IF (big IF) I were going to do this... here's where I would start...
1. Get a screw driver.
2. Open OI
3a. See what's inside...
3b. Look up the data sheets for the chips inside.
4. Pin out (w/ meter) what connects where and draw up
some kind of basic schematic. (Do this UNPOWERED)
5. Be happy.
Common stuff I would expect to be there (never having opened an OI).
A. Some kind of voltage regulation circuitry.
B. Some kind of microcontroller (probably another PIC18 series)
C. Some kind of RS232 driver circuitry.
Here's what people before you have noted about the Comp Port:
1. There are power and gnd pins.
2. There are some GPIO pins to control Auton/Disable
(GPIO is general purpose IO, think the digital inputs/outputs on the RC)
3. And the other pins are a mystery... but I'd bet there are
serial i/o pins, given how IFI has magically done away with
the radios directly connected to the OI.
Also from what I know about the Arena system:
The arena actually functions over ethernet (hardwired).
Each alliance station actually has a private IP address
(man... it was pretty cool to ping an alliance station
).
So here's the setup (on each side):
3 Arena Controllers somehow have an ethernet interface.
Each AC appeared to have 5 ports of interest:
1. 1 ports for Competition controllers
2. 1 Comm Port
3. 1 Power port
Now If I were a betting man (ie how i would design the system)...
I would use some kind of embedded linux to talk to a commercial
Single board computer that has a serial port (or 3, one for each AC)
over IP and relay data over some custom protocol over TCP.
Now... disclaimer. If you are not a CE/EE and know what you are doing
I would suggest not doing anything. Those things are darn expensive.
(I've never been brave/crazy enough to crack one open...one day maybe
and I'm a 5th year CE Grad Student)
Secondly, as a budding engineer you have to ask yourself what the
ethical implications of reverse engineering someone else's design are.
(I'm not touching this with a 10' pole)
Lastly, IANAL. Don't annoy IFI. Cease and Desist letters are not fun.
They do good work for FIRST.