you now are, só i hope my words are not empty. Your family kneeds you more than we do. No mather what we will be here waiting and hopping for you.
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Just want to pass along my good thoughts too and to let you know that even though we don’t know each other, the power of the Internet allows me to send all the spare mojo I have to your family.
Best wishes to you all.
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❤ from Aus, I hope everything turns out okay.
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Sorry to hear about the illness – will miss your cartoons during this difficult time!
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Hi, just sending some good wishes over from Europe, you have cheered me up so many times already, I really hope, everything turns out okay for you.
All the best,
Jane
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(((hugs)))
I hope everything will be ok for you and your family. Love all your work
🙂 x
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Hey there Randall – I’m finding out late myself, but wanted to pass on my wishes of support. I know how hard these kind of times are, and I feel for you.
Focus on what’s important: your family.
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Hey Randall, just saw your comic and wanted to send all my best wishes to you and your family. I love your work and your sense of humour and I hope things turn out okay. All the best!
(could not post this comment the first time due to the fact that I misread the reCAPTCHA word… what the heck is a Larclun?!)
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Hey, Randall, very sorry to hear about the illness, and best wishes for a good strong recovery. And some rest and peace of mind for all of you who are helping. Don’t worry about the blog, or about the comic, for that matter. If you want guest bloggers to fill in, just say the word, we’ll be glad to help out.
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I hope everything turns out ok, I won’t pretend to commiserate because I just can’t know what you’re going through, but I’ll be thinking of you.
I’d also like to add, you use meters! ❤ This brings joy to my heart. Spread the metric word to your countrymen!
Oh and Doh-San, I'm pretty sure a black cable tie is a 1, and a white one is a 0, so that's 1110, or 14 in base 10 – without the white one, you'd just have 111, which would be 7.
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Hey! I’ve been a fan for a long time, and saw your current comic up and thought I’d join the throng of sentiment. 🙂 Best wishes and thoughts with you — take it easy and do whatever you need to do.
Your ROV looks fabulous — I’m super impressed!
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Just going to repeat what’s been said so many times before. Your sense of humor that you share with us keeps me going through the week. Best wishes.
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many <3's & good thoughts for you.
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❤
Good luck to your whole family. You have an entire nerd populous rooting for a speedy recovery.
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Very sorry to hear about the illness, and all the best wishes for you and your family.
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I love your work – thank you so much for all the cheer and understanding I’ve found here (especially in hard times) over the years.
I was in China when my sister had a grand mal seisure (at 19) and started seeing neurologist – I (my whole family) had no idea what could be wrong at first! It was terrifying. It turned out to be epilepsy, and luckily not MS on top of it. But I remember sitting in a dingy hostel basement cafe wondering if she had a brain tumor and trying to change my plane ticket…. and then reading xkcd comics for hours.
Hang in there!
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Hope your family will get through it okay, sir.
Maybe a smile a day won’t keep the doctors away, but it will make somebody’s day, well, in victorian english sense of the word which means joy or cheerful, gay.
So here’s a smile for you lot =D
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Hope everything turns out alright!
You manage to make many people’s days (that were previously unbearable) bearable with your comics however random they are. You of all people know that many are hoping for the best for you and your family, you make coffee breaks thoroughly enjoyable, and that ROV is awesome o.o
Continue thy awesomeness!
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If it makes you feel better, the comic (comics?) you just posted made me laugh. If only for the bizzare, WTF?-ness of them, but they still had that XKCD-ness in them. Hope everything works out for you.
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Randall,
From a fellow CNU alum–I hope everything works out. xkcd has made my life better (except when I click “random” the night before a dynamics exam and find myself on your site for a few hours), and I’m hoping all these comments make you feel as good as we all have throughout the years.
Hoping for the best, and you’re in my thoughts and prayers brother.
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I’m so sorry to hear about your family misfortune. I LOVE XKCD, the comics always provide an uplift to my week. I’ll keep you and your family in my prayers ♥
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That’s terrible news, Randall. I’m sure everything will work out okay. Take care of your loved ones and especially yourself. Hope things get better soon!
cheers,
Gaurav
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