Magnetic Encoder Pair Kit for Mini Plastic Gearmotors (12 CPR, 2.7–18V)

Turn your mini plastic gearmotor into a “smart” motor with real feedback. This Pololu magnetic encoder kit adds quadrature encoders to mini plastic gearmotors with extended back shafts, using a magnetic disc + Hall effect sensors to produce 12 counts per motor-shaft revolution (counting both edges of both channels).

To get counts per revolution at the gearbox output shaft, multiply your gear ratio by 12.

Fit & clearance notes

Designed to fit within the motor’s rear profile on 3 sides; the connection side extends about 5mm for bracket clearance.
The assembly does not extend past the end of the extended back shaft (which protrudes about 5mm).
Extended back shaft required (this won’t work on standard single-shaft motors).

Installation note: This system is intended for users comfortable with physical installation. The encoder board is meant to be soldered directly to the back of the motor, so take care to avoid prolonged heating of the motor pins.

Why/Benefits

Closed-loop ready: measure speed/RPM, distance, and direction using quadrature A/B signals.
Wide sensor voltage: Hall sensors run from 2.7V to 18V and output digital signals suitable for microcontrollers.
Cleaner signals: built-in comparator hysteresis helps prevent spurious transitions near stop points.
Compact build: magnetic disc + tiny board fits neatly behind the motor.

Technical specifications

Model	Magnetic Encoder Pair Kit for Mini Plastic Gearmotors
Compatible motors	Mini plastic gearmotors with extended back shafts (dual-shaft version)
Encoder type	Dual-channel Hall effect sensors + 6-pole magnetic disc (quadrature)
Resolution	12 counts per revolution of motor shaft (counting both edges of both channels)
Output shaft counts	Output CPR = (gear ratio) × 12
Sensor supply	2.7V to 18V (VCC)
Outputs	A & B digital outputs with on-board 10kΩ pull-ups to VCC; hysteresis included
Connection pitch	0.1″ (2.54mm) pad pitch
Installation	Encoder board solders to motor pins; disc presses onto back shaft

Pinout & power notes

Motor pads: M1 and M2 pads connect to the motor leads.
Encoder pins: VCC, GND, A, B are used to power the sensors and read quadrature outputs.
Logic level: A/B pull up to VCC, so choose VCC to match your MCU input tolerance (e.g., 3.3V for ESP32).
Wiring: pads are 0.1″ pitch—use standard 2.54mm connectors/headers or solder wires directly.

FAQ

Will this work with my mini plastic gearmotor?

Only if your motor has an extended back shaft (dual-shaft version). Standard single-shaft motors are not compatible.
How many counts do I get at the gearbox output?

Multiply your gear ratio by 12 (e.g., 100:1 gearbox → 1200 counts per output revolution).
Can I run it on 3.3V logic?

Yes—power VCC at 3.3V so A/B pull up to 3.3V (recommended for ESP32/RP2040).

Magnetic Encoder Pair Kit for Mini Plastic Gearmotors, 12 CPR, 2.7-18V

Name: Magnetic Encoder Pair Kit for Mini Plastic Gearmotors, 12 CPR, 2.7-18V
Brand: Circuitrocks
SKU: POL1523
Price: 744.0 PHP
Availability: InStock