Annin Robotics AR4

$1,189 kit + motors/drivers

AvailablePython from a laptopMachined aluminumStepper-drivenROS 2DIY build

Possibly ≤ 1 weekShipping: Kit ships from the US, build takes days.

Remote control: Always tethered to a PC over USB: the official AR4 software drives it directly, and the community ar4_ros_driver exposes it to ROS 2 / MoveIt.

LEARN MORE (Official site) ↗

Overview

The best-known DIY 6-axis 'mini industrial' arm, successor to the AR2 and AR3 and used in many schools. Unlike servo hobby arms it uses belt- and gear-reduced steppers in an aluminum frame, giving real reach and payload for a desktop arm. The AR4 first appeared in early 2022 and went through five 'Mark' revisions. With the MK5 (2026), which swapped some limit switches for Hall-effect sensors, Chris Annin declared the hardware finished for the foreseeable future. Annin warns that cheap AliExpress AR3/AR4 clones are unauthorized counterfeits.

Type: Robot arm · Desktop & hobby arms
Maker: Annin Robotics (USA)
Released: 2022
Price: $1,189 kit + motors/drivers
Status: Available
Best for: Ages 16+
Programming: Open source (hardware + software)

Price and shipping

AR4 MK5 Robot Combo Kit (structure, machined aluminum parts, bearings, belts, hardware, primary electronics) is $1,189. The stepper motor, driver and power-supply package is bought separately from StepperOnline (about $730). Parts can alternatively be 3D printed.

Shipping: Kit ships from the US, build takes days. Kits are ordered direct from Annin Robotics in the US. Assembly and wiring are left to the buyer. Robot kits ↗

Specifications

Category	Robot arms · Desktop & hobby arms
Released	2022
Country	USA
Availability	Available
Programmability	Open source (hardware + software)
Built-in autonomy	None / scripted · Moves only when controlled, or plays preset motions
LLM support	Possible via SDK · Desktop software and community ROS 2 driver, no built-in LLM.
MuJoCo simulation	Community model · Ekumen's third-party ROS 2 stack includes MuJoCo sim packages. Ekumen-OS/ar4 ↗
NVIDIA Isaac simulation	Community model · Ekumen's third-party ROS 2 stack includes an Isaac Sim package (ar4_isaac). Ekumen-OS/ar4 ↗
Gazebo simulation	Community model · Third-party ROS 2 stacks with Gazebo bringup (Ekumen, ycheng517). Ekumen-OS/ar4 ↗
Best for	Ages 16+ (estimated)
Vision sensors	No vision sensors
Actuators	Stepper motors
Audio	No audio
Compute type	Arduino / ESP32 / microcontroller, Laptop / PC as the brain
Remote control	Python from a laptop
DOF	6
Reach	67 cm (26 in)
Payload	1.9 kg (4.15 lb)
Repeatability	0.3 mm
Weight	12.25 kg (27 lb), aluminum version
Controller	Teensy 4.1-based control electronics, host PC runs the control software
Sensors	Stepper motors with integrated encoders, Hall-effect homing sensors on J1–J3 and microswitches on J4–J6 (MK5)
SDK	Free AR4 desktop control software (teach pendant style), Python/Arduino-level source, community ROS 2 driver with MoveIt

Common questions

How much does Annin Robotics AR4 cost?

Annin Robotics AR4 is listed at $1,189 kit + motors/drivers. AR4 MK5 Robot Combo Kit (structure, machined aluminum parts, bearings, belts, hardware, primary electronics) is $1,189. The stepper motor, driver and power-supply package is bought separately from StepperOnline (about $730). Parts can alternatively be 3D printed.

Can Annin Robotics AR4 be bought today?

Yes, it is on sale. Kits are ordered direct from Annin Robotics in the US. Assembly and wiring are left to the buyer.

Who makes Annin Robotics AR4?

Annin Robotics AR4 is made by Annin Robotics (USA). It came out in 2022.

Can Annin Robotics AR4 be programmed?

Open source (hardware + software). Free AR4 desktop control software (teach pendant style), Python/Arduino-level source, community ROS 2 driver with MoveIt.