One thing you have to be very careful about when using encoders is slippage. Using encoders during autonomous mode when the robot is in minimal contact with objects that would cause traction lose (like other robots smashing into you
) is very useful, but when you move into a match setting your encoder derived position will slowly become less accurate due to slippage, sliding perpendicular to your drive wheels, etc.
One other solution is an ultrasonic sensor:
http://www.parallax.com/detail.asp?p...id=28015-5pack
One team has already posted a
PICTURE of their setup using this particular parallax model.
Other than that, your safest bet would probably be the camera
good luck with your rookie season!