So I want to try to build a more affordable ROV which is a littlebit smaller and limited to max 100m depth.
So maybe someone will know if this is a bad idea or not.
Here is the plan to reduce cost.
-3d printable frame, but probably still use proper blue robotics enclosure housing/dome and pentrators, not sure how to do this cheaper without Compremising waterproofing and reliability.
-8x M060 thruster, (about 30$ a pieces.)
-No Fathom-X Tether, instead use ethernet tether directly from computer to raspberry pi (100m limit), but possibly 1 Gbit connection!
-use 2x 4in1 drone ESC, Model Sequre Blueson ESC 4in1 A2 2-6S 65A AM32 (50$ a piece in my country).
-Flight controller model, Sequre H743 4-8S Dual BEC FC, (80$ a piece in my country).
-Raspberry pi 4 or 5 (I currently have Pi 5 4gb).
A little diagram made with chat gpt, not 100% correctly wired but you get the idea.
Is there a particular reason to prioritise 6DoF control? I feel like reducing the controlled motion axes is a common cost-cutting measure (even a standard BlueROV2 has no pitch control), and more generally it’s interesting you’ve opted for 8 thrusters rather than a more limited set. 6DoF is technically possible with only 6 thrusters, though there are some inefficiencies with doing so.
If you manage to source an affordable 100m tether that can reliably achieve 1Gbps (or even >50Mbps) data rates over just ethernet, please let us know - there are likely several users who’d be interested. Bonus points if it’s neutrally buoyant, strong enough not to break when pulled on, cut+abrasion resistant, and ideally water-blocked
This is included in ArduPilot’s automatic firmware builds, so should hopefully work. Just be aware that boards not included in commercial vehicles will have had substantially less testing with ArduSub (if any at all), so it’s possible there’ll be some extra configuration required, and/or some debugging to make sure standard functionalities work as expected.
We’re happy to help to the extent we can, but without access to the hardware there are likely more limitations to the support we can provide.
You haven’t mentioned any details around (and hence may want to put some extra thought into):
It can absolutly have 6 motors, I was just thinking since i need 2x 4in esc boards I have 8 esc´s which is still WAY cheaper than buying 6 single ones.
I have never used a ROV before only built and used FPV drones so I dont know how good of control you get with 6 motors but seems fine too.
Having 6 DOF with 6 thrusters is that supported in ardusub? If thrusters is angled like the
FIFISH V-EVO rov? Could be cool!
As long as its a cat5 or better cable which has som sort of rope/ kevelar and a protective outer shell, I think it should work, Ive read the network cable was rated upto 100m with full speed, and I would then also think it is reliable as long as the cable dont get bend or kinked to extreme but I might be totally wrong on this.
But I might have to test it to be sure, I have some ideas allready.
Camera: Im still trying to find a very good clear camera, I have allready a Logitech C920 H264, but for some strange reason I only get it to work in 1080p 8fps h264, any other res or fps the stream just gets lost. I also have raspberry pi hq with 2 different lenses but since its not h264 i think it will cost to much prosessing, I havnt tested yet.
Depth sensor: thinking about a blue robotics I2C
Battery: I have some different LiPO and Li-ion drone batteries, I also have 18650 cells and tools to make my own packs if I need to utilize a limited volume for battery storage.
Powermonitor: the esc´s have current sensors and the fc has voltage monitor, not sure how they will work with blueOS or ardusub but as long as Im able to read the voltage Im happy.
Leak sensor: if there is some kind of i2c compatible deviec it could work or I might just do it the “easy way” use a arduino with a sensor to detect leak and just blink a red LED near the camera lens so it gets picked up if there is no I/O the FC board that can detect it.
Updated with CAD renders playing with the idea of a mini frame made to fit M060 thrusters but still using full size enclosure 4" x 300mm
-Also added scale comparison between Bluerov2
Depending on the board and what else you want to run on it, that might be ok. On the Pi4 there’s a dedicated video encoder chip, so the rest of the processor is largely unaffected (as I understand it).
BR leak detector functionality is just reliant on a digital input pin. Should be pretty straightforward to set up something equivalent if your flight controller board has such a pin available, but you’d need to check
I have built a very small ROV with only 4 thrusters, using a mixture of BR and other components:
single BR enclosure (D=50mm L=300mm)
4 x APISQUEEN X1 thrusters with 45A bi-directional ESCs
BR Navigator / RPi 4
Fathom X tether and interface boards
BR Low-Light HD USB Camera
Bar30 depth sensor
gimble servo with custom mount
custom built 8x18650 battery back (4S2P)
alum. and PLA 3D printed frame
The challenge was fitting all the components into the small enclosure, but the system works well based on initial pool testing (yet to be ocean tested). I am using Cockpit and a game controller on the topside laptop. I designed the alum. frame and thrusters to detach easily when the enclosure needs to be opened (for battery change etc.) Only weights a couple of kg.
Yes, I am happy to publish the stl files. I will create a new post in the Build category to introduce the project and make the stl files available. It might take me a day ot two to organise.
