This linear slide potentiometer comes with an added kick - its not just a plain old slide pot! Underneath is mounted a slim geared DC motor that can gently move the wiper up and down, without human interaction. Often seen in very fancy A/V control panels, you could use these as linear feedback sensors for light robotics, or for interactive controls that can be controlled digitally as well as manually.

The potentiometer side and the motor side are electrically separate. The pot presents as a classic 3-pin resistor divider. The motor is a 2-pin 5V~10V DC motor that requires a full H-bridge motor driver to control both forwards and backwards. When there is no voltage on either of the motor pins, the slider is free to move manually.
There's also a 'touch 'pad that is electrically connected to the metallic slider, that you could connect to a capacitive touch sensor for detecting touch (this assumes that any slider knob you add on is metallic or conductive) We stock a capacitive-touch conductive slider knob here.
So, say if you want to move the slider to the middle, your code will have to read the potentiometer analog voltage while slowly powering the motor one way or the other until the analog reading reaches the desired spot, then 'release' the motor!

Comes as one motorized slide pot - H-Bridge controller is not included, any Arduino-like microcontroller will do the job nicely.