Re: What switch can be pressed from both directions?
 

A triple echo?

A potentiometer or an encoder, depending on how your powering your system up and down, is what you would want to use here. You can count the rotations of the motor that powers your system with an encoder and do some math to convert that into distance traveled, and just tell the system to go to X height with a PID loop or something. Something similar can be done with a potentiometer.