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Pololu Romi Encoder Pair Kit — 12 CPR, 3.5–18V 

Add clean quadrature encoder feedback to your Romi mini plastic gearmotors, kit uses a magnetic disc + dual-channel Hall sensors to output A/B signals for direction + speed measurement—perfect for PID speed control, odometry, and “drive straight” robot builds.

  • 12 counts/rev of motor shaft: counting both edges of both channels gives 12 CPR (about 1440 counts per wheel revolution on the Romi).
  • Wide supply range: sensors run on 3.5V to 18V for flexible robot power setups.
  • Microcontroller-ready outputs: A and B are open-drain digital signals—pull up to your logic voltage (3.3V or 5V).
  • Compact & chassis-friendly: designed to fit neatly on the back of Romi motors without extending past the shaft.

Why/Benefits

Accurate robot motion
  • Closed-loop speed control (PID)
  • Odometry / distance tracking
  • Better straight driving + repeatable turns
Cleaner than optical encoders
  • Magnetic sensing (less sensitive to dust)
  • Simple A/B digital signals
  • Works across wide supply voltages

Technical specifications

Product Pololu Romi Encoder Pair Kit, 12 CPR, 3.5–18V (
Sensing method Dual-channel Hall effect + magnetic disc
Resolution 12 counts per motor shaft revolution (quadrature, both edges)
Supply voltage (VCC) 3.5V to 18V
Outputs A & B: open-drain digital (requires pull-ups to your logic voltage)
Connector pitch 0.1" (2.54mm) holes for common headers/connectors
Designed for Mini plastic gearmotors used on the Romi chassis

Pinout & installation notes

  • Mounting: designed to be soldered to the back of the motor (shaft passes through the board).
  • Motor pads: connect the motor leads to M1 and M2 pads along the board edge.
  • Power: VCC and GND power the sensors (3.5–18V).
  • Signals: A and B are open-drain—use pull-up resistors on your main controller board (or add optional 0603 pull-ups on the encoder board if needed).
  • Tip: If you want plug-in compatibility with Romi boards, orient the pins to face down toward the chassis; otherwise, wiring upward can be more convenient.

What’s in the box

  • 2× dual-channel Hall effect encoder boards
  • 2× 6-pole magnetic encoder discs
  • Low-profile header pins (for clean Romi chassis installation)

FAQ

  • Do the outputs work with 3.3V microcontrollers?
    Yes. Since A/B are open-drain, you pull them up to your logic voltage (e.g., 3.3V) using pull-up resistors.
  • Is this only for Romi?
    It’s designed around the Romi mini plastic gearmotor form factor, but you can adapt it to similar motors with a rear shaft if the mechanical fit works.
  • Do I need special cables?
    Not required. You can solder wires directly, use 0.1" headers, or use pre-crimped terminal wires for quick harnesses.

Romi Encoder Pair Kit, 12 CPR, 3.5-18V

Romi Encoder Pair Kit, 12 CPR, 3.5-18V

Low stock: 1 left

Product Code

POL3542

₱ 744.00
₱ 744.00
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