November 13, 2014 AT 4:00 pm

Project Postmortem: Gael Langevin on InMoov Project #3DxRobotics #3DThursday #3DPrinting


Describe the specific project we will explore in detail.

InMoov project was initially started in January 2012 when I posted the first 3D printed hand on Thingiverse.

It all started after buying a FDM 3D printer for my work. As a sculptor, designer, I always need to create objects for my customers. I already had CNC machine, and getting a 3D printer seemed to be worth to try. My wife, wasn’t very favorably inclined to this machine, she was telling me that I could only produce little rabbits or Yoda’s figures. I had in mind that it could be used in a more practical and engineering way.

A big French company asked me to make a bid to create a futuristic prosthetic. The job didn’t happen, but I was thinking of using my 3D printer to create it.


I decided to design the prosthetic hand anyway on my free time. I always liked hands, my work shop is full with hands, made in all kinds of materials, some were molded with plaster on my own hands when I was 12 years old.

After designing and printing the first InMoov hand, which was a non-animatronic object , I decided to post it on Thingiverse under a CC-BY-NC Licence.

Sharing the parts with the Open Source community was a logical route for me. I have been using Linux for years, Blender as a 3D software as well, and my 3D printer was built following an open source project.


From that moment I had a lot of request coming from all over the world to transform that hand into a working prosthetic. I couldn’t accept that someone would use my project for an everyday-use prosthetic. I knew the plastic couldn’t handle it and I was thinking that it was better to buy one directly from a prosthetic constructor. I had no idea of the prices back then…

What I focused on, was to get the hand working with motors and my computer, since I had never used servo motors and electronic before, I did a lot of research and studies on the web to get a good idea how to get it to be animated. That is when I discovered Arduino, an Open Source microcontroller board.

I was then able to actuate the fingers with my keyboard using basic programming. See video:

At every stage of my progress, I would post on my blog and Thingiverse all my updates on the 3D files, including the code. That way, everybody could reproduce what was I was able to do.

That is how I created the InMoov community.

What Went Right?

At that point, in February 2012, I thought, “Let’s make a full 3D printed life size humanoid.”

Once I understood how a servo worked with an Arduino, I was then able to imagine other ways of using a servo motor. Extracting the potentiometer allowed me to use the power of those little motors in a complex arm movement.

So I started to work on the design of a shoulder and a bicep. It took me about a month to create the first shoulder and bicep. By april 2012, I was able to actuate it and post a video:

Although, I had known from the beginning of the design processes, I was working beyond human proportions. I printed all the parts and ran the first tests. I wanted to see if my design was viable. A sort of proof of concept.

Most of the people use servomotor as direct drive in robotics, which to me does not make sense, seems like a waste of torque. Since I didn’t want to buy expensive servos for my project, I had to think of another way to boost the torque produced by these little motors.

Designing wormgears was a good option. I lost speed, but by focusing on an in-between approach with my design, I was able to have enough speed and torque to lift the whole arm. Plus a power drill held up by the hand!

It took me a few months to redesign every part of the shoulder and bicep to make sure it would fit within human proportions. I was at the same time, following tutorials on Blender to perfect my knowledge. And also learning how to program using an Arduino.


In September 2012, I shared and posted all the parts for the bicep on Thingiverse. A lot of people were printing the InMoov hand, for various projects and emails were flowing in.

The InMoov community was growing and at the same time, my personal time was dwindling.

Mirroring 3D files is one of the fantastic things you can do in just a few clicks. From the right arm with hand, I was able to produce the left one for my robot.

Since I started playing with Arduino and servomotors, I was looking for a software to create gestures as easy as possible. Unfortunately, all the software I found were closed source and expensive. And most of them were totally incomprehensible for a beginner in robotics like me.


Doing my homework, surfing on the net, I finally stumbled on a software called MyRobotLab, it was Open and free, but yet difficult to understand. I decided to get in contact with the person behind it: Greg Perry. I explained to him my problem: having two arms, both operational with Arduino and motors, and how I wanted to synchronize them.

“No problem,” that’s what he said. I loved that answer!

From his point of view, he felt we should be able to do that and much more…

Our exchanges started in June 2012.

Gael Working on InMoov2

What Went Wrong?

The concept of the bicep is functional, but I’m not totally happy with it. Two things bother me since the beginning.

  • The restriction 90 degree angle of the forarm within the bicep is something that I have lately started to redesign.
  • The size and shape of the bicep is also something I want to modify.

With extra time I could certainly have done something better, but as I see it, many parts of the robot could be improved in a better model.

Since June 2013, I have been working on the design of a new hand, because the need for prosthetics is a fact. This new hand, includes all the motors, Arduino, drivers, and Advancer Technologies board within the palm. It has been a great challenge for me to pack all of those components inside the hand while still respecting human scale. Last August, I gave the first printed new hand to Nicolas Huchet. Because, he needs it, and because together, we should be able to produce an affordable prosthetic hand. See these two videos:

Creating and designing a functional robot for FDM 3D printing on my own and sharing it with the world, requires a LOT of time. I mainly work at night on this project because I have a full time job.

When I thought I would do a full size Humanoid robot, I had in mind to create a 3D printed sort of “Segway”, but obviously for the community, it is too simple… The people want legs on InMoov, so I have worked on a few designs.

I want to keep the same goal for the legs that I had for the upper body, affordable (less than $1500), easy to supply everywhere in the world, fast and strong. The challenge is ambitious! I have tried some low cost actuators with my design, but the results aren’t what I was expecting. Unfortunately, each time the community proposes the use of the same sort of actuators I have tried.

So I started to create a 3D printable actuator with low cost motors and materials. I have yet to build it for real and test it out…

Time is what I need…

How can someone get involved with InMoov?

Today, InMoov can be used in many projects like telepresence, prosthetics, flight learning, vision searching, object tracking, gesture recognition, voice control, EEG, robot and human interactions behaviors.

If you are looking at how to start on my project and you’ve never done any programming, you can 3D print the Finger Starter and follow the tutorial on my website.

When I create a 3D printed part, I design it to fit a 12cm-cubed print area, and in a way that you can print it on your machine without extra support. Every shape has to be thought through considering the process of 3D printing each part. I have seen few projects that have started after InMoov, but the parts aren’t designed to be printable on a home printer — you would need the services of a professional machine. And professional 3D printing is very, very expensive…

DSC 0036bis2

The goal of my project is to make it affordable for schools, universities, experts, artists, makers, anyone that has a 3D printer. Creating a robotic platform that anyone can learn and develop from. I think it is important for our future.

What is great with the community that evolves around InMoov. The fact that people are building it all around the globe. Points of views, perspectives and opinions are crucial. Together we can solve programming problems with faster results than closed source projects.

It is a undeniable force!

Inmoov robot arm 3d print208


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