**700 grms? **
That is a lot of buoyancy to counteract!
However, great progress, Geir! Do you consider the first test as highly successful? It certainly looks that way in the video.
You should try to implement some sort of video recording inside the case. I bet that you get some cool images from below the water.
It looks cool indeed. It
It looks cool indeed. It really surprise me the battery go underwater still working!
Filming underwater is not really clear with low-end camera. I tried to record underwater with GoPro but either the lake was too dirty that I can’t see anything further than 20CM or the camera wasn’t good enough.
It’s easier to add weight
It’s easier to add weight than flotation so that is no big issue. I’m reprinting the brackets that holds the battery so I get two M8 bolts on each side of to add weights. I have 10x 50x50x5mm steel plates that weigh 80g each so I can probably balance it pretty good.
So yes I’m happy with my first test run.
When it comes to video. I could probably split the signal that’s going to the monitor and record that. But that’s a bit in the future.
Thank you for your comments!
Hmm, I may have given you a bad salt to water ratio, or there’s more needed to simulate ocean water; here’s what I measure when I do it:
About 700mA, using certified Florida Gulf salt water. I remember more the first time I personally ran this test for someone, but I think the exposed wires were closer, which makes a difference.
More importantly, look at the wires after only 30 seconds of exposure:
And a few minutes back in the air:
That’s only 30 seconds of corrosion. Imagine the 30+ minutes I’m sure you would like to be down there. You will be replacing your battery and crimp connectors after every dive, if they even last that long. That 8.5 Watts of energy wasted is doing nothing but eating away at the exposed terminals till there is nothing left.
You can see (and hear) the reaction in this video: http://www.youtube.com/watch?v=1sAjw7vfNJ4
The reaction is almost violent, eletricity and salt water just don’t mix.
Not to mention and enviromental concern for what the reaction is putting in the water. Look at my cup of salt water now:
I’m not going to put that back in my fish tank, would you?
Here’s after a few hours of sitting, you can see all the junk left over from the reaction in the bottom of the glass.
Again, that was just 30 seconds. I don’t think that will be healthy for the fish and life where you want to operate your ROV.
I have taken your advice
I have taken your advice Madsci1016 and sealed up my contacts and added a waterproof plug. The Sugru that I have used will set in 24 hours and should make a waterproof seal around the contacts. I also added some Sugru where the cable goes into the plug.
The sealed contacts and connector look nice.
There’s been one photo of my latest project publically released. See http://twitpic.com/6kt9am
I’m working on getting a short video approved for release, but other then what you see, I can’t tell you anything about it. Such is life.
Features from commercial ROVs you may consider adding include a compass, which makes much easier to stay oriented; a depth sensor (same reason) and control loops that let you lock a heading or depth and it takes care of maintaining orientation while the operator putts around. Basic commercial ROVs usually have one more thruster on the bow aimed left and right. This lets you strafe left and right, so you can keep an object in view of the camera while you strafe up or down to see all of it.
Just some thoughts if you get the itch to upgrade it furthers.
Humm… I’d love to have a
Humm… I’d love to have a peek inside that hull and see what you guys are up to
It seems to be about the same size as the boat I built for my brother https://www.robotshop.com/letsmakerobots/node/21098 but the hull seems to be built for higher speeds than my displacement boat.
Thanks for your comments and input so fare. If I can make the ROV work using my current design I’ll probably leave that project alone. I’m working on something else that is under/over water and the plan is to use the same controlbox and monitor. This is still a bit too early to post, but I’m currently building fiberglass parts and we will see how that goes.
Video is up. Still can’t answer questions about it however.
Where did you get the water proof conectors?
It was somewhere on eBay but
It was somewhere on eBay but they were not that waterproof after all.