Annin Robotics (USA) Annin Robotics AR4 (1)

Annin Robotics (USA) Annin Robotics AR4 (2)

$1,189 kit + motors/driversAR4 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.

AvailablePython from a laptopMachined aluminumStepper-drivenROS 2DIY build

Possibly ≤ 1 weekShipping: 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 ↗

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.

Official site ↗Specs FAQ ↗ROS 2 driver ↗

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.

Specifications

Category	Robot arms · Desktop & hobby arms
Released	2022
Availability	Available
Programmability	Open source (hardware + software)
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