About the Gripper

MSG gripper banner image

📖 Project overview

The MSG compliant AI stepper gripper is built around StepFOC stepper drivers, which enable precise FOC-based force control on standard stepper motors. This makes it well-suited for assembly tasks, human-robot collaboration, and AI data collection applications — including embodied AI, teleoperation, and VLA training — thanks to its camera-friendly design.

The gripper is modular in two key ways:

Option	Variants	Notes
Rail length	100 mm, 150 mm, 200 mm	Determines maximum grip span
Stepper length	21.5 mm, 40 mm, 60 mm	Determines maximum grip force output

All mechanical files, firmware, and software are open source, allowing you to attach a custom gripping tool and integrate the gripper with any robotic arm or platform.

⚒️ How to build / where to buy

You can buy the MSG gripper on our website: https://source-robotics.com/products/msg-gripper

If you want to source all parts yourself and build your own gripper, follow these steps:

Print parts from the STEP files folder based on your chosen configuration:

Rail Size	Folders to Print
100 mm	Common parts + Linear rail dependant parts/100mm rail + Stepper dependant parts/\<your stepper size>
150 mm	Common parts + Linear rail dependant parts/150mm rail + Stepper dependant parts/\<your stepper size>
200 mm	Common parts + Linear rail dependant parts/200mm rail + Stepper dependant parts/\<your stepper size>

Source all parts from the BOM
Follow the assembly video instructions to assemble your gripper
Follow the docs to get your gripper up and running

📚 Documentation

Resource	Description
Official website	Buy the MSG gripper or explore other Source Robotics products
DOCS	Getting started, wiring, configuration, and full API reference
Python API	Control the gripper from Python over CAN bus
BOM	Complete list of parts needed to build the gripper
Building instructions	Mechanical assembly walkthrough
URDF & MJCF files	Ready-to-use robot description files for ROS2, Gazebo, and MuJoCo
ROS2 package — MSG gripper	ROS2 driver and example nodes for the MSG gripper
ROS2 package — SSG48 gripper	ROS2 driver and example nodes for the SSG48 gripper (should also work with MSG)

💻 Quick start code example

import Spectral_BLDC as Spectral
import time

Communication1 = Spectral.CanCommunication(bustype='slcan', channel='COM20', bitrate=1000000)
Motor1 = Spectral.SpectralCAN(node_id=0, communication=Communication1)

Motor1.Send_Clear_Error()
Motor1.Send_gripper_calibrate()
time.sleep(4)

temp_var = 0
while True:
   if temp_var == 0:
      Motor1.Send_gripper_data_pack(50,100,700,1,1,0,0) 
      temp_var = 1
   elif temp_var == 1:
      Motor1.Send_gripper_data_pack(240,100,700,1,1,0,0) 
      temp_var = 0

   message, UnpackedMessageID = Communication1.receive_can_messages(timeout=0.2) 

   if message is not None:
      print(f"Message is: {message}")
      print(f"Node ID is : {UnpackedMessageID.node_id}")
      print(f"Message ID is: {UnpackedMessageID.command_id}")
      print(f"Error bit is: {UnpackedMessageID.error_bit}")
      print(f"Timestamp is: {message.timestamp}")

   time.sleep(3)