New here, and I have a few questions about BlueROV2

Moderators: If this is in an inappropriate location, please move it to where ever it belongs. Thanks.

Hi All,

I’ve built two OpenROV 2.8s in the past, and now I’m considering a BlueROVs. My goal is build something reliable enough to take into the field with students to collect water samples at specified depths. Ultimately, I’d like to use a large Niskin bottle to collect samples as big as four liters so we can check it for coliforms, microplastics or eDNA.

I’ve been reading some of the guides, trying to figure out what I’d need to start out. So far I think I’d need the following:

What else would you recommend getting? I’ve seen this thread about laptops where it mentions the Surface Pro, Samsung Notebook 9 Pro, Lenovo Miix 700, Which of those is the most popular for the BlueROV2 with Fathom X-tether?

1 Like

Welcome

Just curious, why would you use an ROV for water sampling?

If you start the dive with an empty bottle and open it at depth, you will loose app 4 kg of bouyancy.

For top side, choose a platform with a large HD and good graffic performance.

1 Like

A Niskin bottle is open at both ends until it closes; think of a tube with end caps that snap in place. (Everything that we’re doing is based on the Niskin design from Andrew Thaler.) That won’t affect buoyancy quite as much as you are thinking, but we are trying to scale up to much larger sizes that do have a lot of mass. That’s why I’m interested in a bigger ROV with large payloads and strong thrusters.

Still, those are good question. There are several reasons.

  • Not all of my biology students are SCUBA certified. I’m trying to get ALL the students involved.
  • We should be able to send an ROV to take samples in places we can’t send a diver. The recreational SCUBA limit is 120 feet. Exceeding it takes additional training and money. Going to 300 feet takes a LOT of training, money and danger.
  • We should be able to send ROVs to places we would not want to go. (Example: Blue heron bridge after Hurricane Irma, when the water was closed due to bacterial contamination from sewage runoff.)
  • Little samples are good for things like looking at bacterial contamination, but you need bigger samples if you want to look at eDNA or microplastics

Everything that we’re doing right now is small scale, but we’d like to take much larger samples at deeper depths than we can go.

Hi @JoeyM, that’s an awesome application, and we’re glad you are interested in the BlueROV2 to carry your sampling devices (love the diy design of the big one!).

I think the list you put down is fine. As far as computers goes, QGroundControl should work with any modern computer. Somthing to look out for is a nice bright screen. We use the Samsung 9 Pro.

-Jacob

1 Like

Thanks. I’m still working on the buoyancy of the big bottle, hence the bench test instead of a tank test. It can grab four liters, though, and that’s enough for eDNA. I know some folks who would LOVE to test for eDNA at 300’ without having to send divers down that far.

We’re currently using chromebooks to run the OpenROVs since it is better to keep inexpensive laptops near the water. Unfortunately, I don’t think QGroundControl can run on a chromebook. I appreciate your recommendation of the Samsung 9 Pro. Does that have the ability to run FPV goggles? I’ve been dabbling with that on the OpenROV…

Hi @JoeyM,

Very cool. I would love to see this work out for you.

The Advanced Electronics Package is already included (and pre-installed) in the BlueROV2 kit, so there’s no need to purchase that separately. The Spares Kit and the Payload Skid are a good idea.

We’ve had one report of someone getting QGroundControl to run on a Chromebook, but I’m not sure how much effort that took. You’d probably have to compile it on the Chromebook.

-Rusty

1 Like

Thanks for the heads up. It saves money to not buy the electronics twice. :sunglasses:

I’ll just plan on using that money towards getting a different laptop

Do you have suggestions for making payload skid clamps? Yours - according to video - are 4", and the PVC main tube of our large Niskin is 4" INNER diameter, so we’d need to make some clamps.

Hi Joey,

Sounds good :slight_smile:

We made the prototypes of our aluminum clamps with 3d printing and they worked just as well as the aluminum ones. We couldn’t have tapped holes so we needed to use nuts with the screws. I’d recommend giving that a shot.

-Rusty

Thanks for clarifying the bouyancy aspect :wink:

What is the reason for not using the Niskin with a drop Messenger from surface on the decired depth?

1 Like

@JoeyM QGC will not run on ChromeOS. If you put Ubuntu on your chromebook, QGC will run :).

If the FPV goggles simply need an HDMI input like an external monitor, then the samsung 9 laptop will work. It has HDMI out.

I’ve been wondering what ROV FPV would be like for a while. How is it? Have you tried it from a boat? Does it make you nauseous?

Thank you for the input. I’m not going to linux-ify a chromebook that works for the OpenROVs

I’ve only used the FPV headplay googles a few times, and only on pool tests, but I thought they worked fine. (…and yes, Jacob, that was using a chromebook’s HDMI output.) Like you, I wonder if rough seas would make you nauseous while wearing goggles. @tciii has used my headset before on a pool test, so he can offer a good opinion as well.

Good question. I could blather on about how currents affect those things away from the intended collection point, the efficiency of collecting samples when you can see the target, or collecting under overhangs, or inside pipes. All of those would be lovely rationalizations, but the primary reason is that I teach a lot of biology for non-majors, and many of students start out thinking they don’t care about science…if I give them a controller and FPV goggles - game-ify water collection - there’s a good chance that I can get many interested enough in what they are doing to start to care WHY they are doing it.

I may start them out on underwater robotics, but I’m hopping they will care about some important issues in Florida when they are through with the class

1 Like

That is a perfectly valid reason :slight_smile:

I think you will love the BR2, easy to handle, easy to modify, easy to control and better images than most of the other small observation class ROV’s.

If you need different Niskin sizes, we have a suplyer here in Denmark KC Denmark A/S, KC Denmark · Oceanography · Limnology · Hydrobiology

Btw, how do you release the lid with the ROV?

alt-q ad alt-z in the OpenROV cockpit control the AUX wires, which I’ve attached to a servo.

This is important: If I can’t trigger this servo with a BlueROV2, there’s no point in getting one.

@jwalser, is anyone else triggering servos from a bluerov? Does QGroundControl have this ability? Does the BlueROV? Obviously, I want to trigger Niskin bottles, but there are other things we’d like to use servos for; e.g. sediment traps.

I am sure that Jacob can answer that :slight_smile:

@JoeyM You can control servos :).

Hi @JoeyM,

An important note- the waterproof servo you have linked there is IP67 rated, meaning that it is fine for brief immersion up to one meter deep. It is really meant for use on surface vessels where the servo may be splashed or otherwise briefly get wet, and not in environments where it will be under significant pressure for long periods of time.

-Adam

Thanks, @adam. I’m aware. We’ve been using the same servos (sourced from amazon) for a while.

I’ve had them below 15 feet and still functioning. A friend of mine has pushed them below 90 feet and still had them function. Yes, that kind of abuse will cause them to fail in the field eventually, but we can get some stuff done before they implode. You just treat them as a high priced consumable, make them easy to swap out, and carry spares. The one on the big niskin is held in by two zip ties.

If you made something like the waterproof servo that OpenROV used to sell, we’d gladly use that instead. (Yes, that’s a hint. You make the servo, I use it and make sure everyone knows where such a useful item came from.)

https://store.openrov.com/products/prototype-underwater-servo

I’ve never done it, but some folks will coat the seams of hi-tech servos with silicone and pack the area around the shaft with marine grease