STS3215 vs Dynamixel XL330
The Feetech STS3215 is the stronger and cheaper servo: 19.5 kg.cm stall at 7.4V (30 kg.cm for the 12V version) for about $20, against 0.52 N.m (about 5.3 kg.cm) at 5V for the XL330-M288. The XL330 wins on size, weight (18 g) and software polish, so it suits leader arms, wrists and grippers, while the STS3215 suits load-bearing joints.
What matters
- Torque: STS3215 C001 is 19.5 kg.cm at 7.4V; XL330-M288 is 0.52 N.m (5.3 kg.cm) at 5V; XL330-M077 is 0.215 N.m.
- Voltage: STS3215 comes in 7.4V and 12V classes; XL330 runs at 5V (3.7 to 6V) and dies on 12V.
- Size and weight: XL330 is 20 x 34 x 26 mm and 18 g, much smaller than the standard-size STS3215.
- Gears: XL330 uses engineering plastic gears; STS3215 uses metal gears in a plastic case.
- Encoder: both give 4096 steps per turn.
- Software: XL330 speaks Dynamixel Protocol 2.0 with ROBOTIS's SDK and Wizard; STS3215 uses Feetech's bus protocol, well supported in LeRobot.
- Price: STS3215 about $17 to $22; XL330 about $27 at ROBOTIS US and EUR 40 in Europe.
Our picks
| Pick | Why | Where to buy |
|---|---|---|
| Feetech STS3215 7.4V (C001) Load-bearing joints on a budget | About 3.7 times the stall torque of an XL330-M288 for less money; the default in SO-101 and LeKiwi. | Seeed Studio: $20.00 Waveshare: $16.99 single; $16.99 to $21.99 across 7.4V and 12V options OpenELAB: EUR 23.57 |
| Feetech STS3215 12V More torque from the same body | 30 kg.cm at 12V when 19.5 kg.cm is not enough. | Seeed Studio: $22.00 RobotShop: $31.71 |
| DYNAMIXEL XL330-M288-T Light joints, compact grippers, Koch builds | Small and light, with the Dynamixel toolchain. Koch v1.1 uses it in the follower's wrist and gripper. | ROBOTIS: $27.49 (unverified) single; backordered in snippet Generation Robots: EUR 40.20 RoboSavvy: GBP 27.20 |
| DYNAMIXEL XL330-M077-T Hand-moved leader arms | Low 77.5:1 gearing makes it easy to back-drive by hand; 383 rpm no-load at 5V. Too weak to hold a follower arm. | Generation Robots: EUR 40.20 RoboSavvy: GBP 22.19 |
FAQ
Can I put STS3215 and XL330 servos on the same bus?
No. They use different protocols and different voltages. You need a Feetech bus adapter for one and a ROBOTIS U2D2 (or similar) for the other, each with its own supply.
Which one is more reliable?
Both hold up in LeRobot builds. The most common XL330 failure in builder reports is feeding it 12V; the most common STS3215 mistake is buying the wrong gear ratio.
Is the 12V STS3215 a drop-in for the 7.4V one?
Mechanically yes, same case and horns. Electrically it needs a 12V supply, so do not share a supply with 7.4V servos.
Why does LeRobot list both?
Koch v1.1 was designed around Dynamixels; SO-100 and SO-101 later switched to STS3215s to cut cost. The software supports both buses.
Sources: emanual.robotis.com · emanual.robotis.com · www.waveshare.com · www.seeedstudio.com · www.seeedstudio.com · github.com · huggingface.co · github.com