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Another newbie question: payload swapping in the field


#1

[Moderator: is this is in the wrong location, please feel free to move it. Apologies in advance; I’m still learning the ropes around here.]

Hi All,

I have another newbie question. What method do you use to change, add or remove BlueROV2 payloads in the field? On the OpenROV we’re using three wire LED connectors for the three AUX wires, and it works fine. Here’s a photo of the setup. You can see that we’re also using a two wire waterproof LED connector for the tether.

If we want to add a water sampler to the ROV, we just unscrew the white connector, plug in a servo powered payload, screw it shut, and go back into the water. It is easy, fast, and can be done on the deck of a boat. I’m sure that BlueROV is using something that is more durable and rated for deeper depths, but I haven’t heard anything about exactly what you guys do or how long it takes. Exactly how do you folks change payloads on the BlueROV2s. Is this something you do in the field? How long does it take?


(Jacob) #2

On the BlueROV2, there are three penetrator blanks that you can replace with cable penetrators. Switching out the cable penetrators would be possible but not exactly easy peasy on a boat. It takes about 10 minutes. However, if you put one of those waterproof connectors in the cable penetrator, then the process would match what you are used to.

As far as wiring, the Pixhawk has connectors for servos and relays, and you can use the Pixhawk or the Raspberry Pi for serial devices.


#3

@jwalser
A 10-minute switch out is impressive. I end up having to disconnect most of the wires between the aft endcap and electronics module in order to have sufficient access for the penetrator wrench. Breaking everything down and reassembly takes me the better part of an hour. Am I a missing a trick or just less practiced than you? A youtube video could be helpful.


(Jacob) #4

You can get a penetrator on/off without disconnecting all of the electronics by using a penetrator wrench on the outside, and a needle nose on the inside. It is very tight on the inside though, so it is a bit difficult.


#5

OK, so it sounds like swapping penetrators is non-trivial and time consuming. If I want to add and remove payloads in the field, my best bet is running a three wire waterproof LED connector through a penetrator and doing the swaps outside the penetrator.

Is that an accurate take home?


(Jacob) #6

Yes. My guess would be that those connectors would be the weak link in your depth rating. What depth have you taken those to? Do you have a link?


#7

Yes. My guess would be that those connectors would be the weak link in your depth rating.

Understood. That makes perfect sense

What depth have you taken those to?

I’ve only taken them to 20’ or so. A friend of mine has gone deeper.

Do you have a link?

I’m using the ones discussed - and linked to - here:

I know I’ve said this before, but if Blue Robotics built a servo and a connection for it that were rated for better depths, I’d definitely be purchasing them.


(undersearobotics.com) #8

I have some connectors very similar to those. I suspect that they are only waterproof when connected (male to female). I haven’t tested this but that might be something you might want to consider.


#9

I suspect that they are only waterproof when connected (male to female).

Yes, that’s true. It is the reason we made a female plug to attach when not carrying a payload.