Feetech STS3215 Serial Bus Servo

The Feetech STS3215 (model ST-3215-C018) is a 30 kg.cm class programmable serial bus smart servo designed for robotic joints and precision actuation. It combines a coreless motor with a 1:345 all-metal gear train and a 12-bit non-contact magnetic encoder delivering 4,096 steps per revolution, enabling closed-loop position, speed, and torque control over a full 360 degrees without mechanical stops. Communication uses a half-duplex asynchronous TTL serial protocol (Feetech SCServo UART register map) at baud rates from 38,400 bps to 1 Mbps, allowing up to 253 IDs to be daisy-chained on a single bus. The firmware implements PID control and streams real-time feedback on position, velocity, current, voltage, temperature, and load percentage. Typical deployments include robot arm joints, humanoid legs, pan-tilt camera mounts, and multi-DOF manipulators where continuous rotation with absolute angle feedback is required.