This is a prototype I'm making as a demonstration for FIRST Tech Challenge teams. Most teams at this point use simple drawer slide mechanisms with string, which works well but often has reliability issues and doesn't take full advantage of the motor's power.

There's a few notable changes with what I'm building: the slide itself uses linear bearings and rods, which is lightweight, cheaper, and more commonly used in industry than drawer slides. Instead of string it uses belt, which doesn't risk getting tangled like string does, and allows the slide to be driven both forward and back. Finally, constant torque springs are used to make the slide neutrality buoyant. This takes advantage of the belt's two way movement to control the slide both extending and retracting, meaning the motor no longer needs to oppose the force of gravity, now just needing to deal with frictional losses and the force of acceleration, meaning much shorter times to extend and ret