Homebuilt ROVs Forum

I have been wanting to work on ROV for a while, but have been very busy with work, now finally got some spare time to work on some ideas.

I design camera mounts, pods for FPV planes, custom ground stations and I also fly multi rotors so I wanted to have the steady multi rotor control on my ROV too. From all the designs I have seen (3,4,5,6 thrusters) I went with what the expensive commercial ROV's are using for my first project..... 6 Thrusters design

Thrusters = I decided to go with (6) Turingy 28mm 750kv brushless motors with some Traxxas Villain 44mm propellers (right and left rotation props), I plan to switch the metal bearings to custom teflon or delrin bushings, change screws to stainless steel and so on, some epoxy waterproofing to some internals will be made too. (motors will be easy to replace if they get damaged)....this is until I find better motors.

ROV Battery = (2-3) 3S 5200mAh Lipo batteries

ESC's = I will be using some hobby king boat 30amp (forward/reverse) brushless ESC's.

ROV Control= I might go with a PPM signal from my RC radio to the ROV, to control all the ESC's and RC switches etc. less wires.

Video = will consist on 4 Cameras, (1) GoPro Hero 4 and (3) Sony 700TVL Cameras (with the option of mechanically removing the IR filters for better low light) always providing live video feed to the surface DVR. (Front, Bottom, Back)......The GoPro and Front 700TVL camera will be mounted on a 2-Axis Brushless Gimbal, with Tilt control.....A Remzibi OSD will be added on the front camera to show direction, depth, battery power, temp, and any other sensor I can add to it.

Ground Station = Pelican style case, 19" Widescreen LCD or 12" Sun-readable monitor, 4ch SSD DVR, custom 9ch radio controller, 19Ah SLA battery.

I have many other parts to add as I go, I'm still deciding what dome/tube combo to buy or built, what tether cable I should use, but I will put my progress as I go.

So far here are some pictures of the frame I'm making (Laser cut high impact ABS) motors and propellers are not the ones I will be using, but you get the idea on how it would look like. The ground station monitor and case is the one I will be using but with a different bottom plate.

I will post more pictures as I go, any input will be appreciated too.

Very nice project, thank you for sharing. Two questions: which Sony camera did you decide to use? and won't the 19" widescreen stretch the NTSC signal from the camera to fit the screen? I was considering getting a bigger screen but didn't want to stretch the image to fit a HD widescreen.

The cameras that I plan to use are from swann security, they use the Sony Effio chip and at night the mechanically remove the IR filter for better low light, I will have that feature wired to an RC switch. They come in their own waterproof case, and instead of the IR Leds I will add white LEDs around the lens. I also have other small board 700tvl cameras from my FPV planes that I can test.

The camera is 4:3 fotmat but it doesn't look that bad stretched to 16:9 widescreen format, I have a 4:3 12" inch 1500nits military grade LCD monitor that I might use, that its sun readable, the 19" its only 400nits brightness and it will require a hood under the sun wich I dont like that much. The 19" is better for roofed boats, my boat is a Seadoo Jet Boat 15' with a soft canopy. Not to much room to work on it, and the 12" LCD works great under direct sunlight.

Hi CRD....

Regarding the PPM signal, do you intend to have a topside RX, then output PPM through the tether? what would be your subside controls? PPM to PWM converter? or something else?

I'm toying with this idea for another project i've considered once my baby ROV is complete.

Bindo wrote:Hi CRD....

Regarding the PPM signal, do you intend to have a topside RX, then output PPM through the tether? what would be your subside controls? PPM to PWM converter? or something else?

I'm toying with this idea for another project i've considered once my baby ROV is complete.

I'm still deciding and researching my options about the PPM PWM signal, I don't want to use any arduino or similar controller, I like the simplicity of the RC control and RC controlled OSD, plus RC on/off switches are small easy to connect/replace etc. Programing and mixing the motor movement in the radio is very easy too.

I'm also considering a wireless connection (control and video) via a RX Buoy. I have a some powerful Control and Video Transmitters to play with too. With the proper antenna I could take my ROV miles out to sea and control it wirelessly from shore. I can add a lightweight solar panel to the Buoy and supply power to the ROV for longer trips

I plan to use this ROV on the coasts of Puerto Rico, most of the fund stuff is in the 50 feet or less.

I am curious to see how long the tether can be wen sending PPM over it. Do you have any idea about this yet?

olegodo wrote:I am curious to see how long the tether can be wen sending PPM over it. Do you have any idea about this yet?

I'm waiting for some electronics to test this too.

But another option will be using a normal 2.4ghz radio control TX/RX.
RX will be inside the ROV with a very long 1.13mm flex coax cable and then the antenna portion will be by the ground station. I will make a diagram and post it soon.

Here are to option that might work, assuming the coax antenna cable doesn't break.

Welcome crd, and nice design with the laser cutting etc. I can appreciate why you are wanting to use coax, but be aware that thin coax is very "lossy" ie, has high attenuation at the frequencies you are using. Looking at a data sheet, at 1GHz it is about 1.5dB per metre, meaning that for every two metres of cable the signal is halved in strength. I don't know what this translates to in usable length, but it won't be much, even if you plugged directly from transmitter to receiver, which could do damage to receiver anyway.
Dropping the frequency would allow greater tether length, but you will have trouble sourcing RC and video transmitters and receivers for lower frequencies.
Option 1 in your sketch would be good if you put the radio gear in the buoy and ran the camera and ppm signals through the coaxial cables.

Hope that helps rather than hinders

rossrov wrote:Welcome crd, and nice design with the laser cutting etc. I can appreciate why you are wanting to use coax, but be aware that thin coax is very "lossy" ie, has high attenuation at the frequencies you are using. Looking at a data sheet, at 1GHz it is about 1.5dB per metre, meaning that for every two metres of cable the signal is halved in strength. I don't know what this translates to in usable length, but it won't be much, even if you plugged directly from transmitter to receiver, which could do damage to receiver anyway.
Dropping the frequency would allow greater tether length, but you will have trouble sourcing RC and video transmitters and receivers for lower frequencies.
Option 1 in your sketch would be good if you put the radio gear in the buoy and ran the camera and ppm signals through the coaxial cables.

Hope that helps rather than hinders

Any input is appreciated, I might be able to find some 27mhz and 40mhz R/C TX and RX's but they are limited. I would like to try the PPM signal without any control TX or RX via cable first. Can't wait to start building it, I'm just waiting on some electronics and the propellers.

A little update, I was planning on making a custom hull, but I found a nice waterproof camera housing on eBay that might fit my bill for now.

for $75 shipped is worth a try.