This is an arduino rotation potentiometer , it is able to rotate upto 300-degree.  With the Arduino IO expansion board, in combination, it can be very easy to achieve position-dependent interaction with the rotating effect or produce MIDI instrument. So with this sensor you can learn how rotary potentiometer works and what analog signal is. You can have much fun with this basic input device.

Gravity Interface is adapted to allow plug&play.  The IO Sensor Expansion Shield is the best match for this sound senor connecting to your Arduino. As this sensor can work at 3.3V which make it compatible with Raspberry Pi, intel edison, joule and curie. 

Improvement List

• Wide voltage range from 3.3V to 5V
• Standard assembling structure (Times-of-5mm Center distance between two 3mm mounting holes)
• Easily recognitive interfaces of sensors ("A" for analog and "D" for digital)
• Icons to simplely illustrate sensor function 
• High quality connector
• Immersion gold surface

Rotating this sensor can input different voltage which can change Brightness of this LED. 

What is potentiometer?

"A potentiometer is an instrument for measuring the potential (voltage) in a circuit. A fraction of a known voltage from a resistive slide wire is compared with an unknown voltage by means of a galvanometer. The sliding contact or wiper of the potentiometer is adjusted and the galvanometer briefly connected between the sliding contact and the unknown voltage. The deflection of the galvanometer is observed and the sliding tap adjusted until the galvanometer no longer deflects from zero. At that point the galvanometer draws no current from the unknown source, and the magnitude of voltage can be calculated from the position of the sliding contact." 

Analog Rotation Potentiometer Sensor V1 For Arduino Related Projects:

How to Build A Smart Cooling Fan with Arduino?

SPECIFICATION

• Supply Voltage: 3.3V to 5V
• Interface type: Analog  
• 300 degree rotation sensor
• Size:22x31mm (0.87x 1.2 in)

DOCUMENTS

• Wiki (Analog Rotation Sensor V1)
• Schimetics

SHIPPING LIST

• Analog Rotation Potentiometer Sensor V1 x1
• Analog Sensor Cable (SKU:FIT0031) x1