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Ethernet (Fathom-X) interface question

What is needed, software and hardware wise, to interface via Fathom-X boards with a Windows computer on one end and ESC’s and video camera on the other? I want to stay as basic as possible.

Bare minimum on the topside would just be the fathom-x board and an ethernet cable and a usb to usb mini cable, also install QGroundControl on the laptop with a game controller.

Subsea is a little more complex. I think the bare minimum, hardware-wise, would be the other fathom-x and an arduino, but I’m not sure if the programming is such that it’s just a matter of loading a file. I see bits and pieces and sample code, but I don’t think there’s anything complete for a 6/8 thruster rov with x camera and x depth sensor, etc. But, if you can program, this would be the most basic route.

You can remove the Raspberry Pi if you use the fathom-s boards, but if you want to use the fathom-x boards, you pretty much need the entire advanced electronics package. You can save ten bucks buying the Pi on eBay, or maybe $40 on the Pixhawk, but it’s a gamble whether or not it will work. In the end it’s not worth piecing a cheaper kit together, imo, because invariably it won’t be plug and play.

Since I am looking only to control two ESC’s (driving two thrusters) and video capability, it appears the “advanced electronic package for the Blue ROV” , minus the autopilot, would meet my requirements. Do you agree?

The Pixhawk is where you plug in the ESC’s, so you’d need it for control. If it’s just two thrusters and you were going for bare minimum, I think all you really need to do is get potentiometer signal across a couple arduino’s and then use the Thruster Commander. You should be able to find code for that.

I built multiple ROV’s using the Arduino with top side resistor control route three years ago. I posted on this site a lot, showing my work. Here is a video of the last and most complex project: https://www.youtube.com/watch?v=89MDyKCcxdE. My underwater videos are posted on this channel site, also.
I want to build a project using two-wire control so that I may use the thin tether and a 3" enclosure. The Blue ROV is much too large and cumbersome to use in the deep, high current, and rough water environment where I need my ROV to operate. Our fishing boats are small and pitching all over the place. All I want is right -left control of a drop-down, heavy weighted enclosure, and perhaps camera movement control. Measurement of depth and temperature sent topside would be a plus.

I believe you can fit the advanced electronics package into a 3" bottle. Might not be fun, but you can do it and hopefully only do it once.

I think the problem isn’t so much the size as much as that it’s not a “free air” design like yours shown in that youtube link, so I don’t think the 3" vs 4" bottle will do nearly as much as using the bottle like a frame and getting the thrusters out on posts like you’ve done.

Are all functions of the Blue ROV2 able to be carried out via a 2-wire tether. If so, why would one use the fatter and twice as expensive 4 twisted pairs tether?

I believe my new project goals will be best achieved sticking with Arduino and an ethernet shield. I can have my desired thinner tether and I am familiar with Arduino code.

The larger tether will communicate up to 300m and the smaller tether is only 200m, plus the larger tether has more passes for other electrical things, but yes all the standard functions of the Pixhawk and gripper/lights/ping/depth sensor etc can be used with the small tether.

Thanks for answering my questions.

Back to square one! Arduino does not have video capability.

I guess it will have to be the Pi 4, a whole new learning experience for me. At least I will be able to get help on this forum.

I’m not sure?, but i think Ardusub only runs on the Pi3, not the B+ or the new Pi 4…

I use the Pi3 to control an SSC32 servo-controller via I2C, which controls all my servos, lights, manipulators, ballast drop, bouyancy air valve, etc. The only thing i use the Pixhawk for is the autopilot thruster control. Using the Fathom-X boards i can control the ROV + send video from 8 cameras via my onboard DVR board, connected to a 4-port ethernet switch. Both the Pi and the DVR are plugged into the 4-port switch in the ROV.

I don’t intend to use Ardusub. This is just for a drop down camera with two thrusters to provide rotation and a small amount of forward and back movement.

I agree the Pi 3 is proper for my project due to the I/O pins.