[EricH]

Originally Posted by MICHAELABICK

Solenoids are illegal to use on an FRC robot for anything other than pneumatics

They were, through the 2011 season, that I can recall.

The 2012 rulebook, however, includes the following:

[R46]
Each power-regulating device (speed controller or relay module) shall control one and only one electrical load (motor, actuator, electric solenoid, or compressor).

[R48] J. electrical solenoid actuators, no greater than 1 in. stroke and rated at no greater than 10 watts continuous duty
at 12V,

Also see [R50].

Now, as to what the 2013 rulebook has, I'm as in the dark as you are, so we'll see if they're legal or not.