The BorgCube ROV build


Okay folk, I’ve been encourage to post my build progress, such as it is, so people can take a look, follow along, comment, and be generally helpful and point out my foolishness. So here we go …

I became interested in ROVs last year and decided I should build my own. By profession I’m a software/hardware engineer, so rather than doing the sensible thing and buying an OpenROV kit as my first project, I decided to build everything - the robot frame, its electronics, and its software - from scratch. To make my life every harder, I have given this thing stereo vision (two movable cameras), an underwater manipulator arm, and 12 (yes I know) thrusters to give the ROV complete freedom of movement in the water. And because software for such a bot doesn’t exists, I’m writing that too. One could charitably call this “experimental”.

The above photo is a snapshot as the BorgCube sits on my floor this evening. No thrusters attached yet, and the electronics are currently on my desk. I will try to update as assembly continues.

Much more information on this build can be found on Hackaday ( and the software (very much a work in progress) is on GitHub (

I have lots of work to do yet, but feedback/encouragement/constructive criticism is appreciated.

Will it work in a big river?

Hi Tim,
I’ve been following your posts over on Hackaday for a few weeks now and I am most intrigued. Nice to see I’m not the only one building big :slightly_smiling:

A manipulator arm is definitely on my to-do list, however the current crop of waterproof servos aren’t depth rated for anything meaningful. Here is a bit of a review on the Traxxas ones. I imagine the Hi-tec ones would be the same. ( anyway I’m interested to see how it turns out.


I fully expect the manipulator servos to fail - but I’m interested in how they fail and how deep (or not) they get before it happens. Then I’ll probably look at rebuilding them and seeing what’s possible. I did consider opening them up now … but I’m trying to resist finding too many ways to not actually finish building this thing.


Well I tell you what, even if you get the controls to work, that would be a victory. You are right, we can work out the hardware details later and using something cheap and off the shelf is really good to get you started.

I still have about 1lb left of buoyancy to work with in the bow of mine, so I’ll go about making one up too and working on some sort of control over Ethernet for it.


Time for an update … and I can put it off no longer … the 'Cube is assembled and I have to put it in the water. Eek! Tomorrow I’ll be dropping it in the hot tub in the yard and seeing how it goes. I’m expecting it to float still (it weights about 20lbs but there’s quite a bit of buoyancy due to the three airtight tubes) so will have to look at fixing that. Mostly I just want to run a few simple tests and make sure it works. Nothing fancy yet. If it does sink I will probably start working on the PID controllers for balance.

In the meantime, here’s the fully assembled thing:


Also - here’s the current cockpit view (looking out at the mysterious underwater world which is my office) - much to do here yet. The UI is written using three.js, a rather good WebGL library. I chose it because it let’s me easy switch the UI to VR mode.


Looks good Tim, good luck with the trials tomorrow. 20lbs is pretty reasonable and many of the larger homebuilt ones are coming in around this size and weight. mine was 21.5lbs when I was done with it.


Did the water test this morning (before it started raining) and nothing leaks and all the electrics work! As you can see in the photo, it floats so I need to fix that. Lead weights?


I am deeply impressed ! Congratulations from Luxembourg.


Amazing work! Very impressive!


Tim, looks great! Always a plus when you don’t have to add more bouyancy.

For the weights I use a combination of solid dive belt weights and disk fishing weights. Both are easy to ziptie on the frame. You will want a few different bags of the fishing weights (1oz, 2oz, 3oz, etc) so you can really dial in the balance.

Solid Dive Weights
Disk Fishing Weights


Outstanding Tim. Good luck.


Looks fantastic, very impressive Tim!


Thanks for these recommendations, much appreciated - I’ll check them out.