Building a shoulder and torso

All right let see how we’re going to proceed. In this tuto we are going to build the shoulder and torso simulteanously. I would have rathered do it separatly, but my pictures were already done this way, and I’m not going to take the robot apart for to make new pictures.

Here is the list of parts and the number of prints needed for the torso:

Here is the list of parts and the number of prints needed for 1 right shoulder:


Follow the step1 in “Building the bicep of InMoov” for to extract the potentiometers of your servos.

Here is another solution posted by an InMoov builder (Wayne Kinne) if you can’t open up your servo the way I did it, of course if you have a solder pomp, it will be even easier:

Or you can also watch these videos posted by a InMoov builder (by Kaibab):

Here is another set of videos (by Yann Huguenin), in which the technique involved is to remove the solder on the three motor connections, leaving the motor in place instead of romoving it:

Or this video:



There is a difference though in the last part during re-welding the cables to the potentiometer depending if you build the right or left shoulder.

Weld the cables this way, if you are building the right shoulder. In this picture the blue replace the green or the black wire depending on your servos.

Weld the cables this way, if you are building the left shoulder. In this picture the blue replace the green or the black wire depending on your servos.


This will allow your servo to turn the opposite way making your initial 0 position becoming your 180 position. And your initial 180 position become your 0 position. I hope you get the idea. This will be done on both servos used in each the shoulder. Now let start the assembly.

If you plan on building both shoulders you should repeat most of the following steps explained bellow.

Remove the pre-built support under “PistoBaseV4″
Make sure “PistonClaviV2″ can run freely inside. If your prints are a bit too tight you can ease it with grease. I had to fine tune my printer for those parts to get the right setting.
Assemble together with your favorite pliers, “PistoBaseV4″, “ClaviBackV1″ and “HomPlatback+V1″.
If you are building in PLA, you can use a hot air gun to get parts warmed up to get them to fit easier, it avoids braking parts.
Make sure that “PistoBaseV4″ can rotate smoothly.
Add “HomPlatback-V1″to “HomPlatback+V1″
Here you can see my favorit pliers in action.
Add “ThroatHoleV2″ to “HomPlatback-V1″to “HomPlatback+V1″
“ThroatHoleV2″ has been modified since this picture.
Time to assemble the front. Mount together “SternumV1″ to “ClaviFrontV1″.
Sorry this picture shows the first version I made but it’s pretty close, check the next picture.
This is the shape you will obtain with the last version and the last “ThroatHoleV2″ in the back.
Mount together the two “ThroatLowerV1″ and “ServoHolsterV1″.
This servo, set in the middle of the torso, is for to move the head up and down and can be added later if you wish, but the holster should be set already in place.
Mount this assembly to the back assembly. Check on the picture the plots and the position of the servo. Front clips and back clips are different.
Add the front assembly to the rest.
You can help yourself with clamps. It should all fit nicely. You can add acetone to glue parts together, but I haven’t done it yet and it holds together since a few weeks of tests.
Now assemble “PivGearV2″ to “PivCenterV1″
It should turn in it smoothly but without slack.
Using a fear amount of grease is a good idea.

Ok, This section with green parts is the same than for the bicep so I re-used the pictures and changed the name of the parts. This picture is to show you what is the angle position of “PivCenterV1″ compared to “PivMitV1″. Check the little rectangle hole where the potentiometer will go.

So keeping the same rotation angle, mount “PivmitV1″ to “PivgearV1″.

I used clamps to make sure there wouldn’t be slack between all three parts during pre-screwing. Leave them like this, we will screw them definitly together in a further step.

Attach one servo to “PivcenterV1″. For to do so: mount but don’t tight fit the white actuator wheel.

Once the servo is attached, you can tight the screw.

Clean up the support on “PivWormV1″

Mount “PivWormV1″ to the actuator with 4 little screws, make sure they don’t come out behind the actuator, otherwise you have to cut them. I made it operate a few turns by plugging the servo on the Arduino. Then I cleaned up the dust created by the parts.

Before closing the case with “PivTitV1″, make sure you used a good amount of grease, every where on the gears. (sorry the servo is not mounted on this picture)

Mount the two “ConnectorV1″ to “RotTitV1″ and “PivMitV1″, making the junction between the bicep and the shoulder.
Glue with acetone all three parts together, and do it well, this is going to take a lot of pressure.
This is how they should be positionned. (sorry this picture is after everything is built)
Set “PivGearV1″ in this rotation angle to “PivMitV1″. Here have a close look at angle of the hole of the potentiometer inside “PivGearV1″. (sorry the screws of the next step are already mounted on this picture)
Use a longer screw to assemble “PivGearV1″ to “PivMitV1″ to “RotTitV1″
Use a clamp to make sure there is no slack between the parts during mounting.
Then screw “PivGearV1″ to “PivMitV1″ on the sides and top.
Put together the two “ServoHolderV1″ and “ServoHolsterV1″
Mount the assembly to “PivTitV1″. Glue well with acetone, this is going to take pressure too, but make sure the “ServoHolsterV1″ can rotate freely.
Set in the potentiometer into “PivPotentioV2″ and clip it as is.
Here make sure the welding for the right shoulder. Red wire being on top, yellow in the middle, and blue on the bottom. I used hot glue on the weldings to avoid short circuits.
Mount with screws”PistonClaviV2″ to the white wheel of your servo. set your servo into “ServoHolsterV1″ with screws.
Attach the complete arm to the shoulder parts.
In the back of the shoulder clip the first part of “PivPotHolderV2″ to “ClaviBackV1″
Remove the two screws attaching the servo and put in place the second part of “PivPotHolderV2″.
Use long screws to go through the servo holes. Fix the potentiometer in place as is.
You can see on this picture I used “arduinosupport” from the hand to set my Board.
Fix the bolt to complete the attachement of thearm to the shoulder.
You are now set to GO for your first test. One thing you should keep in mind is that the servo actuating “PistonClaviV1″ should stay between 0 and 80 position, if you go further it will certainly break. Now if you use InMoov service from Myrobotlab, this is aready implemented to avoid breakage. Remember to do your test in a large space, and check your wires so they don’t get torn off.

Setting up your InMoov to defaults

Script to learn how to use MyRobotLab with the Arm and shoulder.

Setting “omoplate” servo and potentiometer to default “Rest” position 10 on a range from 0 to 180

To reach this value you may have to rotate slightly your potentiometer in it’s bracket.

When omoplate is at default 10 position there is no gap between these two parts

See video for the omoplate movement:


Setting “shoulder” servo and potentiometer to position 33 on a range of 0 to 180.  It is not the default position for “rest” but this way, we can align the two servos seen from the back of InMoov.

To reach this value you may have to rotate slightly your potentiometer in it’s bracket.

See video for the shoulder movement:


Setting “rotate” servo and potentiometer to default “Rest” position 90 on a range of 0 to 180.

Align the parts as shown on the pictures.

To reach this value you may have to rotate slightly your potentiometer in it’s bracket.

See video of the “rotate” servo movement:

Comments 33

    • Profile photo of Gael Langevin

      Mmmmh, yes that might a problem. Did you use the rectangular pot holder from Thingiverse? I don’t have rectangular pots, other wise what shoud be done is to modify the file to make sure the pot is correctly positionned once mounted. But it will imply creating a left and a right pot holder.

  1. Profile photo of Thomas Wurm

    in omoplate and biceps i have the round poti but when i ordert the next servos i have got the newer version with the rectangular poti
    and so i do it just with a dremel and glue the potentiometer with hot glue but that was not the best solution.
    i think about to create a holder with only the round hole for the poti so that you can rotate the poti in right position and a second part like a clamp wich is screwed and holding then the poti in right position

  2. Profile photo of David

    Hi, wanted to ask, ThroatHole that is available to print now is a bit different from the one on here, how is the new ThroatHole attached the sticks that are attached to the HomePlate Back are longer then the ones on the previos should they be sticking out or?

  3. Profile photo of zurczurc

    Dear Gael
    I´m been working the shoulder and the biceps of the InMoov. I´m using other servos, the CYS-S8218 Digital 6V-7.2V Metal Gear 40KG Torque Servo. Because they a smaller than those you recommended, I had to modify lots of pieces to adapt to the project. Although the hardworking I have to confess I´m having progress and lots of fun.

    • Profile photo of Gael Langevin

      Bonjour Dany, You should post your questions on the forum, it would be better. (forum)
      Les pièces du torse et estomac sont emboitées. Suivant votre qualité d’impression, celles-ci tiendront bien ensemble ou peut-être pas, dans ce cas il vaut mieux faire des points de collage aux endroits qui vous paraissent stratégique. Pensez démontage car peut-être aurez vous envie d’installer des updates par la suite. Donc évitez de tout coller inutilement.

    • Profile photo of Gael Langevin

      Tutorial pictures for the shoulder are based on my first design. I have modified them over the years, but they remain pretty much the same. Unfortunately I didn’t re print my latest updates and therefore haven’t been able to update the tutorials. If you have doubts, you can always post your questions on the forum for help.

  4. Profile photo of Bernhard M

    Hi Gael,
    I am now printing parts for the shoulder assembly. I found schematic on the parts fit together. However from the list of parts, I am unable to locate a schematic assembly for the remainder of the parts:

    Is there an exploded diagram that shows the assembly for the remaining parts?

Leave a Reply