I am Buliding an ROV need some shield advice please

hi i have just started building an ROV (a kind of submarine that has a tether to transmit data)
i am new at Arduino and want to know if my idea will work before i purchase all the bits.
here is a list of what i plan to do

  1. control 3 electronic speed controllers with brush less motors.
  2. send information from a pressure sensor,2 temperature thermistors and an electronic compass trough the cat5 cable to my laptop
  3. to allow steering from a joystick plugged into the laptop
  4. to allow me to turn on and off 2 lights in the rov from the laptop
  5. control at least 3 other outputs from the laptop for a robot arm

i am planing on using a mega or uno as i have both i want to control the arduino trough a cat5 earth-net cable so will use an earth-net shield. i also want to overlay the sensor information on to the video signal as there will be a camera in the rovso will use a video development shield and was thinking of using a sensor shield to make connections easier.
my question is is this workable to use all these shields together and has it been done before and if so can any one help me sort it out.
thank you
Al :fearful:

Have you seen the OpenROV on kickstarter?
http://www.kickstarter.com/projects/openrov/openrov-the-open-source-underwater-robot

yes i have based my design on theirs but they are using a beagle board now and i need to use arduino
i am finding arduino hard enough as i am nearly 60 never mind trying to learn another system
Al

I would suggest using a MAX485 IC and serial (RS422/RS485) for communication to the ROV. It would be much less power hungry, less complex, and much cheaper than ethernet shields. Google will provide plenty of examples of how to use the MAX485 with the Arduino, and the EasyTransfer library makes the programming for the communication simple.