Aluminum structure, hardware, and primary electronics for the Mark 5 arm.
From $1,189
AR4-MK5The robot
The robot
anyone can build.
Open-source 6-axis arm for a desk. Machine the aluminum or print the parts, then program it in Python or ROS. Built for schools, shops, and makers who want industrial motion without the industrial price.
- Axes
- 6 DOF
- Reach
- 24.75 in
- Payload
- 4.15 lb
- Repeatability
- 0.25 mm
- Mass
- 27 lb
- Power
- 198 W
Who it's for
For industry
AR4 for Industry
Deploy the AR4 for light assembly, prototyping, or production tasks. Its Arduino/Python control and Modbus support bridge DIY projects and professional automation.
For education
AR4 for Education
From STEM classrooms to university labs, the AR4 teaches real-world automation with accessible Python programming and 3D-printable customization.
The film
The AR4 in motion
Applications
Same arm, many applications
Videos
See the arm move
How a build comes together
How to build your AR4
The combo is the core of the arm. Motors, a gripper, and covers finish it. Print the covers, or buy a finished set.
Robot kits
Start with the combo
- 01Combo
- 02Motors
StepperOnline motor, driver & power supply package
Factory directStepper motors, drivers, and power supply. Factory direct from StepperOnline.
- 03Gripper
- 04Covers
PETG covers and spacers in Black. Sold by C.I. Printing.
$299.98
Software
Python HMI, ROS 2, and a digital twin
Python HMI
Teach positions, jog in joint or Cartesian, run programs, and talk to the arm over a desktop interface. Dark and light themes. Resizable. Native Linux in 6.3+.
Teensy 4.1 kinematics
Motion math lives on a 600 MHz Teensy 4.1 so path following stays tight. An Arduino Nano or Mega handles 5 V grippers and solenoids in parallel.
Digital twin
Offline mode mirrors the real arm in 3D. Import STL workpieces, color the virtual robot, and debug programs with no hardware attached.
Xbox jogging
v6.2 added controller jogging and teaching plus Tool-Z jogging for precise flange work.
ROS 2
Community drivers from Chris Annin & Yifei Cheng (ar4_ros_driver) and Ekumen Labs. MoveIt 2, ros2_control, Docker.
Modbus, G-code, vision
Speak PLC. Stream G-code. Calibrate a webcam and pick taught objects with OpenCV, with no proprietary license.
In the wild
User builds
Real projects from workshops, labs, and makers.
AR4 Build of the Year
Vote for Build of the Year
One vote per account each year, and not for your own build. Entries close Nov 30.
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Builds in the running
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Votes cast
Ready to build
The kit. Free manuals. Open software.
Start with the combo kit, add motors and a gripper, print the covers, or buy a finished set. Everything you need to assemble and run the AR4 is documented.
