Hardware specifications
Mechanical fabrication
- Printing cost: roughly €50 for a follower arm, €105 for a leader–follower pair within the EU when outsourcing prints.
- Materials: PLA+ by default; PETG or nylon for higher temperature tolerance, >35% infill on load-bearing links.
- Follow the official STL pack and BOM in the SO-ARM100 repo; check the LeRobot Discord for community upgrades (metal joint inserts, cable harnesses).
Actuation and electronics
| Component | Notes |
|---|---|
| FEETECH STS3215 servos | Follower arm: six identical servos (7.4 V/20 Nm or 12 V/30 Nm). Leader arm gears: 3× 1/147 (C046), 2× 1/191 (C044), 1× 1/345 (C001). |
| Servo bus adapter | Waveshare Serial Bus Servo Driver Board with USB-UART bridge. |
| Debug tools | Official FEETECH Windows software, FT_SCServo_Debug_Qt, and soarm_sdk's own Viser dashboard. |
| Power | 7.4–12 V DC, sized for peak current (~6 A per arm). Match barrel jack polarity (5.5/2.1 mm or 5.5/2.5 mm). |
See Servo Control Table for the STS3215's full register map (EEPROM vs. SRAM, what each address means) — useful reference if you're debugging at the register level rather than through the dashboard.
Sensing and peripherals
- Cameras: UVC webcams, Intel RealSense D405/D435, or any RGB-D sensor supported via
LeRobot camera adapters; calibrate with this workspace's own
camera_calibrationpackage. - IMU: M5StickC/ESP32 boards via
imu_sdk, mounted on the wrist for inertial feedback in the teleop loop.
Compute, networking, and safety
- Control workstation: Ubuntu 22.04 LTS or macOS ≥12, 8+ CPU cores, 16 GB RAM; an NVIDIA GPU if training
diffusion/RL policies locally (required for
soarm_mjlab's CUDA path). - Safety: hardware e-stop, safety relay, over-voltage protection; power servos down before swapping end effectors.
Calibration and troubleshooting
- Homing vs. kinematics: LeRobot's calibration routine sets a consistent zero; for accuracy-critical geometric calibration from motion capture or camera data, use the FIGAROH toolbox.
- Serial bus baud rate mismatches — confirm both controller and servos agree (some adapters top out below 1 Mbps).
- Mixed firmware revisions — update all servos to the same version before chaining them.
- Power polarity mistakes — double-check barrel jack wiring before powering up.