Feetech ST3215 C001 C044 Servo

DESCRIPTION

The Feetech ST3215 is a professional-grade, high-torque smart servo designed for advanced robotics applications. Operating on a Serial Bus communication protocol, this servo allows for the daisy-chaining of multiple units, significantly reducing wiring complexity in multi-axis systems like humanoid robots, hexapods, and robotic arms. This listing covers two gearbox variants — the C001 (1:345 gear ratio) and the C044 (1:191 gear ratio) — which share the same smart electronics, 12-bit magnetic encoder, and TTL serial bus interface, and differ only in gearing, torque, and speed.

Advanced Smart Features

Unlike traditional PWM servos, the ST3215 functions as a smart node within a network.

• Daisy-Chain Topology: Connect up to 253 servos in a single line, utilizing only one data pin from your controller (Arduino, Raspberry Pi, or ESP32).
• Programmable Protection: Built-in safeguards for over-temperature, over-voltage, and stall protection to prevent hardware failure during high-stress maneuvers.
• Real-Time Telemetry: Monitor the internal state of each joint in real-time, enabling closed-loop control and predictive maintenance.
• DIY-Friendly Mounting: Features a standard 25T spline and multiple mounting points compatible with standard brackets.

Choosing a Variant

• ST3215-C001 (1:345): Higher gear reduction for maximum holding torque at low speed. Best for humanoid leg joints and static load-holding applications.
• ST3215-C044 (1:191): Lower gear reduction for faster motion with strong torque. The reference servo for the LeRobot SO-ARM101 robotic arm.

APPLICATIONS

• Humanoid Robotics: Ideal for hip, knee, and ankle joints requiring high holding torque.
• Quadruped Robots: Precision movement and shock resistance for robotic "dogs."
• Robotic Arms: The C044 is the reference servo for the LeRobot SO-ARM101, well-suited for accurate, repeatable joint motion.
• Industrial Automation: Small-scale pick-and-place machines and grippers.
• Educational Platforms: A cost-effective alternative to high-end industrial servos for university-level mechatronics.

TECHNICAL DETAILS

• Operating Voltage: 6V - 8.4V (rated 7.4V)
• Encoder Type: Integrated 12-bit magnetic encoder for absolute position feedback without physical wear
• Communication: TTL Serial Bus (up to 1Mbps) allowing for bi-directional feedback on temperature, load, speed, and voltage
• Gear Train: Hardened steel gears paired with a robust aluminum alloy middle case for superior heat dissipation

ST3125-C001

• Gear Ratio: 1:345
• Torque: 16.5kg.cm (6.0V) / 19.5kg.cm (7.4V)
• Speed: 0.238s/60° (6.0V) / 0.192s/60° (7.4V)
• Primary Use: High-torque holding joints

ST3125-C044

• Gear Ratio: 1:191
• Torque: ~27.4 kg.cm stall / 9 kg.cm rated (7.4V)
• Speed: 0.137s/60° (6.0V) / 0.116s/60° (7.4V)
• Primary Use: High-torque holding joints

SHIPPING LIST

• 1x ST3215-Servo
• 2x Servo Horn
• 18x Screw
• 1x JST Wire