ST3215 Serial Bus Servo (19.5kg.cm, 7.4V, 360° Magnetic Encoder)

The ST3215 is a high-torque smart serial bus actuator engineered for multi-axis robotics, quadruped platforms, and robotic arms. It pairs a coreless motor and durable metal gear train with a 12-bit magnetic encoder to deliver high-resolution 360-degree positioning and continuous daisy-chain control. This makes it an ideal choice for makers, students, and engineers building sophisticated motion systems with simplified wiring.

High torque metal gear train

Delivering up to 19.5kg.cm of stall torque at 7.4V, the servo features a robust 1:345 reduction gear train constructed from copper and aluminium. The coreless motor assembly is housed in a durable PA+GF enclosure with dual-axis ball bearings for smooth operation under heavy loads.

12-bit absolute magnetic encoder

The integrated 12-bit magnetic encoder provides 360-degree absolute position sensing with 4096 steps of resolution (0.088 degrees per step) without the mechanical wear of potentiometers. It also supports multi-turn positioning across a range of plus or minus seven full rotations.

Daisy-chain UART serial control

Operating on a half-duplex TTL serial bus at up to 1Mbps, up to 253 servos can be connected and addressed individually through a single microcontroller port. This daisy-chain architecture dramatically reduces cable clutter and simplifies harness design in multi-joint robotic arms and walkers.

Four versatile operating modes

The servo can be configured for standard 0 to 360-degree angle control, closed-loop continuous rotation with constant speed under load, open-loop DC motor operation, or incremental stepping mode relative to its current position.

Real-time telemetry and protection

Built-in sensors stream real-time operational feedback including position, speed, load, operating current, input voltage, and temperature. Automated safety routines protect the servo by disabling torque during overload, overcurrent, overvoltage, or when temperatures exceed 70 degrees Celsius.

Built for advanced robotics

With a standard 25T output spline, low backlash under 0.5 degrees, and one-click centre calibration, the ST3215 is suited for humanoid robots, quadruped legs, robotic grippers, and automated sorting systems.