Joystick for Handicapped User

I have a student with a severe handicap in my Robotics class. He is only able to move his head left and right (he has no movement in his arm, leg, toes, etc.). I would like him to be able to move the robot. I was considering adapting a partner joystick somehow with a large push button.
Anyone ever tried something like that before?
This would be for classroom use and not for any vex event or competition.

I would keep to one thread. There is one with active answers.