RoArm-M2-S

What is the RoArm Series?

The Waveshare RoArm family includes two product lines — the M2 (4-DOF) and M3 (5+1-DOF) — both built on carbon fiber and 5052 aluminum alloy. A 360-degree omnidirectional base combined with flexible joints creates a workspace spanning over one meter in diameter. The innovative dual-drive shoulder design doubles joint torque while maintaining high repeat positioning accuracy through 12-bit magnetic encoders.

The M3 extends the M2 kinematic chain with a 2-DOF articulated wrist (pitch + rotation), enabling more dexterous end-effector positioning at the cost of some payload capacity. Both lines share the same ESP32 MCU, the same JSON command protocol, and the same WiFi/ESP-NOW/serial/HTTP control interfaces. The M3 additionally supports LeRobot for ML-based teleoperation.

Four models, one protocol

This documentation covers the RoArm-M2-S, M2-Pro, M3-S, and M3-Pro. All share the same ESP32 control board and JSON command set. The “-S” models use plastic-housing servos; the “-Pro” models upgrade to all-metal housings. See the comparison table for details.

Lightweight Build

Carbon fiber and 5052 aluminum alloy. M2 under 850g, M3 under 1050g. Mounts on mobile platforms with ease.

Dual-Drive Shoulder

Two servos on the shoulder joint double torque output. M3 adds a 2-DOF wrist for dexterous manipulation.

JSON Control Protocol

Simple JSON commands over HTTP, serial, or ESP-NOW. Every joint, axis, and function is addressable.

ROS2 + LeRobot

ROS2 workspace with MoveIt2 and Gazebo. M3 adds LeRobot support for ML-based teleoperation.

Quick Links

WiFi Configuration Connect via AP, STA, or combined mode

Arm Control Guide Joint angles, XYZ coordinates, and speed control

Step Recording Record, edit, and playback motion sequences

JSON Command Reference Complete T-code reference from firmware source

Specifications

Parameter	M2-S	M2-Pro	M3-S	M3-Pro
Degrees of Freedom	4	4	5+1	5+1
Servos	5× ST3215 (plastic)	5× ST3235 (all-metal)	7× ST3215/HS (plastic)	7× ST3235 (all-metal)
Servo Torque	30 kg.cm @ 12V	30 kg.cm @ 12V	30 kg.cm @ 12V	30 kg.cm @ 12V
Wrist	Single axis (EoAT)	Single axis (EoAT)	2-DOF (pitch + rotation)	2-DOF (pitch + rotation)
Weight	826g ± 15g	873g ± 15g	973.5g ± 15g	1020.8g ± 15g
Payload	0.5kg @ 0.5m	0.5kg @ 0.5m	0.2kg @ 0.5m	0.2kg @ 0.5m
Workspace	1090mm × 798mm	1090mm × 798mm	1120mm × 798mm	1120mm × 798mm
Repositioning Precision	≈ ±4mm	≈ ±4mm	≈ ±5mm	≈ ±5mm
Encoder Resolution	0.088° (12-bit)	0.088° (12-bit)	0.088° (12-bit)	0.088° (12-bit)
MCU	ESP32-WROOM-32	ESP32-WROOM-32	ESP32-WROOM-32	ESP32-WROOM-32
Communication	WiFi, ESP-NOW, Serial, HTTP	WiFi, ESP-NOW, Serial, HTTP	WiFi, ESP-NOW, Serial, HTTP	WiFi, ESP-NOW, Serial, HTTP
Power	12V / 5A (3S LiPo)	12V / 5A (3S LiPo)	12V / 5A (3S LiPo)	12V / 5A (3S LiPo)
LeRobot Support	—	—	Yes	Yes
ROS2 Support	Yes (Humble)	Yes (Humble)	Yes (Humble)	Yes (Humble)

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Documentation consolidated from the Waveshare Wiki and RoArm-M3 Wiki. Hardware and firmware by Waveshare.