Servo Smart Serial STS3215, 360 degrees, 19kg, 12-bit Encoder, 7.4V

The smart servo STS3215 (code ST-3215-C001) is a high-performance solution for robotics applications requiring high precision, high torque, and full real-time monitoring.

Designed for a nominal voltage of 7.4V (Lithium 2S), this servo delivers a stall torque of 16.5 kg/cm at 6V and 19.5 kg/cm at 7.4V, with a nominal torque of 5 kg/cm, making it ideal for robotic arms, teleoperation platforms, and machine learning projects, including open-source configurations such as SO-ARM100 and SO-ARM101 (LeRobot).

The servo integrates a 12-bit magnetic encoder with 4096 steps per full rotation, ensuring an angular resolution of 0.088° and continuous feedback for position, speed, current, voltage, temperature, and load.

Control is achieved through a half-duplex TTL serial protocol, with configurable baud rates between 38400 bps and 1 Mbps, allowing quick integration with boards such as Arduino (via UART module + TTL adapter), Raspberry Pi, ESP32, or STM32, using standard interfaces compatible with Feetech or USB-TTL converters like the FE-URT-1.

The reinforced plastic housing (PA+GF) houses a coreless motor and a steel metal transmission with a 1:345 ratio, ensuring durability and stability in prolonged operation. The rotation angle is configurable within the range of 0 – 360° (0 – 4096 units), allowing both precise articulated movements and continuous operation mode.

The servo includes integrated protections against overheating, overvoltage, overcurrent, and overload, extending its lifespan under intensive usage conditions. Each unit can receive a unique ID in the range of 0 – 253, facilitating the control of multiple servos on the same serial bus.

Specifications:

Product code: ST-3215-C001, Feetech

Operating voltage: 6 – 8.4 VDC (nominal 7.4 V)

Stall torque at 6 V: 16.5 kg/cm

Stall torque at 7.4 V: 19.5 kg/cm

Nominal torque: 5 kg/cm

No-load speed at 6 V: 0.238 sec/60°

No-load speed at 7.4 V: 0.192 sec/60°

Encoder resolution: 12 bits (4096 steps/360°)

Transmission ratio: 1:345

Gear material: Metal (steel)

Motor type: Coreless

Rotation angle: 0 – 360° (configurable)

Communication protocol: Serial TTL, half-duplex

Baud rate: 38400 bps – 1 Mbps

ID range: 0 – 253

Feedback: Position, speed, current, voltage, temperature, load

Protections: Overheating, overvoltage, overcurrent, overload

Operating temperature: -20 – 60°C

Dimensions: 45.2 x 24.7 x 35 mm

Weight: ~55 g

Pinout:

The connector has 3 pins (2.54mm pitch), compatible with standard Feetech interfaces and USB-TTL conversion boards (e.g., FE-URT-1).

Usage:

Connect the servo to the power source respecting polarity: VCC to 6 V or 7.4 V voltage (recommended Lithium 2S battery) and GND to the circuit ground.

Since the servo uses half-duplex TTL serial communication (TX and RX on the same line), connecting to any control board requires a half-duplex adaptation module or circuit. Without this, communication will not function correctly.

Connect the servo DATA line to the half-duplex adaptation module, then link the module to the serial port of the control board (Arduino, ESP32, STM32, Raspberry Pi, or other compatible platforms).

For initial testing and configuration (setting ID, baud rate, limit angle), connect the servo directly to the PC via the FE-URT-1 module and the Feetech utility.

Install the SCServo library in the chosen development environment (Arduino IDE, Python, etc.).

Assign a unique ID to each servo (default ID 1) before connecting multiple units on the same bus to avoid communication conflicts.

Upload the test program, verify the servo’s response, and monitor feedback parameters (temperature, current, load) to prevent overloading.

Package contents:

1 x STS3215 Servo

1 x 3-pin connector cable (15 cm)

1 x Servo accessories pack