---
title: "Waveshare ST3215 specs"
description: "Smart Servo actuator from Waveshare (Feetech OEM) (China). Peak torque 2.9 Nm, rated n/a, weight 69 g, torque density 42.6 Nm/kg, price $17."
canonical: https://actuatorlist.com/actuators/waveshare-st3215
last-updated: 2026-11-01T14:05:43.000Z
---
# ST3215 Serial Bus Servo (30 kg.cm) by Waveshare (Feetech OEM)

> Smart Servo actuator from Waveshare (Feetech OEM) (China). Peak torque 2.9 Nm, rated n/a, weight 69 g, torque density 42.6 Nm/kg, price $17.

## Specifications

| Spec | Value |
| --- | --- |
| Category | Smart Servo |
| Peak torque | 2.9 Nm |
| Rated torque | n/a |
| Max speed | 45 rpm |
| Gear ratio | n/a |
| Weight | 69 g |
| Torque density | 42.6 Nm/kg |
| Price | $17 |
| Price per Nm | $5.8 |
| 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=0.069,0.5,0&p=2): **30.3 N·m** at the shoulder with its 69 g at the elbow of a 2 kg-payload arm.

## Use cases

- robot arm
- quadruped leg

## Notes

Waveshare-branded Feetech STS3215-class magnetic-encoder bus servo, servo/motor mode switchable. Torque 30 kg.cm = 2.94 N.m @12V (19.5 kg.cm = 1.91 N.m @7.4V variant); no-load 45 rpm (0.222 s/60 deg) @12V; locked-rotor 2.7A. The Waveshare-branded unit is listed at ~68 to 69 g (heavier than the 55 g Feetech OEM). A faster ST3215-HS variant trades to ~20 kg.cm / 106 rpm. Used in Waveshare RoArm kits and LeRobot builds.

## Sources

- [https://www.waveshare.com/st3215-servo.htm](https://www.waveshare.com/st3215-servo.htm)
- [https://www.waveshare.com/wiki/ST3215\_Servo](https://www.waveshare.com/wiki/ST3215_Servo)
- [https://servodatabase.com/servo/waveshare/st3215](https://servodatabase.com/servo/waveshare/st3215)

## 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/waveshare-st3215
- Catalog index for agents: https://actuatorlist.com/llms.txt