P 126

Overview

Pololu Model 126 is a Dual Motor Driver Shield designed for Arduino Mega platforms, based on the Maxim MAX14870 integrated circuit. The shield provides dual H-bridge motor control with a continuous current rating of 2 A per channel and peak currents up to 3.6 A. It operates within a supply voltage range of 4.5 V to 36 V. The design integrates comprehensive protection features including overcurrent, overtemperature, and undervoltage lockout. It utilizes direct Timer1 register manipulation to generate 20 kHz PWM signals, optimizing efficiency and reducing audible noise. The board includes dedicated fault detection pins and supports software-based direction inversion via library functions.

Feature Summary

• Integrated dual-channel H-bridge driver with built-in current sensing and diagnostic capabilities
• Direct hardware timer integration for precise high-frequency PWM generation independent of standard analogWrite abstractions
• Robust fault management system utilizing latched error states and atomic register operations for deterministic control

Applications

• Dual-wheel differential drive mobile robot chassis control
• Precision pan-tilt mechanism actuation requiring smooth acceleration profiles
• Automated linear actuator systems in embedded environments

Procurement Notes

Verify the specific revision level of the Pololu 126 shield when sourcing components, as hardware revisions may alter pinout compatibility or component placement. Ensure the accompanying DualMAX14870MotorShield library version matches the firmware requirements of your target microcontroller architecture. Confirm that the power supply meets the 4.5 V to 36 V input specification to prevent undervoltage lockout or damage to the onboard regulation circuitry.

Selection Notes

Select this shield when driving two DC brushed motors from an Arduino Mega platform requires higher current capacity than standard L293D-based shields offer. It is suitable for applications demanding silent operation due to its 20 kHz switching frequency. Consider this option if the project benefits from integrated thermal and current protection without external discrete components. It is not compatible with Arduino Uno due to specific Timer1 dependency and form factor constraints.

Part Context

The Pololu 126 serves as a specialized expansion board within the RepRap Arduino Mega Pololu Shield (RAMPS) ecosystem lineage. It bridges the gap between low-level microcontroller GPIO control and high-power motor actuation. By encapsulating the MAX14870 complex driver logic, it simplifies the development of motion control algorithms for hobbyist and educational robotics projects.

Replacement Considerations

For single-motor applications, consider the Pololu Single Motor Driver Shield. For higher current requirements exceeding 2 A continuous, evaluate the Pololu High-Power Motor Driver series. Alternative platforms using different microcontrollers may require custom driver circuits as the 126 is optimized specifically for the Arduino Mega pinout and timer architecture.