Underwater ROV with Basic Stamp Homework Board

stx2006

I have a Basic Stamp Homework Board and I'm wanting to build a underwater ROV with it. I was wanting to see if anyone could help me with the code? I'm new to coding and I'm so lost it's not even funny!

Ken Gracey

I think that building the ROV will be a bigger challenge - have you already done that?

Using DC motors for propulsion? Wired tether to a pushbutton control system?

Show us your project.

Ken Gracey

WBA Consulting

Welcome to the forums! Couple comments for you:

• What is your level of experience with the Stamp? Have you worked through any projects with the Homework board?
• What sort of ROV do you have any mind? Autonomous, wireless, or tethered?
• Have you checked through project sites for small ROV ideas? (like these on Instructables)
• Take a look at this thread about the Naval Academy's Sea Perch ROV kit/program. Got to the Sea Perch website and download the "Build" PDF for good ideas on how to make a small ROV easy and cheap. The full Sea Perch kit is $169, but you can order one without a battery for $134 if you have another 12volt source.
• What depth are you after?

I am working on plans for an underwater ROV for my daughter to use during a 2nd grade science project next month. (she can't wait) My goal is a tethered ROV capable of 15 feet, with a video feed back to the surface. I will be using 25 feet of bulk USB cable for the tether. We will be making the ROV out of PVC pipe, fittings, and ends. I have some outrunner motors that can be submersed for propulsion, although they are pretty big. The ROV will have a small control board that will use the data stream from remote to drive. I have a few different cameras to choose from, but an old Sony 2 megapixel Cybershot will probably be used as a safety measure (if it is damaged, I won't cry). I will have a local battery source since with the motors I have, I believe current draw could be an issue through the USB cable. Her "missions" will be conducted at Camp Far West, about 35 minutes north of Parallax.

stx2006

I haven't yet built the ROV. I have my plans made up. Just need to get it started. It will be made out of PVC. I'm up in the air on if I want it to be Wired tether to a computer or just push button. The ROV will be small enough to fit in a backpack since it will be used for research in deep caves.

And yes I have been on Instructables like crazy looking at the ROV's on there. I have some ideas. But it seems no one ever post how to do their control box. I know how to do a simple push button system but I was wanting to go a little more into it with some sensors on the ROV to let me know depth and temp. It will also have a 1080p cam that will feed back to us at the controller. I found the cam I want to use

Also my experience with the board is well little. I did a few of the projects and was able to get it working. But when I read the code I didn't really understand what it was saying...

I was looking at the idea of this.

http://www.instructables.com/id/Underwater-ROV/

Just a lot smaller.. And yes I will be using DC motors.

LoopyByteloose

If you want a teathered ROV (has a long wire connected to it for control), the build is feasible.

The biggest challange by far is, "What to use for submersible DC motors?" These MUST NOT leak and still perform. Some people have claimed to have luck with DC motors from submersible sump pumps that are 12VDC and used to remove bilge water from pleasure boats while tied up at docks. Salt water use will damage electric devices much faster than fresh water. Deeper dives will cause leaks sooner than shallow dives. So testing and developement if fresh water and with shallow dives will save you money while you learn.

stx2006

I was thinking a tether is the way to go.

Ken Gracey

stx2006, what you describe could be done with a BS2. You'll probably have buttons on your handheld controller for thrusters. With some transistors between the I/O pins and the motors you'll be able to read banks of pushbuttons and turn motors on and off. MATE used the BS2 for this purpose for several years.

Ken Gracey

stx2006

How easy is that to program!

Ken Gracey

stx2006 wrote: »

How easy is that to program!

Well, reading banks of pushbuttons on a controller and activating DC motors through relays is a matter of scanning I/O inputs and activating outputs.

Several lines of code for those functions. Once you start adding speed control with potentiometers and LCD feedback it's still easy - will only become a problem when you want to do more than one thing at a time. Program flow something like this:

- scan pushbuttons store to memory
- scan pots, maybe on A/D converter or using R/C circuit, store values
- actuate motors
- do it again

Ken Gracey

LoopyByteloose

It is a great project to have the BS2 do the actual controller and RS485 do the communications for noise immunity over long wire twisted pair. You can build or buy an RS232 to RS485 to connect to your portable computer, and build one for the BS2. The chips are less than $1USD.

In that way, communications of hundreds of feet will work quite well. If you go the 'push button' route and try to send all the the motor switch over long wires, you will have a lot of wasted power in long-wire voltage drops.

stx2006

Here is the design I made. Just need to test motors to see what size I need to move it. Will need to add a few bigger pipes to make it neutrally buoyant.

macrobeak

stx2000, A few suggestions from someone who has experimented with underwater ROV's; 1) Making the ROV from PVC tubing is bulky and inefficient. I suggest a lightweight metal frame with floats as required. It is easy to mount thrusters to a metal frame and the elctronic modules can be enclosed in the floats with waterproof connections. 2) Use hobby brushless motors as thrusters. They work fine underwater for long periods of time and there are several ROV online forums to give you direction ; sample ; http://www.homebuiltrovs.com/rovforum/viewtopic.php?f=3&t=1271 I suggest hobby fan ducted modules for thrusters - they have a close coupled propeller, cowl and brushless motor for a cheap price. 3) There are many examples of circuits and programs on robotic online forums for controlling the brushless motor ESC's for your thrusters (they use the same control signal as robotic servos). You need a model car ESC with forward and reverse direction for your thrusters. 4) The underwater ROV can be easily configured for control by joysticks, once again look at the robotic forums. 5) The Parallax site can give you all you need for circuits, modules, components and coding support.

xanadu

Have you checked out OpenROV?

http://wiki.openrov.com/index.php/Assembly

They have a nicely refined parts list, I've been following it for a long time, at the least it is probably the cheapest and most effective ROV design out there.

LoopyByteloose

stx2006 wrote: »

Here is the design I made. Just need to test motors to see what size I need to move it. Will need to add a few bigger pipes to make it neutrally buoyant.

You can add plastic water bottles for more buoyancy (or plastic floats), just use plastic ties to the frame. It gets tricky to change buoyancy if you are using plastic pipe for all and everything. The bottles can easily be removed, or a bit of water put in them to tweak exactly what you need.

Too_Many_Tools

I have always liked this site...well done for an amateur effort.

http://www.homebuiltrovs.com/

They have a forum also.

Too_Many_Tools

macrobeak wrote: »

stx2000, A few suggestions from someone who has experimented with underwater ROV's; 1) Making the ROV from PVC tubing is bulky and inefficient. I suggest a lightweight metal frame with floats as required. It is easy to mount thrusters to a metal frame and the elctronic modules can be enclosed in the floats with waterproof connections. 2) Use hobby brushless motors as thrusters. They work fine underwater for long periods of time and there are several ROV online forums to give you direction ; sample ; http://www.homebuiltrovs.com/rovforum/viewtopic.php?f=3&t=1271 I suggest hobby fan ducted modules for thrusters - they have a close coupled propeller, cowl and brushless motor for a cheap price. 3) There are many examples of circuits and programs on robotic online forums for controlling the brushless motor ESC's for your thrusters (they use the same control signal as robotic servos). You need a model car ESC with forward and reverse direction for your thrusters. 4) The underwater ROV can be easily configured for control by joysticks, once again look at the robotic forums. 5) The Parallax site can give you all you need for circuits, modules, components and coding support.

Hmm...could you expand on your comment for discouraging PVC?

Metal dies quickly in salt water.

Most amateur ROVs are not meant for speed so drag on "bulky" PVC assemblies does not matter much.

macrobeak

"Hmm...could you expand on your comment for discouraging PVC?" Actually, my first ROV was also a PVC pipe fabrication. Loopy stated the problem with PVC piping framework very well " It gets tricky to change buoyancy if you are using plastic pipe for all and everything." I found a metal frame with floats was much easier to achieve balance and bouyancy, and it was easier to attach thrusters, cameras and so on. As you add more equipment, just adjust the floats. The floats can be used and waterproof enclosures for control modules with waterproof connections. If corrosion is a problem, then use stainless steel, galvanised steel or aluminium for the metal frame.

LoopyByteloose

Yes, the center of buoyancy has to be higher than the center of gravity, and if you don't have the center buoyancy directly above the center of gravity exactly where you want it... the ROV will go there anyway..

Nonetheless, I don't think it is a huge mistake to start with PVC. You certainly don't have to use it for flotation. If it gives you a lot of imbalance problems, cut openings and let it fill with water.

If you really want to use it in sea water, be sure to wash everything with fresh water after a day of diving. Salt is going to get into any electrical connection with just an itty-bitty nick in the insulation. And metals are going to get eaten up. Epoxy paint over metal is a big help, but nothing is 100% and forever.

Too_Many_Tools

Loopy Byteloose wrote: »

Yes, the center of buoyancy has to be higher than the center of gravity, and if you don't have the center buoyancy directly above the center of gravity exactly where you want it... the ROV will go there anyway..

Nonetheless, I don't think it is a huge mistake to start with PVC. You certainly don't have to use it for flotation. If it gives you a lot of imbalance problems, cut openings and let it fill with water.

If you really want to use it in sea water, be sure to wash everything with fresh water after a day of diving. Salt is going to get into any electrical connection with just an itty-bitty nick in the insulation. And metals are going to get eaten up. Epoxy paint over metal is a big help, but nothing is 100% and forever.

I think you have touched on their problem..they were using it for floatation.

Any PVC that is not being used specifically as a float should be prepped so it allows water to enter and leave...it is simply a skeleton for other items to mount to.

Also having an open frame allows debris to become lodge and entangle the ROV..so many times a simple shroud is applied to the ROV.

FWIW...the search for Floght 370 has allowed the world to see the Bluefin up close..and to see some of the design choices the engineers have made.

Too_Many_Tools

FWIW..I have seen tiny homemade ROVs that run in an aquarium...with an option to remotely control by light...kind of fun chasing your goldfish around the sunken prirate ship.