Made for DIY and Prototyping

3d printable Open Robotic Actuator. Designed for DIY and Prototyping purposes. Contains the minimal number of non-3d printed parts. Among the required non-3d printed parts are just bearings, screws and threaded rivets, widely available on any market.


With 1:80 input/output torque ratio the actuators ensures the torque of 6.5 n*m for Nema 17HS4401 stepper motor or 10.5 n*m for Nema17HS6001 stepper motor. That is enough to build the robotic manipulator with 500-600 mm reach and 0.5kg of payload.

Closed Loop

The actuator is designed to use AS5600 12-bit absolute position Hall Effect encoder, that helps to keep track of the actual position of the actuator. This allows to programmatically compensate the mechanical deformation and backlash, determine when the actuator stucks due to excessive load or train the manipulator by moving it with your hand.


The Arduino and python source code for the firmware and the python library required to programmatically control the actuator are available on github.


The FreeCad 3d design files, bill of materials and assembly instructions are available here:

ORA-3. Assembly Manual
This post contains the step-by-step guide on how to assemble the 3d printed robotic actuator ORA-3. It covers only the mechanical operation, electronic components soldering and programming are not covered here. 3D Printed Parts List #Part NameImageQuantity 1ORA-3 Body 1 2ORA-3 Cover…


Ratio 1:80
Max Torque 10.5 n*m
Efficiency 60 %
Motor Type Nema 17
Input Shaft Diameter 5 mm
Output Shaft Diameter 45 mm
Dimensions 150 x 120 x 55 mm
Weight 280 g