Hi all, this is my first post here. I have a quick question for you guys:
I am currently building an underwater Remotely Operated Vehicle(ROV), and I have to interface several sensors in the ROV to a control station on the surface. I have a tether going from the ROV to the control station to carry signal data over an ethernet cable. I was going to interface the sensors to the arduino, and output the values on an LCD display.
My question is, would it be more practical to put the arduino in the ROV itself and run the wires for the LCD screen and the joystick controls up through the tether? Or should I put the arduino on the surface and run wires down to the sensors?
I am concerned about signal loss over the tether, as it is going to be around 100-150 feet long, and skinny wires. What do you think? Any input would be greatly appreciated. Let me know if you need more information.
It is probably best to put the arduino as close to the sensors as possible and then run a long serial link over UTP from the arduino to your base station, some serial interfaces like RS-422 can transmit at up to 100kbps at 4000 ft.
You could also use the ethernet shield and run ethernet over UTP back to your base station which would be faster but would be limited to 100m or 328ft.
You can also use USB but that is limited to 5m or 16ft per segment but you can get around that by using six 5m/16ft cables and 5 USB hubs to extend it to 30m ( max ) or 98ft.
Thank you for your prompt reply, gnu_linux. I think what you said will work, but in the meantime I just had another idea.
What if i had an arduino in the ROV and a second one in the base station? Would I be able to successfully run a serial connection between the first one and the second one? Then I would have more versatility in my final design.
Does this seem right to you? Let me know what you think.
I think the idea of using two Arduinos is a good one! I used to work on sonar systems, and we had a 500m tow-cable with optical fibres for communications and copper wires for power. It was wound onto a winch with optical slip-rings, if you can imagine such a gadget! We had seven transputers (parallel processor chips) in the "wet" end, and five more in the "dry" end, connected up to a Sun workstation for control and data storage.
Anyway, don't forget that there will be a voltage drop over the power supply lines in the cable, so you'll need to regulate power internally at the ROV end of the cable.
