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.
RE: http://xkcd.com/851_make_it_better/
I know I’ll probably have people hate on me for putting an infuriating Rihanna song in to everyone’s heads, but I think it needs some of this:
Oh Na
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No Getting Jiggy wit’ It?
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Hope the best 😉 Things will get better!
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Marshmallows in a vacuum=way entertaining.
Also, I wish you and your family well. I’ve been there, and you should take all the time you can to hang out and talk with your family, play games, and get drunk. Hope it gets better for you. x
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I fucking love you for the #841
Anyway. I hope all the best for you and your family.
G
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the time you can to hang out and talk with your family, play games, and get drunk.flapes sony brakson
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the time you can to hang out and talk with your family, play games, and get drunk. fortex
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ime you can to hang out and talk with your family, play games, and get drunk dress lokuy turabed
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n to hang out and talk with your family, play games, and get drun month fake as polices bob nonday
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n to hang out and talk with your family, play mop playes return gatern
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n to hang out and talk with your family, gabetag no shep clapert
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n to hang out and talk with your family, play games, and caparet young phata norse
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n to hang out and talk with your family, play short looking web your mend
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n to hang out and talk with your family, play games, and get drun derding in your lasy
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n to hang out and talk with your family, play gfeleyerd doble maney
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n to hang out and talk with your family, play games, february houtr
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n to hang out and talk with your family, play games, and get drun dfgdgfdgf
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n to hang out and talk with your family derdinang hotey fater
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n to hang out and talk with your family, play games, and get drun serat yuped vepead share well pop likes
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Hey hey hey!
Randall’s gay!
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perfect.. thanks from Turkey.. that is very good.
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rov is great
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wowww.. arduino guys.. 😎
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very nice this blog thanks admin
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I wish I could have been there to take part in this experiment
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thanks very nice blog!
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Why use ethernet? why not run USB over the ethernet cable and not have to deal with the shield. and you could run 2 (or more if you had a common power and ground) USB connection through it, allowing you to use a USB webcam!
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I was so sorry to hear what you were going through since November….and seeing your Monday April 4 comic – I wonder if things are better or how you’re coping up with the illness in your family. Your comic strip has made so many, many of us laugh through the years and have a sense of humor about life through our tough times, wishing you strength during yours.
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Does anyone know about how much coding one would have to be able to do to work that particular robot? also, how modifiable is that kit exactly? I can think of some cool design mods, but i have never written code before, and i dont want to get excited about something that will put me in way over my head…
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/’/…/…./…../ˉ
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……………………..’../
………………………./
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…….
Google in the input: = tntn.us ==you can find many brand names, even more surprising is that he will sell you the unexpected o(∩_∩)o
Hello,
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I love your ethernet-wired sub. You should add a live feed so you can give your catfish admirer a live video blog lol
What did you use for materials for this sub?
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Sie amk. I was so sorry to hear what you were going through since November….and seeing your Monday April 4 comic – I wonder if things are better or how you’re coping up with the illness in your family. Your comic strip has made so many, many of us laugh through the years and have a sense of humor about life through our tough times, wishing you strength during yours. vay ak.
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love your ethernet-wired sub. You should add a live feed so you can give your catfish admirer a live video blog lolthax
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Great Blog post. Thanks for taking the time to do it
Double Glazing Repairs
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Our Prayers and Thoughts are with you Randall
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The HQ/HD quality really shows well.
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Close this comic down Randall, it sucks these days- you aren’t fooling anyone anymore. I bet your girlfriend looks like a pizza that has been sat on.
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Wow!I really loved reading your blog. It was very well written and simple to understand. Unlike additional blogs I have read.
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Great Work
Interested in your coupling for removing the tether- pvc pipe fittings? Any chance you can elaborate on its construction?
Thanks
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Surely agree with simply what you said. Your explanation was certainly the simplest to comprehend.
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In my personal opinion is subject follow-up and congratulate you for the beautiful and hot topics at the same time
Only accept greetings
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Thank you very much.I like this site.
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Some biatch did this shizzle http://www.kickstarter.com/projects/openrov/openrov-the-open-source-underwater-robot?ref=NewsJul0512&utm_campaign=Jul05&utm_medium=email&utm_source=newsletter
drumrolll…..
the moment for-“DAMNIT, I SHOULD HAVE DONE THAT FIRST!” comes…….
.now.
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ay is, perhaps, the best western movie about Budhism.
He is born, lives and dies everyday, over and over untill ove
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SORRY to disagree with your assessment that WALDEN POND is DEAD. It is NOT. To prove this just put on a MASK and SNORKLE and FREE DIVE around the WALDEN POND. You will see: SNAPPING TURTLES, many different types of FISH (some stocked by MASS. Fish and GAME). KOI fish (obviously dumped into WALDEN POND). Etcetera. and see: http://www.mass.gov/eea/agencies/dcr/massparks/region-north/walden-pond-state-reservation.html
HAPPY SUBMERSIBLES !!
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Here’s a quick EXAMPLE of Non-Native FISH in WALDEN POND that someone (without a ROBOT SUB) photographed in WALDEN POND.
please see:
Walden Pond Koi
TheGizzard49 TheGizzard49·4 videos
Uploaded on May 19, 2010
Walden Pond Bass Fishing and Kayaking with Hobie Adventure Island and Sanyo Xacti CA9 waterproof camera
p.s. He used a SPECIAL Hobie Kayak.
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This is a wonderful article, Given so much info in it, These type of articles keeps the users interest in the website, and keep on sharing more … good luck.
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Thank you very much.I like this site.
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Excelente alternativa ya la puse a funcionar con el video y se maravillosa como siempre los mejores . Bendiciones
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