Specification of Rotary Encoder Module:
Model: KY-040
Working Voltage: 5V
Material: PCB + Brass
Weight: 10g
Size: 32 x 19 x 30mm

 

The pin outs for this rotary encoder are identified in the below.
CLK: Encoder Pin A
DT: Encoder Pin B
SW: No Pushbutton Switch
+: 5V Supply
GND: Encoder Pin C

 

Pin connected to for Arduino:
CLK = [pin 3]
DT = [pin 4]
Button = [pin 5]
+ = [Pin 5V]
GND = [pin GND]

 

Pin connected to Raspberry Pi:
CLK = GPIO16 [pin 36]
DT = GPIO15 [pin 10]
SW = GPIO14 [pin 8]
+ = 3.3V [pin 1]
GND = ground [pin 6]