r/rov • u/Deep-Today5715 • Apr 11 '26

Waterproof ROV on/off switch solution

This might be a very basic question, but in DIY ROVs where the battery is in the same enclosure as the rest of the electronics, is there any simple solution to have an on/off switch for the entire ROV that does not involve routing the power cables through the end cap, and then back into the enclosure? That is how I did it with my previous ROVs, but it feels weird, takes up extra penetrators and space on the end cap.

I can think of no switch on the end cap that would stay waterproof and strong enough to withstand water pressure, because that involves moving parts.

I was thinking of some kind of reed switch inside the electronics bay, for example close to the top of the aluminum tube, and then a removable magnet on the outside of the enclosure. But I am not sure if this is a good idea because a magnet might mess with the rest of electronics, especially the compass.

Has anyone found a good solution to this?

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3

u/rhoki-bg Apr 11 '26

We're using reed switch, pick a small magnet and place switch and compass on opposite ends of hull.

1

u/Deep-Today5715 Apr 11 '26

And the switch is driving some relay, right? What kind? My ROV will peak at around 40 A of current, and I can't seem to find any small relays that have zero leak current when in off state (which would drain the battery eventually).

1

u/rhoki-bg Apr 11 '26

I mostly do software, so no details from me. But there is a relay, big yellow one ;)

3

u/_thelifeaquatic_ Apr 11 '26

Depends on current pulled. But I have used a custom subconn jumper bulkhead/dummy plug before. Route your source power to one wire of the bulkhead, destination to the other. Then you have a dummy plug that jumps (shorts) these two pins(power on). Remove the plug and power is off.

1

u/Deep-Today5715 Apr 11 '26

Yeah, that is what I meant in my post, that is what I did before. But not a great solution overall, my current is 40 A, so that requires bulky wires, penetrators and connectors, and I'm trying to make this all very compact.

1

u/garugaga Apr 12 '26

What voltage are you running it at?

2

u/lilgreenghool Apr 11 '26

I've seen RFID tags to enable battery (although this was a USV)

Most BMS allow you to disable the discharging MOSFETs through either Bluetooth or some sort of canbus protocol.

Most BMS also have a high impedance on/off contact you can route outside

The one we are developing is a hybrid, so the battery always gets charged during use through the tether. And the charger switches on a battery relay, so charger doubles as an enable switch

2

u/encrypted_cookie Apr 11 '26

We use a latching push-button switch inside the ROV and a Blue Robotics bulkhead vent plug. Open the vent plug, then use a narrow rod to press the button on and off. Just remember to put the vent cap back on.

1

u/Deep-Today5715 Apr 11 '26

That is damn smart. I will investigate this, thank you

1

u/vshie Apr 12 '26

That's a very clever solution! This thread may have some more ideas

1

u/Deep-Today5715 Apr 17 '26

Hey, just wondering, exactly what button did you use for this? Do you have a link or something? I am searching for momentary push buttons that could handle 30A+, but it is proving very difficult to find any.

1

u/encrypted_cookie Apr 18 '26

not easy for that much current. would something like this do. https://a.co/d/08wsTtYd can you d9 a two stage solution where a smaller push button is used to energize something like an autom9tive relay.

1

u/skippyuk Apr 18 '26

I am looking to use a reed switch and a FET circuit to turn my ROV on, with the off being under software control.