Homebuilt ROVs Forum

Hi,

I want to build an Rov as a school project with my pupils to enter an inter-school competition, but I have no experience at all.

We'll be using plastic pipe to build a frame, 12V bilge pumps for propulsion and be controlling and powering the robot via a wired umbilical. The challange will most likely involve retrieving something from the bottom of a swimming pool.

Looking at my book, 'Build your own Underwater Robot' by Harry Bohm and Vickie Jensen, it seems that there are two main designs for novices: the Seaperch, and the slightly more involved Seafox (I'm hoping that these names will mean something to you). Neither of these will be too difficult, though simplicity is always to be desired. Total budget is $480 (£300), though we have been supplied with a camera and monitor.

My question is which design should we go for? What advanteges does the Seafox offer over the simpler Seaperch?
Any other advice will be most appreciated.

Many thanks,
Ewan.

I think you will be better off with something along the lines of the Seafox over the Seaperch. The Seaperch is just a very basic Rov and just meant to get your feet wet, while the Seafox can be modified to suit your mission needs.

The one thing I would recommend though is running Converted bilge pumps (pumps with props), this will give you more power and you can get away with a minimum of only 3 pumps which will be save you a lot in the budget department. You can also just buy bilge pump replacement cartridges which are usually cheaper too.

-Steve

Thanks,

I intend to go for the most powerful 12V pump I can find, What size of prop do you recommend. Too small will lose power and too big migh blow a fuse. I think my total current budget is 8 Amperes. I was going to just take a stab at 50mm props and mix left hand and right hand ones where they will be working in pairs, is this necessary?

Cheers.

8 amps will only support 2 thrusters operating at the same time. that is a pretty small power budget.

by left and right in pairs do you mean counter rotating props? I use and recommend counter rotating props. imo, they do make a difference.

Hey,
I purchased that book 2 years ago and built the Seafox Rov. I used a milk crate and 6 - 600 gallon per hour bilge pumps from ebay. I zip tied the four bilge pumps to the corners and then took another milk crate and cut the bottom out of it and zip tied it in the center of the other milk crate.To the middle one i zip tied the up and down bildge pumps. I then hooked up all the bilge pumps to a cat 5 networking cable which ran to a board with 6 regular light switches. For the ballast I used a small water bottle zip tied to the top of the middle piece.To make neutrally buoyant I filled the water bottle with a little water. For power I hooked the whole thing up to a truck that was turned on. I was able to drive it around and have it dive and surface. I ran it in someones pond. I have since decided to build a more complex one. The Seafox Rov is very basic but from building it you can learn how it operates and moves and then it will inspire you to build better and more complex ones.

happy building!

Alex

Why the need for sutch powerful thrusters? Smaller motors allow you to use rc hobby parts for kort thrusters and are more efficient. If this vessel is designed for waters without current and there is no extreme time limit for the mission you could save amps and money.

As for retrieving an object try something outside the box like a balloon filled with baking soda that you squirt water into to surface with the objective in your vessel's claw. Good luck sounds like fun!

Yeah I see your point, I am wanting to build my next one without bilge pumps, the seals leak in fresh water, it will rust if water goes to the motor. The bilge pump will seize, hence why I only have two bilge pumps left. I want to use some other motors like the ones you suggested the Kort motors. I need something reliable and something that will not need much maintenance and will last longer and also cheap .

Alex Stuart

Alaska ROV Systems