The Knob Sense Cubelet by Modular Robotics is an individual magnetic block that will add manual control to a robot by allowing you to twist the knob and set the output value; twist counterclockwise for an output of zero and clockwise for a value of one.The Knob Cubelet features an embedded potentiometer and is an accessory for use in expanding your Modular Robotics Starter and Standard kits.The Knob Cubelet is part of the Sense family of Cubelets which are robotic blocks that act as inputs.These Sense Cubelets act similarly to how eyes and ears do for us and cause the robots they are part of to react based upon what they do and don't sense in the their surrounding environment.