Underwater ROV

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Underwater ROVby SpaceShipOne on June 20, 2008

Table of Contents

Underwater ROV ..............................................................................................................

Intro: Underwater ROV ......................................................................................................

Step 1: Design ............................................................................................................

Step 2: Frame .............................................................................................................

Step 3: Thrusters ..........................................................................................................

Step 4: Navigation ..........................................................................................................

Step 5: Camera ............................................................................................................

Step 6: Lights .............................................................................................................

Step 7: Control: ROV side ....................................................................................................

Step 8: Power ............................................................................................................. 1

Step 9: Control: Surface ..................................................................................................... 1

Step 10: Tether ............................................................................................................ 1

Step 11: Testing ........................................................................................................... 1

Related Instructables ........................................................................................................ 1

Comments ................................................................................................................ 1

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Intro: Underwater ROVThis instructable will show you the process of building a fully functional ROV capable of 60ft or more. I built this ROV with the help of my dad and several other peoplewho have built ROVs before. This was a long project that took al summer and part of the beginning of the school year.

Step 1:DesignIn order to keep the ROV stable in the water, you need a design that is weighted on the bottom and has floats on the top.

The first ROV was built by Steve of Homebuilt ROVs . His website has numerous ROV designs as well as links to other ROV websites. He also incorporates several HTo instructions in his site. I found this site to be invaluable in building my ROV, and would recommend it to anyone interested in building their own

The second ROV was built be Jason Rollette at Rollette.com His design is a little different but still very effective.

For my ROV I decided on a large center tube with two smaller tube located on either side, slightly underneath the center tube.

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Step 2:FrameHere is the beginning of the f rame I am building for the ROV. I cut plexiglas windows and sanded them to fit inside the pipe. This is Schedule 40 ABS pipe, commonlyused for sewage. When joining this pipe, make sure you use solvent glue that is specifically made for gluing ABS. Normal PVC cement will not work or create a poor bthat could leak. I am also using a marine sealant to seal the plexiglas and prevent water from coming in. On the back end, I am using screw plugs in case i need toaccess the batteries or electronics again. I will need to wrap the threads in teflon tape to make it water tight.

After some testing, I found that the screw plugs leak, so I switched over to rubber end caps that have a band clamp to secure them.

Image Notes1. These are the plexiglas view panes. I haven't glued them in yet2. Protective film

Image Notes1. Completed pod loaded with battery.2. Thru-hull hose connector to watertight the wires3. Power cables4. light cables

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Image Notes1. Sch 40 1/2 in. PVC

Image Notes1. 5200 Marine sealant, available at Home Depot or West Marine

Image Notes1. Main housing in place and secured

Image Notes1. Detail of waterproofing thru-hull. Hoses will be filled with silicone caulk2. Power thru-hulls

Step 3:ThrustersOne of the most important features of an ROV is movement. I found that most people use marine bilge pumps as a means of thrust. BIlge pumps have many advantagThey are meant to be submerged, they are fairly powerful and they are easy to add to an existing ROV. Most use them in their current configuration, but I opted to usepropellers to increase thrust. I followed the instructions at Homebuilt ROVs . In the How To sections, he has instructions on converting a bilge pump to use a prop. Thepropellers came from Harbor Models , they have a good selection of plastic and some nice brass props, with many different sizes.

I used 4 Rule 1100 GPH bilge Pumps, 2 for forward, backward and turning, and 2 for up and down.

Step 1: Cut off all of the white housing of the bilge pump, but be careful not to cut into the red motor housing

Step 2: Use a screwdriver to pry off the impeller, the blue thing to expose the motor shaft.

Step 3: I use a prop adapter for an airplane to attach the propeller to the shaft. It has a set screw, and I just tightened the nut against the threaded hub on the prop to lit in position. I had to re-thread the prop adapter because it was a little too big. As a extra precaution, i used thread locker to seal the assembly together.

Since the threads did not line up, I was forced to re-tap the prop adapter. Although it seemed straightforward, it took considerable time to do it correctly.

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Image Notes1. The shaft has a flat spot, make sure it lines up with the set screw to providemaximum strength

Image Notes1. set screw

Image Notes1. 4mm nut used to lock prop on2. Finished product!

Step 4:NavigationTo determine which direction the ROV is facing, I used an electronic compass. This is a Dinsmore 1490 electronic compass. I got it from Zargos Robotics . I used thisschematic to create a visual representation of the direction. One note: This compass has no North. You just select a direction as north, and then all the rest will line upis also very sensitive to tilt, a few degrees and it gets screwed up. It senses changes in Earth's magnetic field, so make sure you place it far enough away from magnelike the ones in the motors. If you need more info about the compass, check this site out

In the picture, the four wires in the silver casing will go to the surface and interface with the computer to show me which direction I am facing. I am writing a program thwill rotate an image of the robot to show direction. However, this might take a while so for now I might just use the LEDs

For a tilt compensated compass, check out this one at Sparkfun. It is definitely top of the line, but also carries a huge price tag

EDIT: I removed this because of its inability to maintain a steady heading. This is most likely due to the tilt that the compass couldn't handle, along with the magnietininterference.

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Image Notes1. The arrow indicates the direction I chose as north2. Data cable3. LEDs give a visual representation of direction

Image Notes1. LEDs indicate direction2. antenna

Image Notes1. Indicator LEDs to confirm functionality

Step 5:CameraObviously you need a camera to be able to see what is going on, right? There are several different ways to go when getting a camera. If you're planning on going pretdeep, then a black and white infared camera would be a good bet. For shallower water, color works just as well, plus it shows more detail (ie. color?). If you really wangood picture, then go with a dedicated underwater camera. These cost quite a bit more, but you don't need to worry about an enclosure, and they often switch to night

vision automatically with built in IR illumination when there is not enough light.

I went with a 30$ color camera from Spark Fun. It has an RCA output that I will attach to my computer. Here it is attached to a mount ready to be installed.

The PC card connects to the camera via RCA, and also came with a program to view and capture the video feed

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Image Notes1. Lens cap is off2. stress relief3. jumper switches from PAL to NTSC outputs

Image Notes1. Courtesy of Ebay, PCMCIA card wi th RCA input

Step 6:LightsI needed some lights that are fairly bright and also efficient. LEDs are exactly that, and I found some at Spark Fun Electronics . I used two 3 watt LEDs, and to be honethey are blinding. They do get a bit toasty, so be sure to use a heat sink to prolong the life of the LED. Spark Fun sells an aluminum breakout board that has solder spfor wire and also acts as a heat sink. They have different LED colors too.

I attached the LEDs to a stand I made out of an L bracket to hold the in the center of the viewport. to make it easier to change, I bolted them to a aluminum strip so thathey an be adjusted or replaced

The pictures do not show how bright these things really are. After looking for a second at one, I had spots in my vision

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Image Notes

1. No, the Leds did not cost $ .25, rather they cost $7

Image Notes1. JB weld, a marvelous 2 part epoxy that glues almost anything

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Step 7:Control: ROV sideThis is probably the most difficult part of the entire building process. I have seen numerous different approaches to controlling the ROV. Jason Rollette used amicrocontroller, which is really the best way to go. He has full analog control of all motors, and at the data is transmitted up a Cat 5e Ethernet cable. However, unless have the means to print out a circuit board and program a microcontroller, this is not the easiest to assemble. Jason has a diagram of the circuit and the PCB on his sihere

Alternatively you could use relays to switch the motors on and off. this is not as good as full range control, but it is much simpler and straightforward. At Homebuilt RO

Steve used relays to control the Seafox, and he has a good guide to assembling any number of relay controlled motors.

This is one of the 4 speed controllers I am using for the thruster control

Image Notes1. Motor leads2. Power leads3. Control wire4. status and direction LEDs

Image Notes1. All 4 speed controllers. The three yellow ones I had to buy, the blue one camefrom a previous robot.

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Image Notes1. Thrusters speed control wires attached to reciever2. big cable mess

Step 8:PowerI decided to carry batteries in my ROV to make it more independent and reduce the number of cables going to the surface. This is one of two 12 volt 2.5 amp hourbatteries I bought from Battery Mart . I have already wired it up to a Deans Ultra connector so it can be easily removed if it is needed. Due to the amp draw of the

thrusters, I might need to incorporate a charging circuit to keep the batteries topped off. They will be carried in the two side tubes, and add much needed weight to theROV

Image Notes1. Sticker from Battery Mart!2. Female Deans connector

Step 9:Control: SurfaceNow we enter the difficult realm of piloting. The two people I talked to use a laptop to control their ROV, using a keypad or joystick to move the ROV around. This is grbecause all you need is the ROV, the control cable, and your laptop.

I wanted full analog control with out using a microcontroller, so I decided on ESCs, Electronic Speed Controllers. These should be familiar to everyone who has a modplane or car. I needed reversing speed controllers, and stumbled across some at Bane Bots . They are plugged into the Reciever inside the ROV, and the antenna isattached to one of the Cat 5 wires. From there I used my Hitec Remote control with the appropriate crystal and frequency.

The light are controlled by a switch that is operated by a servo. The compass has yet to be set up, but I think I might just use a bunch of LEDs instead of trying tointerface it with my laptop.

EDIT: I have since upgraded my control system using an Arduino microcontroller and a servo controller. I will post my results a soon as I finish sea trials.

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Image Notes1. My Hitec RC Transmitter, usually used for flying airplanes

Image Notes1. left over 4 channel receiver from another robot

Image Notes1. Water tight Pelican case

Image Notes1. BNC connector for Video2. CAT5 jack for tether

Step 10:TetherTo connect the ROV to the controller, I am using 100 feet of Cat 5e Ethernet cable. It has 8 wires, which fit in with my plans nicely. I might add a second cable if I havemore features I need to run, but for now it looks good.

This is plenum rated Cat 5, meaning that it can be pulled through walls using a fishtape. The covering is tightly shrunk and has a thin nylon cord inside that helpsdistribute the load over the entire cable. This makes it more durable and reduces that chance that I damage the cable from load stress.

I will need to add f loats to the cable because it will probably sink due to its weight.

The connector I used is a Bulgin Buccaneer Ethernet connector. I t makes it easier to transport the ROV by separating the cable and the robot. Bulgin tests their connethoroughly, and this is supposedly rated to 30ft for 2 weeks and 200ft for a few days. As I am planning on going no more that 100, this is well within the limits.

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Image Notes1. Wire spool I got for free

Image Notes1. other end is disconnected2. coupling ring

Image Notes1. compression fitting2. cat 5 joiner3. waterproof seal that fits into the compression fitting4. o-ring

Image Notes1. assembled watertight connector

Step 11:TestingThe first time the ROV saw water, I tested it in my uncle's pool. As was expected, the ROV was too buoyant. I have since added lead weights I purchased at a huntingstore to add weight to the skids. Lead shot would have been preferable because it is finer and easier to use, but it is really expensive. The lead also allows me to adjusthe ballast with a reasonable degree of precision in the event that I need to change the weight on the spot. The total required ballast was about 8 lbs, quite a load. Thenext test will be in another pool, and then its hopefully into a lake! If you plan on using this in salt water, it would not be a bad idea to rinse it off afterward to keepcorrosion down.

I will try to post some videos in the near future to show how this thing works in the water

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Image Notes1. All done, ready for the water

Image Notes1. Revised compass module attached

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Comments

50 comments Add Comment view all 175 commen

Legoman132 says: Feb 16, 2011. 3:34 PM REPI am building an ROV myself, and I was wondering ow far your lights penetrated in cloudy water. Also, I flound that the 1250 GPH bilge pump replacementcartridge from West Marine doesn't need cutting to get to the motor shaft, and I got some boat props from hobbytown that fit the shaft perfectly, just tightenthe key and go. The only issue is they produce more thrust in one direction than the other. Do you have the same issue? I also find that mounting yourmotors with PVC pipe clamps (in the 1 1/2 inch realm I think) and some old bicycle inner tube around the motors holds them on solidly, and you then putsome bolts through the frame PVC (assuming your frame isn't watertight). This forms a very solid mount(at least for me) that doesnt move. It also doesn'tcrush your pipe like pipe clamps do.

MR JAMES says: Oct 1, 2010. 8:05 PM REPcool i want 1 of these lol

ghostrider2 says: Jun 16, 2010. 4:05 AM REPhow much was the total cost of the project?

SpaceShipOne says: Jun 18, 2010. 8:59 PM REPabout 300$, depends on how complicated you make it

rajeev.piyare says: Jul 12, 2010. 9:09 PM REP

hi any idea if we can get the codes and circuit diagrams for this whole project so that we can implement as well please. Thanks

BJMN says: Feb 7, 2009. 2:05 PM REPI have a quick question - I remember learning in school that water is opaque to IR. My wife is a certified IR photo tech, and I know that our IR camera won'tshow things even just a few millimeters under the surface of water. Is it really IR that these cameras use?

SpaceShipOne says: Feb 7, 2009. 7:49 PM REPMy camera is not an IR camera, but Sparkfun carries a similar model in IR. I do know that most people use night vision cameras, similar to the types thcan be purchased form fishing stores. I have also heard of B&W cameras being used, since they are IR sensitive.

BJMN says: Feb 8, 2009. 8:44 PM REPHmm - just curiosity, since I don't doubt you've researched more than I! But to rephrase my question - since water is opaque to IR, wouldn't IRcameras be relatively useless underwater? If B&W cameras were IR sensitive, wouldn't they still just be picking up the visible light spectrum, sincewater emits an even IR level? Anyhow - not looking to troll this thread out - but still curious as to how an IR camera would function underwater!

rrrmanion says: Sep 3, 2009. 6:16 AM REPmaplin seem to be selling a camera that is apparently able to see up to 7m it has 12 IR LEDs, so it seems IR does work under-water so perhaphow you had it set up or something I don't know

wheelerjp50 says: Mar 26, 2010. 12:05 PM REPRed light can penetrate up to 15 meters in water. Most b&w cameras pick up near infrared that is between red and true infrared. So 7msounds reasonable. Like any light it would be limi ted by suspended particles in the water.

SpaceShipOne says: Feb 9, 2009. 10:33 PM REPI don't know for sure, but it could be that water is opaque to only certain wavelengths of IR.

nomejodaslavida says: Feb 28, 2010. 4:22 PM REPIf you're going to use the submersible bilge pumps as motors, why not use them as they are, without propellers, for jet propulsion? You could even increathe force of the jet by by graduating the discharge down to a smaller size.

quesoman says: Feb 22, 2010. 8:30 PM REPis a video of the ROV in action possible?

myfixitshowcom says: Feb 22, 2010. 8:02 PM REP"This is plenum rated Cat 5, meaning that it can be pulled through walls using a fishtape."...could be wrong, was couple times afore, but I think 'plenum' cable is cable which uses insulation that does not produce harmful vapors when burned. Insome commercial buildings, a/c return-air is run (without ducts) in the space between the room ceiling and the floor above it, ie the 'plenum'. If a fire everbroke out, this specially-designed 'plenum' cable would not release toxic fumes into the a/c system air f low which would injure or kill all living creatures withthe air conditioned space.Other than that, thanks for the info here. I have been working on my own system, mostly to get live pics in the canals here in S. Fla. My interest is in getting

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the 'real' closeups of the many 'gators that live here; maybe one day I'll get some neat shots as my mini-cam gets swallowed whole!myfixitshowcom

your dog says: Sep 28, 2009. 5:16 PM REPwould be a good camera?it also has infered so you would not have to buy lights

http://cgi.ebay.com/CCTV-Security-30-IR-LED-Waterproof-Camera-Power-Bracket_W0QQitemZ350211816960QQcmdZViewItem be a good camera?

astrong0 says: Feb 21, 2010. 3:20 PM REPYou spelled infra-red wrong

SpaceShipOne says: Sep 28, 2009. 8:21 PM REPYes, that camera would work for this application, however, you would need a housing because this camera is not rated for underwater use. The bestcameras are ones actually designated for underwater use.

your dog says: Sep 29, 2009. 4:20 PM REPit says it is waterproof in the title-

SpaceShipOne says: Sep 30, 2009. 3:34 PM REPYes but unless it specifically says it is submersible to a rated depth, I would not trust it. Waterproof simply means, if it rains, it will not getdamaged

jumpup_dnb_dj says: Oct 30, 2009. 12:31 AM REPI think you are actually making reference to water resistant not waterproof as you state here.

SpaceShipOne says: Oct 31, 2009. 2:42 AM REPI stand corrected, thanks

amaineman57 says: Sep 27, 2009. 3:47 PM REPSuper Ible! The only comment I would make after viewing the video is the need of prop guards to keep the umbilical from fouling the props. Other than thatGood show!

awang8 says: Nov 16, 2008. 7:26 PM REPwhere can you buy a cheap 12v camera?

Spark fun costs AUD50 which is way too much.

Pyrotechnic-Robot says: Dec 30, 2008. 8:42 AM REPEbay! I got my first few cameras from ebay I know you dislike ebay but I found for a mini camera for about 30$ My first was 12$ but the prices reallypopped up The sub that I am making will have one of my old wireless camera

awang8 says: Dec 30, 2008. 2:26 PM REPEBay eh? Sometimes they're fake cameras and I hate them. Like, they claim to be real cameras and you end up with a el cheapo dummy camera.??q? uo p??oq??? ? ?nq o? ?u?o? ?? ? ???? ?s?? ??? s? s???

Pyrotechnic-Robot says: Dec 30, 2008. 4:21 PM REPif you look for a mini spy camera you might find another camera. How did you type upside down? sweet.

awang8 says: Dec 31, 2008. 3:19 PM REPHow to type upside down.

1. Log on to www.ebay.com2. Search "Keyboard" with the 2nd hand option.3. Buy the cheapest one you can find.4. There you go! You got successfully scammed and you should now be able to type upside down!

Just kidding

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clayball97 says: Aug 19, 2009. 8:35 AM REPserously though how do you type upside down

Pyrotechnic-Robot says: Aug 19, 2009. 10:39 AM REP?? ???oo?

daniel2008 says: Dec 24, 2008. 1:04 AM REPwell you cna get cheap 'spy' cams on ebay which run on anything round 9 V, you could have a 9V battery inside the housing connected to your cameraand then run the video cables up to the surface

awang8 says: Dec 25, 2008. 8:55 PM REPI'm not fond of ebay... I t looks like i'm going for the Spark Fun. The webcam quality in my country is absolutely garbage.

awang8 says: Dec 30, 2008. 4:26 AM REPAlright, I bought a $50 security camera with RCA output from DIck Smith Electronics. The downside is that I have to use an adapter. Stay tunedmy Intructable is coming!

SpaceShipOne says: Dec 31, 2008. 4:53 PM REPSounds like you're off to a good start. I can't wait to see how it turns out!

awang8 says: Dec 31, 2008. 8:20 PM REPIt's based on the SeaFox so really it isn't that good. The most expensive parts were the pumps and the camera.

DELETED_craz meanman says: Jan 4, 2009. 10:54 A(removed by author or community request)

DELETED_craz meanman says: Jan 4, 2009. 10:56 A(removed by author or community request)

awang8 says: Jan 4, 2009. 3:02 PM REP1. I've heard that webcam's frame rates are very low. Expect laggy video. 2. No, they're probably just right with propellers.

DELETED_craz meanman says: Jan 8, 2009. 2:02 P(removed by author or community request)

daniel2008 says: Jan 9, 2009. 6:03 AM REPyeah, bilge pumps are pretty expensive, but you can use 3, so expect 40-60$ on that. But are you going to run 12Vdirectly to the motors?...in which case you have to use wire that is thick enough to conduct over long distances but thenough to be flexible.

awang8 says: Jan 14, 2009. 8:47 PM REPActually, 3 1100GPH bilge pumps cost about $210, add $30 for the prop and adapter and there you go. 5/6 of yobudget gone.

awang8 says: Jan 12, 2009. 4:30 PM REPAKA lots and lots oh 24 gauge wires twisted together.

daniel2008 says: Jan 13, 2009. 4:25 AM REPyeah...

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bananafred says:Or a piece of 14 gauge speaker wire.. . http://cgi.ebay.com/Pro-Audio-Premium-14-Gauge-Speaker-Wire-100-SW14_W0QQitemZ380091593512QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item380091593512

awang8 says: Jan 14, 2009. 8:48 PM REPThats expensive and not really flexible enough. Plus, speaker wire is solid core so it snaps easily.

SpaceShipOne says: Jan 14, 2009. 11:08 PM REPI was able to get 1100 GPH bilge pumps for about $30. Props were about $6 and adapters $3-4.

However, if you are using props, the 500s will work fine. I have limited the full power of the 1100s dueamp draw and the fact that I don't need to go fast.

pic16f630 says: May 21, 2009. 7:22 AM REPVery interesting. I wonder where did you get that electronic compass....

Pyrotechnic-Robot says: Aug 19, 2009. 10:36 AM REPalright so it is quite easy to make this compass.FIrst you have to go to Zargos Robotics and get the compass sensor. it is located at their very bottom of the pagehttps://www.zagrosrobotics.com/Index.aspthen what I did is I made a little pcb board to fit the sensor and the lights and the output. I can give you the layout that I made if you would like it.???Just to tell you this compass is very finicky.

SpaceShipOne says: May 21, 2009. 12:38 PM REPI got it f rom a robotics website. It is a fairly standard compass used for navigation on robots. Its a Dinsmore 1490. A search online should yield severaldifferent stores that stock it

Q branch says: Jul 21, 2009. 1:29 PM REPreally cool! i'll have to do this one sometime... what water current speeds can it handle?

cdvideo says: Jun 28, 2009. 5:01 PM REPHow deep have you gone with this ROV and how well is the RC control I have 3 30amp ESC and was going to use servo controllers from the surface 3wires that is why I am asking If the RC transmitter transmitting to your teather works at 150 feet I can save 2 wires for a fish finder to show me the bottomcontour.

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