Rotary Encoder Module

This rotation sensor or incremental encoder (unlike a potentiometer) has no limit for several counts. It can also detect clockwise and counterclockwise rotation and that’s why it has 2 pins (SIA and SIB) for detecting rotation.

It translates the rotary motion into a sequence of pulse signals. By comparing the square wave generated from each of the two pins you can determine the direction of rotation (as shown in Figure below) and by counting the number of pulses you can determine both the rotation angle and the RPM of the rotating shaft. A reset button is provided to reset the counter to zero state when needed to restart counting.

Specifications:

• Operating Voltage:                       3- 5V
• No. of pulses per Cycle:             20 pulses
• NO. of Cycles:                               unlimited
• Reset Button:                             reset counts to Zero
• Rotation Direction Detection:   clockwise and counterclockwise
• Dimensions:                               32 x 18 mm

PIN Definition

• SIA (CLK):  Signal A (pulse) (output A)
• SIB (DT):  Signal B (pulse) (output B)
• SW: State of reset pin (0 or 1)
• VCC: voltage (3 – 5V)
• GND: Ground signal

Useful links

Rotary encoder datasheet and connection tutorial

Rotary encoder tutorial with Arduino