Well I haven't had time to complete this project yet, but it is on my very long list of summer projects. Here's my plan:
- camera power - use Vex motor port to camera power input - standard PWM cable.
- pan servo power - use 2nd Vex motor port to pan servo - standard PWM cable.
- tilt servo power - use 3rd Vex motor port to tilt servo - standard PWM cable.
- data connection - I planned to use the three wire RS-232 port on the camera out to the IFI TTL driver circuit just like on the full size FRC controller with a standard PWM cable. There is a schematic for the TTL driver at IFI here. The TTL drivers are available through IFI at $10 or you can build your own with components from Mouser, Digikey, or Jameco (sorry RadioShack doesn't stock the RS-232 driver chip) for about the same price. Modify two very short PWM cables. Tie the +5v (red) together from the Vex controller RX/TX ports and connect to the +5v (pin #4) on the TTL driver. Tie the two Gnd (black) together from the Vex controller RX/TX ports and connect to the Gnd (pin #1) on the TTL driver. Then take the signal (white) wires from the Vex controller RX/TX ports and connect to the TX and RX (pins #2 & 3) on the TTL driver respectively. Remember transmit from the camera would be receive on the controller and camera receive would be transmit on the Vex controller. Keep the TTL connection to the Vex controller very short. Use two sided foam tape to hold the TTL driver on the top of the Vex controller case.
Then comes the coding. I haven't even started thinking about the code yet.
I'm considering using two Vex batteries connected in parallel to give longer working time. The camera drained the standard 7.2v backup batteries rather quickly.
This is the start of my plan, again I haven't had time to try it yet. Good Luck.