---
title: "Feetech STS3215 (12V) specs"
description: "Smart Servo actuator from Feetech (China). Peak torque 2.9 Nm, rated n/a, weight 55 g, torque density 53.5 Nm/kg, price $16."
canonical: https://actuatorlist.com/actuators/feetech-sts3215
last-updated: 2026-11-01T14:05:43.000Z
---
# STS3215 (12V, 30 kg.cm) by Feetech

> Smart Servo actuator from Feetech (China). Peak torque 2.9 Nm, rated n/a, weight 55 g, torque density 53.5 Nm/kg, price $16.

## Specifications

| Spec | Value |
| --- | --- |
| Category | Smart Servo |
| Peak torque | 2.9 Nm |
| Rated torque | n/a |
| Max speed | 45 rpm |
| Gear ratio | 345:1 |
| Weight | 55 g |
| Torque density | 53.5 Nm/kg |
| Price | $16 |
| Price per Nm | $5.4 |
| Backdrivable | n/a |
| Backlash | n/a |
| Voltage | 6.0-12.6 V |
| Peak current | 2.7 A |
| Communication | TTL |
| Control modes | position, velocity |
| Encoder | 12-bit magnetic absolute (4096 steps, 360 deg) |
| Integrated driver | yes |
| Availability | in production |
| Data status | Catalog headline specs spot-checked: confirm revision |

## Size a joint

- [Motor torque calculator](/tools/motor-torque-calculator?solve=power&t=2.94&n=45): **13.9 W** of shaft power at its peak 2.94 N·m and 45 rpm.
- [Robot arm torque calculator](/tools/robot-arm-torque-calculator?L=0.4,0.35,0.12&m=1.2,0.8,0.3&a=0.055,0.5,0&p=2): **30.2 N·m** at the shoulder with its 55 g at the elbow of a 2 kg-payload arm.

## Use cases

- robot arm
- quadruped leg

## Notes

The default actuator of the LeRobot SO-ARM100/SO-101 arms. Stall torque 30 kg.cm = 2.94 N.m and no-load 45 rpm (0.222 s/60 deg) quoted at 12V; a common 7.4V variant gives ~19.5 kg.cm = 1.91 N.m. Ships in multiple gear-ratio SKUs (1:147 C046, 1:191 C044, 1:345 C001/C018). Half-duplex TTL serial bus, position + wheel (velocity) modes.

## Sources

- [https://www.feetechrc.com/products/serial-port-series-steering-gear-page-3](https://www.feetechrc.com/products/serial-port-series-steering-gear-page-3)
- [https://www.robotshop.com/products/feetech-12v-30kgcm-magnetic-encoding-servo-sts3215](https://www.robotshop.com/products/feetech-12v-30kgcm-magnetic-encoding-servo-sts3215)
- [https://github.com/TheRobotStudio/SO-ARM100](https://github.com/TheRobotStudio/SO-ARM100)
- [https://shop.wowrobo.com/products/feetech-sts3215-servo-12v-30kg-high-torque-servo-for-so-arm100](https://shop.wowrobo.com/products/feetech-sts3215-servo-12v-30kg-high-torque-servo-for-so-arm100)

## Similar Smart Servo actuators

- [PH54-200-S500-R (Dynamixel-P / Pro+) (Robotis (Dynamixel))](https://actuatorlist.com/actuators/dynamixel-ph54-200-s500-r): 85.4 Nm/kg
- [STS3250 (12V, 50 kg.cm) (Feetech)](https://actuatorlist.com/actuators/feetech-sts3250): 65.8 Nm/kg
- [XM540-W270-T (Robotis (Dynamixel))](https://actuatorlist.com/actuators/dynamixel-xm540-w270-t): 64.2 Nm/kg
- [XH540-W270-T (Robotis (Dynamixel))](https://actuatorlist.com/actuators/dynamixel-xh540-w270-t): 60 Nm/kg
- [H54-200-S500-R (Dynamixel PRO) (Robotis (Dynamixel))](https://actuatorlist.com/actuators/dynamixel-h54-200-s500-r): 52.3 Nm/kg

## Machine-readable

- JSON: https://actuatorlist.com/api/v1/actuators/feetech-sts3215
- Catalog index for agents: https://actuatorlist.com/llms.txt