NEW PRODUCT- External Light Cube


We are extremely happy to announce a new product just in time for the holiday season!

We have been hard at work over the past year designing a versatile and powerful external light cube for underwater vehicles. After many iterations we have a product we are extremely happy to announce and we hope you enjoy it.

Get yours today!

These pre-built 17mm cubes produce 700 lumens (each) of continuous light over a wide input voltage range. They easily integrate into your current OpenROV or any other underwater project. They are fully dimmable and are supported in the latest software release (30.0.3).

They have been tested to a depth of 200m, but since there are no air cavities, they can go much deeper.

We would love to hear your feedback on these lights and please let us know if you have any questions.

Modification Shell

YES!!! They look great!

Question: How many can I string together either in series or parallel? I have 4 battery tubes, so I’m good for power I was just wondering how much draw the controller board can take. I was planning on installing 4, two on each side of my “Beast”.


On the 2.8 Controller Board each PWM channel can handle 2A. PWM3 is already wired for external lights. PWM4 can be wired to control external lights as well (jumper on R35) and then add in the control on this channel in software. This amount of power through the current monitor will saturate the measurement so you will not get an accurate board current number (but will not hurt anything).

At battery voltage (9.6V) each light is drawing about 0.7A at full power. This would put the limit at 2 external lights in parallel (which is what we have on the store). You can probably add three in parallel on each PWM channel (and be just over the 2A max) and be ok, but I will let @Walt_Holm comment on that. This would bring the total to 6 external lights.

If you use both PWM3 and PWM4 you can control 4 lights with a small jumper on the board and a software change without any issues.

My ROV for college project

Thanks @Brian_Grau. I already stripped out my 2.7 Light Board from my E-Chassis so I was going to use one set from that (PWM1) and plug the second set into PWM3. This will work out perfectly, I’m glad I potted all those extra wires :smile:


I am glad you potted all the extra wires as well. With this setup there are no software changes that need to be made :slight_smile: I can’t wait to see the light cubes on your ROV!


Hi Kevin and Brian:

I would be cautious about adding any more than 2 Light cubes to the overall power system of the ROV, at least until you make some modifications to the controller board.

The non-esc battery bus was designed conservatively around a 2A maximum current draw, which is about where it’s at when you have a pair of Light Cubes attached to the ROV and everything else running. As Brian noted, the current monitor will saturate at 2A, which is not in itself a problem, but the sense resistor R12 (see the controller board schematic sheet #3) will start to overheat at about 3A. The way I look at it you have three options:

1.) Stick with one pair of light cubes and everything will work fine.

2.) Use three light cubes, two on one PWM channel and one on a second channel. Stresses out the power system a bit, but will probably be OK. I’ve never actually tested this.

3.) Use four light cubes, two on one PWM channel and two on another. Replace R12 with a smaller resistor (say, 0.010 ohms) to reset the range of the A/D converter. If you like, patch the Arduino software to provide accurate current monitoring on that channel.

On the “feature list” for the next generation of controller board is to break out the existing non-ESC current monitoring into two separate channels, one for internal loads and one for external loads. That would give me an opportunity to resize everything to allow bigger external LEDs. I should also do this on my experimental 6-ESC board.



Thanks for the technical on the controller board @Walt_Holm , I thought that might have been an issue from our discussions, but wanted to make sure.

Looks like I’ll end up mounting 4 anyway and just not wiring up the 2 extra until a future controller board can support it.


Hey Brian.
We have some Cree LEDs here from another project and I was going to try a couple, (I love the light cubes, but really can’t afford to get them at the moment). They won’t be as bright as yours but might improve things a bit.

Can I just hang them straight onto a PWM channel? I’m running 30.0.3 on my 2.8 ROV. Do I need any software changes? What controls the brightness and limits the current to under 2A? Do the keyboard keys IO&P do all the lights, inc the PWM channels or would I need to change the key assignments? Sorry, so many questions.


Can’t wait to see your lights!

You can look through the full schematics on the GitHub site for the controller board.

Specifically sheet 6 and PWM3.

For the 30.0.3 software the controls for the PWM3 channel is alt+the light control (I,O,P).
e.g. full on alt+I

The brightness is PWM controlled. You will need to design your circuitry to not go above 2A. If you go above 2A total on the PWM bus you can damage the controller board.

I hope this answers the questions that you have. Please feel free to post additional ones if you have them.


Got my lights today :slight_smile: Good timing too as I finish up the rest of the wiring for the thrusters.


We have published the instructions on how to connect the external lights to your OpenROV. If you have a 2.5, 2.6, or 2.7 you will need to do a small modification to your controller board.



I just finished my Openrov, and want to install 2 Light cubes before my first dive…

the lights are soldered parallel to both purple wires…( 2 red on 1 Purple/red, 2 black on Purple/black)

  • the shrink Tube is not closing the end with both wires perfectly……
    I think of potting them in small tubes with 2K Expoxy…
    …or do you have any other solution…?




If you use a long piece (there should be plenty that came with the lights) you should be able to get the inside to ooze out both ends and seal the connection.

If this is not working you can seal the joint with epoxy like you mentioned. I can’t think of anything easier at the moment.

Good luck and I would love to see pictures about how you mounted your light cubes.


Hi Brian,

yes, sorry for asking :wink: … but as a novice I thought better ask before ruining anything…

And yes it is very easy…

I am looking for some adjustable fixings so I can experiment with the right angle and adjust them when using a go pro…a kind of ball joint.
I will first install go pro and light on top of the ROV, so no damage occurs when hitting the bottom…or any bad sight when bottom particles will form clouds of dust…

No more questions for the moment! and this for answering so quickly…also within the instructions pages.



@Roel_Haagmans no problem. Please post pictures of the mounted solution when it is done :slight_smile:


Hi everybody i make a adjustable fix and bump protection,for external lights cube, hope work fine in my first dive. thanks Brian_Grau,




Here’s another example, that isn’t as innovative and robust as @jimmy’s:

I used hot glue and zipties on maker beam brackets. If you cinch the ties down fairly hard, the lights are pretty secure, as in I haven’t knocked one loose yet. This is just temporary until I man up and epoxy them on the brackets, but right now they can be easily removed.



I have my external light cubes mounted in such a way that they are fully adjustable.

I have used parts of the legs of a small “octopus” tripod.
These are easily pulled apart , so you can make the arms as long as you want.
Just using 2 segments makes a small joint, I used 5 to have as much freedom as possible.

Due to the flexibility the arm takes no damage if bumped into something, or during transport.

I have glued a M4 Stainless Steel bolt into one endcap and glued the other end to the light cube.
Please use enough 2K Glue and heat it , so there are no air bubbles trapped, and the glue covers the complete area.

Drill a 4 mm Hole, and mount them wherever you want.
I´ve chooses the front , so they have a clear field of operation, nothing in-between.

A small tripod costs 12 €, with enough elements to mount anything else additionally.

Have fun!



Fantastic post @Roel_Haagmans. These look great and I can’t wait to see video and pictures of them working underwater!


The External Light Cubes appear to have not been in stock for a while now since the last batch sold out.
Is there an ETA now for the next batch of Cubes?