Rule R12, Just make sure you watch out for it.

[Canop3n3r]

R12 Physical ROBOT elements created before Kickoff are not permitted. Exceptions are:

A. OPERATOR CONSOLE,
B. battery assemblies per R4,
C. FABRICATED items consisting of one COTS electrical device (e.g. a motor or motor controller), connectors, and any materials used to secure and insulate those connectors

Please note that this means that FABRICATED ITEMS from ROBOTS entered in previous FIRST competitions may not be used on ROBOTS in the 2015 FRC (other than those allowed per R12-C). Before the formal start of the FRC Build Season, Teams are encouraged to think as much as they please about their ROBOTS. They may develop prototypes, create proof-of-concept models, and conduct design exercises. Teams may gather all the raw stock materials and COTS COMPONENTS they want.