[ay2b]

Originally Posted by RoarRoar

I wonder, can I use others Speed Controller like this HB-25 Motor Controller from http://parallax.com, will this work on FRC Robot Controller. do i need to write code?

This is not legal for FIRST competitions, but it should work. The PWM output from an RC is the same PWM output used by standard R/C hobby receivers.

Originally Posted by RoarRoar

Can I connect a Digital compass to the FRC Robot Controller,how do this work,if this is possible.then i need a LCD display to view the number.

This depends on the type of digital compass. The easiest would be if you had one that outputted an analog value representing the direction; you could then just connect that to an analog input pin. Many people here, however, have reported various problems when attempting to use compasses. They apparently tend to be unreliable and noisy. There are a number of different ways of connecting an LCD screen. The easiest is probably to find one from www.sparkfun.com which is labeled as having a serial driver.

Originally Posted by RoarRoar

I will use the Robot Controller and Operator Interfac in a ROV (submarine)sow I most use two RS232 to RS485 converter, then I can use max 1200 metre cabel,I will hope this will work.

Let us know how it goes. Most people here are interested in robotics of all sorts, not just FIRST robotics. You might also contact someone from Team 842, Falcon Robotics, as they have done quite a lot with underwater robots.