Add quadrature encoders to your mini plastic gearmotors (extended back shaft version required) with this kit that uses a magnetic disc and Hall effect sensors to provide 12 counts per revolution of the motor shaft. The sensors operate from 2.7 V to 18 V and provide digital outputs that can be connected directly to a microcontroller or other digital circuit. This module is compatible with all of the dual-shaft mini plastic gearmotors we carry.
This kit includes two dual-channel Hall effect sensor boards and two 6-pole magnetic discs that can be used to add quadrature encoding to two mini plastic gearmotors with extended back shafts (motors are not included with this kit). The encoder board senses the rotation of the magnetic disc and provides a resolution of 12 counts per revolution of the motor shaft when counting both edges of both channels. To compute the counts per revolution of the gearbox output shaft, multiply the gear ratio by 12.
This compact encoder solution fits within the 11.5 mm × 22.5 mm cross section of the rear of the motors on three of the four sides. The fourth side of the encoder has the signal and power connections, and it extends 5 mm past the edge of the motor to leave room for mounting brackets. The assembly does not extend past the end of the extended motor shaft, which protrudes 5 mm beyond the back of the motor.
More detailed information at Pololu.