Pololu 4860 / 4861 / 4862 / 4863 / 4864 / 4865 / 4866 / 4867 / 4868 / 4869 Metal Gearmotor 25D MP 12V with 48 CPR Encoder
Pololu 4860 / 4861 / 4862 / 4863 / 4864 / 4865 / 4866 / 4867 / 4868 / 4869 Metal Gearmotor 25D MP 12V with 48 CPR Encoder
Pololu 4860 / 4861 / 4862 / 4863 / 4864 / 4865 / 4866 / 4867 / 4868 / 4869 Metal Gearmotor 25D MP 12V with 48 CPR Encoder
The Pololu 4860-4869 series Metal Gearmotor 25D MP is a compact, high-torque brushed DC motor with integrated 48 CPR quadrature encoder, designed for precise motion control in robotics and automation applications. Professional engineers and hobbyists use this motor for autonomous navigation, wheeled robot platforms, and position feedback systems where accurate speed and distance measurement is critical. This product solves the challenge of obtaining reliable motor control with built-in encoder feedback without requiring external sensor integration.
Product Overview
The Pololu Metal Gearmotor 25D MP series combines a robust metal gearbox with a high-efficiency brushed DC motor and integrated quadrature encoder, delivering exceptional torque-to-size ratio. The 48 CPR encoder provides 192 counts per revolution when counting all four edges of the quadrature output, enabling precise odometry calculations and closed-loop speed control. The 25D form factor (25mm diameter) makes it ideal for space-constrained mobile robot designs while maintaining sufficient power delivery for real-world applications.
The different product variants (4860-4869) offer various gear ratios ranging from 30:1 to 1000:1, allowing selection based on specific speed and torque requirements. The 12V nominal voltage rating provides compatibility with standard battery packs and power supplies commonly used in robotics projects. The encoder output is directly compatible with microcontroller interrupt inputs and quadrature decoder circuits, eliminating the need for signal conditioning in most applications.
Key Specifications
| Specification | Details |
| Product Type | Metal Gearmotor with Integrated Encoder |
| Brand | Pololu Robotics and Electronics |
| Origin | Original/Authentic |
| Warranty | 7 days on manufacturing defects |
| Shipping | 1-5 days from Bengaluru |
| Delivery | 7-8 days across India |
| Support | 24/7 via Email and WhatsApp |
| Nominal Voltage | 12V DC |
| Encoder Resolution | 48 CPR (192 counts per revolution at quadrature) |
| Motor Diameter | 25mm (25D form factor) |
| Gear Ratio Options | 30:1, 50:1, 75:1, 100:1, 150:1, 200:1, 300:1, 500:1, 1000:1 |
| Output Shaft | 6mm diameter with D-cut flat |
| Encoder Type | Quadrature optical encoder |
Key Features
- Integrated 48 CPR quadrature encoder for precise position and velocity feedback without external sensors
- Multiple gear ratio variants enabling selection from high-speed to high-torque configurations for diverse robotics applications
- Metal gearbox construction providing superior durability and backlash resistance compared to plastic alternatives
- Compact 25mm diameter form factor optimized for mobile robot chassis integration with minimal weight penalty
- Direct microcontroller compatibility with standard GPIO interrupt pins for quadrature decoding
- Sealed encoder housing protecting optical sensors from dust and debris in field robotics environments
Applications and Use Cases
- Autonomous mobile robots requiring odometry for SLAM and navigation where encoder feedback drives distance calculation algorithms
- Wheeled robot platforms and differential drive systems where dual motors with synchronized speed control via encoder feedback ensures straight-line motion
- Line-following robots where encoder-based speed regulation maintains consistent velocity across varying terrain
- Robotic arms and actuators requiring closed-loop position control with encoder feedback for precise joint positioning
- Educational robotics projects including ROS-based platforms where encoder data feeds into motor control nodes
- Conveyor systems and material handling equipment requiring accurate speed measurement and synchronization
How to Use
To integrate the Pololu Metal Gearmotor 25D MP into your project, first select the appropriate gear ratio variant based on your required output speed and torque specifications. Connect the motor leads (typically red for positive, black for negative) to your motor driver output, ensuring the driver can handle the stall current at 12V. Mount the motor securely to your chassis using the mounting brackets, ensuring the output shaft aligns properly with your wheel or driven mechanism.
For encoder integration, connect the quadrature encoder outputs (typically labeled A and B) to interrupt-capable GPIO pins on your microcontroller. Configure your microcontroller to count rising edges on both channels to achieve 4x resolution (192 counts per revolution). Implement a quadrature decoder routine to determine motor direction and calculate velocity by measuring counts over fixed time intervals. For closed-loop speed control, use the encoder feedback in a PID control loop that adjusts motor PWM duty cycle to maintain target velocity. Ensure proper power supply capacity, as stall current can exceed 5A at 12V nominal voltage.
Frequently Asked Questions
What is the difference between the various Pololu 4860-4869 variants?
The variants differ in gear ratio, which determines the trade-off between output speed and torque. The 4860 (30:1) provides highest speed with lower torque, while the 4869 (1000:1) delivers maximum torque at reduced speed. Select based on your application: faster robots use lower ratios, heavy-load applications use higher ratios. All variants share identical encoder specifications and form factor.
How do I calculate the output speed and torque for a specific gear ratio?
Output speed in RPM equals motor no-load speed divided by gear ratio. Motor no-load speed is approximately 300 RPM at 12V for Pololu motors. For example, a 100:1 ratio yields 3 RPM output speed. Torque increases proportionally with gear ratio. Consult Pololu datasheets for specific motor torque constants to calculate exact output torque values for your selected variant.
Can I use this motor with PWM speed control?
Yes, the motor operates with standard PWM control from any motor driver supporting 12V DC motors. PWM frequency of 5-20 kHz is recommended to minimize audible noise and encoder interference. The encoder output remains independent of PWM duty cycle, so you can simultaneously control speed via PWM while monitoring actual velocity through encoder feedback for closed-loop control.
What is the maximum continuous current and stall current?
Continuous current depends on gear ratio and load, typically 100-300mA under normal operation. Stall current at 12V can reach 5-7A, so ensure your motor driver and power supply can handle peak current. Use a motor driver with current limiting or implement software-based stall detection using encoder feedback to prevent damage from sustained stall conditions.
How do I interface the encoder output with Arduino or Raspberry Pi?
Connect encoder A and B outputs to interrupt-capable pins on Arduino (pins 2 and 3 recommended) or any GPIO pins on Raspberry Pi. Use interrupt service routines to count pulses on both channels. Libraries like PIDController and quadrature decoders simplify implementation. For Raspberry Pi, use GPIO libraries like RPi.GPIO or gpiozero with edge detection callbacks.
When will I receive my order?
Orders are dispatched within 1-5 business days from our Bengaluru warehouse. Delivery takes 7-8 days to most locations across India.
What is your return and warranty policy?
We offer a 7-day return policy on manufacturing defects only. Contact support within 7 days of receipt for free replacement or full refund. Not applicable for user damage or misuse.
Are bulk discounts available?
Yes, wholesale pricing for orders of 10 or more units. Contact our sales team via WhatsApp or email for a customized bulk quote.
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Buy Pololu 4860 / 4861 / 4862 / 4863 / 4864 / 4865 / 4866 / 4867 / 4868 / 4869 Metal Gearmotor 25D MP 12V with 48 CPR Encoder Online in India
Purchase the Pololu 4860 / 4861 / 4862 / 4863 / 4864 / 4865 / 4866 / 4867 / 4868 / 4869 Metal Gearmotor 25D MP 12V with 48 CPR Encoder online at The Tech Depot, India's trusted source for genuine electronics. We deliver across Bengaluru, Mumbai, Delhi, Chennai, Hyderabad, Pune, Kolkata, Ahmedabad, Jaipur, and Surat. Get the best price on Pololu 4860 / 4861 / 4862 / 4863 / 4864 / 4865 / 4866 / 4867 / 4868 / 4869 Metal Gearmotor 25D MP 12V with 48 CPR Encoder with fast shipping and expert support.
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