Help with choosing a control system for my ROV

[rvanscotter]

I talked to them too, they sell run off at a 10% discount. Those pieces range from 50-125' if you get the 2300 cable is $2.70/ft but thats not a neautral bouyant cable. The real price hits when you want the cable connectors and terminators. If you have them terminate and seal the connectors its an additional $300 plus the connectors. I was seriously thinking that on my final design I would get a nice 50m tether, realistically it will about $700-$1000 when it's all said and done. That's a big tag!

[bikerbones1968]

I agree. Way more than I want to spend on a tether. I am confident I can terminate any cable without leak issues. A neutrally buoyant tether in my mind is a must. Trying to achieve that with regular cat5e, or similar twisted pair cable and a bunch of foam pieces and zip tie straps is not my idea of ideal.

I am meeting with the owner operator of AUROA ROVs located about 100K from my location in Halifax next week. I get to test drive their new demo unit in the Halifax harbour. It will be nice to see and operate a professionally built ROV. I did mention to Jim, the owner, I am still looking for a tether solution and perhaps I can get one through them at cost. Never hurts to ask while I am on site playing with a new toy.

[CLYON]

Hi i'm a newbie building my first ROV. I guess like everyone starting out I am trying to decide on how to control it. Most of my other questions have already been answered by reading post on this site. The two ways I am looking to control are A VEX 6 channel TX RX and Arduino Uno to Arduino Uno. Both would satisfy my needs for now. Also I am going to use onboard batteries so I will have all the pairs in the Cat 5 cable to use. Here are my questions.

With the VEX, how far a run of cat 5 cable will it go using the tether port? From what I have read it seems like people are using it with no problem, but I need to be sure.

With the Arduino to Arduino, what is the best way to be connected to communicate? Do I have to have any other circuitry to make it work through the cable? Thanks.


Chuck

[fluxno]

With the Arduino to Arduino, what is the best way to be connected to communicate? Do I have to have any other circuitry to make it work through the cable? Thanks.

if you're running a long tether, the best way is to use RS485 or RS422. for RS485(2-wire half-duplex) you'll need some extra code to have a RTS signal to shift the communication direction. I think there are some code pasted on the forum for this. you'll guaranteed find it on the arduino forums.
you will need a RS485 driver chip ie: https://www.sparkfun.com/products/10124

with RS422 or RS485-4wire(Full duplex) you dont need any special code, other than normal serial comunication, just stick a MAX488 on each serial output and a 120ohm resistor on both of the reciever sides.


both rs485 and rs422 will give you possiblilities to have great lengths of cable. and the complexity gives if you can have/need 2 or 4 lines for communication.
rs485 2wire can have up to 4000ft/1200meter cable under ideal conditions
rs422/rs485-4wire can have up to 4900ft/1500meter

if you dont need bi-directional communication between the arduinos you can use rs422 over 2 wires instead of 4.

[CLYON]

That will work. I was thinking at first I would have to have an expensive USB or Ethernet extender to travel any length. That would have pointed me back to the VEX. Still can't make up my mind though, but if I had all the answers what fun would that be. Thanks.


Chuck