While laptops eventually become past their prime, many of the underlying bits and pieces are still functional and could be reused. If you’re wondering what to do with an old touchpad, especially one with a Synaptics chip, then this stepper motor control project should provide some inspiration.

Here the touchpad is read by an Arduino Leonardo using a PS/2 library, which translates these finger swipes into stepper signals via a driver board. 

When the user scrolls forward or backward, the motor responds either with a nice natural acceleration/deceleration motion, or the ability to move to a certain set point with a tap.