Need ROV Building Advice

Spot for your general beginner questions.
Zephyr
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Joined: Dec 5th, 2010, 1:41 am

Re: Need ROV Building Advice

Post by Zephyr »

Hey,

Doing MATE this year as well, good luck to you!

The cheapest and fastest way to get two arduinos is to just buy the ATMega32 chip alone with bootloader, and make your own arduino on stripboard, which is what we're doing. It's a lot simpler than you think. You might require a FTDI to USB cable though, if you don't have an existing arduino that you can reuse as a programmer.

And we're using marine 500gph bilge pumps, though those mayfair replacement catriges look cheaper. The only problem I can see if finding a propeller to fit, as we don't have lathes.

Good luck! Believe it or not, one of our member is actually using VB to code serial. Bleh. As long as it works, I guess.

The manipulator's having all of us wall-bangin'

Good luck!
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bigbellydude
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Re: Need ROV Building Advice

Post by bigbellydude »

Well, I am not sure what version of VB your team member is programming with, but if it is Visual Basic 2008 (9.0), you shouldn't have to worry about it. Contrary to popular belief, Visual Basic can handle just about all of the more complex algorithms and processes as C or C++, for example. I won't go into my "Life Without Walls" statement, though. :mrgreen:

I believe that one of our team members has an arduino that he used for something else. We might use it, although I am starting to think that for now we should stick with a relay circuit. Then all we would need to do is locate an "arcade type" joystick, which I believe to be the ones which do not have "free 3D" axis', but snap into 8 different positions: up, up-right, right, down-right, down, down-left, left, up-left. If I am not in reality about that, I stand corrected.

Coming Soon!!!! I will be creating an AutoCAD drawing of our proposed design, and posting it here. I should also let you know that if you are a student, you can get complete, full professional suites of almost all of Autodesk's software for free for up to 3 years! Otherwise, go out and win the lottery.

Sorry I rambled :oops: . I just got out of bed. Good luck in the contest! Josh
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bigbellydude
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Re: Need ROV Building Advice

Post by bigbellydude »

I forgot to mention that we'll probably (hopefully) not be using the Johnson Mayfair replacement cartridges. One of our team's member's dad used to work at West Marine, and he is going to try to get us 4 bilge pumps from them.


Just an update. Josh
Zephyr
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Joined: Dec 5th, 2010, 1:41 am

Re: Need ROV Building Advice

Post by Zephyr »

You lucky.... person.

Those bilge motors are the flipping most expensive bits of our ROV, not counting the motor controllers.

Well, he said VB... 6. He's somewhat old school, apparently. Oh well. It's looking halfway decent currently.

For now, we're going Computer - Arduino - 10 meters - Arduino(ROV). Frankly, the way this is going, the onshore arduino is acting nothing more than a relay.

Your relay circuit idea's fine, but i've got some qualms about that. We tried that last year, but with DPDT switches. The worst thing was trying to pick up something above the swimming pool, like that U ring. Or untwisting the valve. You'll have a heck of a time trying to stabalise the ROV at a certain depth without speed control.

But best of luck to you, regardless. Try an analog joystick out of a RC plane for easy controlling, as Arduinos have analog inputs. That's our original idea, and works great, but a USB joystick's cooler. Yes, we're kinda immature like that.
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bigbellydude
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Re: Need ROV Building Advice

Post by bigbellydude »

Well, as I keep looking at all of the info I have been collecting, I am glad that I am not the "Engineer", and just the Resources Manager! Whenever I think about the programming my teeth start chattering :lol: . My brother (also on team) thinks that he could do the programming OK, because he does have some experience with Python, but if we are actually going to have a computer control, I would need some VERY expert advice. I am sorry to say that I just can't seem to grasp the more complicated aspects of Visual Basic logic. I need to spend some more time on that though...

By the way, if you guys would like to be able to use a CAD software, you don't have to worry about expenses. Autodesk's AutoCAD costs brand new a whopping $1135!!! However, they have a really neat student software community, and you can get all of the professional paid-for versions of it for free with licenses for 3 years! Check out http://students.autodesk.com . This is where you can get the info for the drafting and 3D design software.

Josh
ckleppin
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Joined: Nov 20th, 2010, 2:33 pm

Re: Need ROV Building Advice

Post by ckleppin »

The after travel costs to get 5 people and gear to Hawaii last year, the motors were the most expensive part of the entire vehicle. We got 6 Seabotix motors which were not cheap, but they are pretty nice.

Also PWM motor control was pretty nice to have, although it took a fair bit of extra time to design the hardware to do it. Good experience since I am an EE.
Zephyr
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Re: Need ROV Building Advice

Post by Zephyr »

Whoop!

I finally finished the VB programming! It was, as you said, surprisingly easy. We now have a fully working USB control stick controlling a PWM wave form. Now to add the A3959 onto it. Oh, the nightmares.

How's your ROV going? I would love to post pictures of mine, but it's currently nothing but a lonesome chassis. That AutoCAD sounds great, but we don't exactly have the fabricating machine either. Or a lathe. Or a mill. I guess i'll stick with chalk and a blackboard.

Jesus christ, we're really under equipped, aren't we?

EDIT: Sorry, we're all sharing this account. He's somewhat hyper.
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bigbellydude
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Re: Need ROV Building Advice

Post by bigbellydude »

If you could give me some tips for the VB, I would really appreciate it.

As for AutoCAD, it is Computer Aided Design software, which means you can completely build your ROV on your computer first, then take the design and build it in real life. AutoCAD is used by inventors and architects for hundreds of different things, and I think it would be fun to do it for an ROV. Unfortunately none of the Autodesk software will work on my computer. I only have 384 Megs on mine, and the software pretty much all requires 2 GB of RAM. Oh well.

As soon as we get the frame built, I'll post some pics here. It isn't going to be very interesting, though. Just a rectangular PVC frame, with some packaging foam inside.

Also, if you haven't seen the mission prop photo's yet, you should take a good look at the first and second missions. A manipulator arm is a must, because otherwise there is no way anyone will be able to turn the knob and cap that thing, let alone remove the riser pipe. It's huge!

We have a new mentor! His name is Dan, and he is the mentor for the Aptos High team that won third in the Internationals last year. (Aptos is also just down the street) I will be relaying and info we get from him on this forum.

Get your engines started! It's coming up! Josh
Zephyr
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Joined: Dec 5th, 2010, 1:41 am

Re: Need ROV Building Advice

Post by Zephyr »

Yup.

We're still brainstorming on the manipulator. Currently, we're thinking of connecting a bilge motor to a clamp stand, so that'll ... probably.. work. The main limitations are the lack of the milling machines, or a CNC fabricator.

We actually have a pretty ingenous way to solve the valve problem. Connect a cross to the bilge motor, and stick it out of the ROV.

Sure, PM me with any questions, i'll love to help. Try specific ones though - i'm not writing the entire one for you :d
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sthone
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Re: Need ROV Building Advice

Post by sthone »

Here's a couple of examples of basic manipulators that work off the threaded rod principle. A motor (I like to use geared motors to slow things down) turns a threaded rod that is threaded into a block. As the rod spins it causes the block to moved back and forth which will in turn will force the fingers that are attached to the block to open and close. These examples where just original prototypes just to prove the design feasible. They were not made from materials strong enough to actually work.

You could do something similar using a harder plastic material (cutting boards are one of my favorite substitutes which is cheap and can be cut with bandsaws or even by hand.) You don't really need machine tools.

http://www.homebuiltrovs.com/stingermanipulator.html

Hope this gets you pointed in the right direction,

-Steve
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