---
title: "Feetech STS3215 C001 (7.4V, 19.5 kg.cm) specs"
description: "Smart Servo actuator from Feetech (China). Peak torque 1.9 Nm, rated 0.5 Nm, weight 55 g, torque density 34.7 Nm/kg, price $20."
canonical: https://actuatorlist.com/actuators/feetech-sts3215-c001
last-updated: 2026-11-01T14:05:43.000Z
---
# STS3215 C001 (7.4V, 19.5 kg.cm) by Feetech

> Smart Servo actuator from Feetech (China). Peak torque 1.9 Nm, rated 0.5 Nm, weight 55 g, torque density 34.7 Nm/kg, price $20.

## Specifications

| Spec | Value |
| --- | --- |
| Category | Smart Servo |
| Peak torque | 1.9 Nm |
| Rated torque | 0.5 Nm |
| Max speed | 52 rpm |
| Gear ratio | 345:1 |
| Weight | 55 g |
| Torque density | 34.7 Nm/kg |
| Price | $20 |
| Price per Nm | $10.5 |
| Backdrivable | n/a |
| Backlash | 30 arcmin |
| Voltage | 4.0-7.4 V |
| Peak current | 2.5 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=0.49&n=52): **2.67 W** of shaft power at its rated 0.49 N·m and 52 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

## Robots that use it

- [SO-101](https://actuatorlist.com/robots#therobotstudio-so-101) by TheRobotStudio: SO-101 is an open-source, 3D-printable arm designed by TheRobotStudio with Hugging Face as the successor to SO-100, with improved wiring and easier assembly. The follower arm uses six Feetech STS3215 serial bus servos (5 arm joints plus a gripper) at a 1:345 gear ratio and is usually paired with a leader arm for teleoperation and imitation learning in the LeRobot library. STEP and STL files, simulation models and a full bill of materials are published under Apache-2.0, and kits are sold by Seeed Studio, WowRobo, PartaBot and others.

## Notes

The 7.4V STS3215 build (SKU C001, 1:345) that TheRobotStudio specifies for the SO-101 follower arm; distinct from the 12V / 30 kg.cm STS3215. Feetech spec sheet: stall 19.5 kg.cm (1.91 N.m) at 2.5A and no-load 52 rpm (0.192 s/60 deg) at 7.4V, 16.5 kg.cm and 42 rpm at 6V; rated 5 kg.cm (0.49 N.m); 4 to 7.4V input; backlash 0.5 deg or less; 55g; copper gears, ball bearings, core motor. Kt 8 kg.cm/A. Half-duplex TTL bus at up to 1 Mbps with servo, closed and open loop wheel, and step modes. $20 at Seeed.

## Sources

- [https://www.seeedstudio.com/STS3215-19kg-cm-7-4V-Serial-Servo-p-6338.html](https://www.seeedstudio.com/STS3215-19kg-cm-7-4V-Serial-Servo-p-6338.html)
- [https://akizukidenshi.com/goodsaffix/STS3215-C001%20SEPC.pdf](https://akizukidenshi.com/goodsaffix/STS3215-C001%20SEPC.pdf)
- [https://akizukidenshi.com/catalog/g/g116312/](https://akizukidenshi.com/catalog/g/g116312/)
- [https://github.com/TheRobotStudio/SO-ARM100](https://github.com/TheRobotStudio/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
- [STS3215 (12V, 30 kg.cm) (Feetech)](https://actuatorlist.com/actuators/feetech-sts3215): 53.5 Nm/kg

## Machine-readable

- JSON: https://actuatorlist.com/api/v1/actuators/feetech-sts3215-c001
- Catalog index for agents: https://actuatorlist.com/llms.txt