Rotary Potentiometer - 100k Ohm, Logarithmic (Panel Mount)
An adjustable potentiometer can open up many interesting user interfaces. With this rotary potentiometer just turn the dial and the resistance changes. This potentiometer from Bourns has a ¼" metal knurled shaft diameter, PC pin terminals, no detents, and has a 100K logarithmic taper.
Connect VCC to an outer pin, GND to the other, and the center pin will have a voltage that varies from 0 to VCC depending on the rotation of the pot. Hook the center pin to an ADC on a microcontroller and get a variable input from the user!