A couple people and myself are looking into building a deeper water ROV. Our biggest obstacle is the Tether. Has anyone here built an ROV that can pointbusnint the right direction?
Rov
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Darkforeboding
Contributor
The Forum that I like is this one:
Homebuilt Rovs
You've hit on the biggest engineering problem. If you power the ROV from the surface you wind up using large guage conductors or there is a lot of voltage drop between the power supply and the ROV. Large conductors mean a less flexible, heavier umbilical and problems. The other option is using a control cable from the surface and batteries in the ROV and you have a heavier ROV and larger pressure vessel to store them. Some of the hobbyists use programmable controllers such as an arduino and 8 conductor cheap network cabling for control cable. Both ideas have plusses and minuses.
DFB
Homebuilt Rovs
You've hit on the biggest engineering problem. If you power the ROV from the surface you wind up using large guage conductors or there is a lot of voltage drop between the power supply and the ROV. Large conductors mean a less flexible, heavier umbilical and problems. The other option is using a control cable from the surface and batteries in the ROV and you have a heavier ROV and larger pressure vessel to store them. Some of the hobbyists use programmable controllers such as an arduino and 8 conductor cheap network cabling for control cable. Both ideas have plusses and minuses.
DFB
OP
Yes, I seem to be the only one building a deep water ROV that I want the ability to go down 300ft. That means I that I need either 500 or 550ft of tether, which means a large power supply, also in the tether needs to be the video feed. I am leaning towards a design similar to JW Fisheries Sea Otter.
Some mates and I look at this a while back but never made one, the cost was going to be too much for us. This was what we worked out. The biggest problem is not power but communications the best solution we came up with was use internal batteries and then run an optic fibre cable as length is not an issue and is more reliable. For controlling the unit I would suggest a raspberry pi and Arduino combo. Software is open source.
PM me if you need any help, I think we found solutions for most of the major design problems
Sent from my iPhone using Tapatalk
PM me if you need any help, I think we found solutions for most of the major design problems
Sent from my iPhone using Tapatalk
Do you mean running the ROV from surface power? Why not just use rechargeable on-board batteries and then you just have to tether the data/video and provide an actual safety tether (to prevent loss in the event of comms outage or power failure). Heavier unit but much simpler task, in my opinion and it will also allow for no/less ballast requirement to get to depth.
OP
How am I to control it if it has battery powered thrusters? It's going to be used on deep shipwrecks and powerful enough to do seawall inspections on the river. For the shipwrecks, I want to use it to penetrate some areas that are non accessible to us with doubles and slings. And remember that I dive the Great Lakes and in autumn it gets dark and gloomy past 90ft and almost black at 200.
This is what I would recommend with a max cable length of 100m after that you will need to go to optic fiber due to signal lengths and install an optic fiber capable router then interface that with a computer on the surface
Batteries on the Rov as a control cable failure will leave it dead in the water
Install an Arduino mega as the micro controller, a small router and an IP web cam in the ROV, this will create a small network that can be linked back to a computer ie Raspberry Pi.
Making sure the cable you use is water proof most are not.
The Arduino is capable of acting as a web server/client and can be accesed via a web page giving you total control.
The motor controllers, servos depth sensors light controllers and alike all get passed through the Arduino via software to the browser.
The video is sent back directly from the camera to the browser and can be recorded on the computer.
The Arduino can be programmed to respond to loss of coms, water ingress automatically and return to the surface, scuttle or anything you want it to do.
If you want to get very creative with the software you could have it dive a pre determined pattern of have it track a image from the camera.
Batteries on the Rov as a control cable failure will leave it dead in the water
Install an Arduino mega as the micro controller, a small router and an IP web cam in the ROV, this will create a small network that can be linked back to a computer ie Raspberry Pi.
Making sure the cable you use is water proof most are not.
The Arduino is capable of acting as a web server/client and can be accesed via a web page giving you total control.
The motor controllers, servos depth sensors light controllers and alike all get passed through the Arduino via software to the browser.
The video is sent back directly from the camera to the browser and can be recorded on the computer.
The Arduino can be programmed to respond to loss of coms, water ingress automatically and return to the surface, scuttle or anything you want it to do.
If you want to get very creative with the software you could have it dive a pre determined pattern of have it track a image from the camera.
How you control it has absolutely nothing to do with where the power comes from for the thrusters. They are completely different signals with a whole host of different options. If you have a tether that provides your command and control data path, it is (typically) a better design option to provide on-board power than to try and run power (inefficiently) from the surface. DC power doesn't travel long distances well and the cable you'd need to run it would be a low gauge and very heavy. AC power requires completely different thrusters that are generally significantly higher cost (especially for submersible ones) and also heavier/larger, typically.
As others have indicated, a fiber optic cable for C2 data will give you the most flexibility and best performance. On-board battery power that feeds the controller and the thrusters. As simple or complex as you want it to be as far as capability.
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