DIY Robot Kit – Otto

Otto is an interactive robot that anyone can make!, is completely and truly Open source, Arduino compatible, 3D printable the perfect opportunity to build and have your very first robot, learn robotics and have fun; is more than just a robot a truly emotional robot that connects with all people, allowing everyone to interact socially.

Otto’s differences are in the assembled size (11cm x 7cm x12cm), cleaner integration of components and expressions. Using off the shelf and 3D printed parts, simple electronics connections (almost no welding required), and basic coding skills, you will be able to build your own cute Otto friend in as little as two hours!

Step 1: First gather all parts and tools

Gather all the off the shelf hardware parts that you’ll need for this assembly.

A mini breadboard is an alternative for the shield but more wiring and time required

Optional: cutter for post cleaning the 3d parts (if the 3d print quality is good enough no need) and a soldering iron (if you want it battery power otherwise can still connect it through usb to energize)

That’s all simple!; Download all .stl files, If you do not have a 3d printer you can always use services like or local maker spaces.

The total cost of this materials should be no more than $49 US

Step 2: 3D Printing

Otto is very well designed for 3D printing, the files that you had downloaded are property oriented and centered, so wont give you trouble if you follow this common parameters:

  • Recommend using a FDM 3D printer with PLA material.
  • No need supports or rafts at all.
  • Resolution: 0.15mm
  • Fill density 20%

For slicing and generating the g code for the machine free slicer software like Cura or in our case FlashPrint that comes with the FlashForge Finder 3D printer that we are using (If you are outsourcing the printing no need to worry about it)

After printing you will need to clean a little bit the legs and feet areas that fix the motors.

From the 3D printer that makes Ottos, to some moves that Otto can make in his 2 legs.

Step 3: Reorganize & check your parts from bottom to top.

As mention in step 2, Micro servo motors come with 3 screws in the picture are now included and rearranged the parts number for easy reading.

Remember to have magnetized your mini screwdriver.

Step 4: Foot servos assembly

Put the micro servo inside feet and then push it inside, if is to hard maybe need to clean more the area with a cutter.

Is very important to check that the servo is able to rotate at least 90 degrees to each side.

After checking the movement use only the small screw to fix it.

Same process for the other foot.

Step 5: Fix Servos to Body

Take the other 2 micro servos put them in the defined locations in the 3D printed body and fix them only with the pointed screws.

Step 6: Fix Legs to Body

Connect the legs to the hub of the micro servo, important like the foot servos you must check the legs are able to rotate 90 degrees each side respect to the body.

After verifying the alignment fix them using the small screws to the hole inside the leg.

Step 7: Fix Foot to Legs

Taking care of the cables as showed in the illustration you should put the cables inside the slots of the body passing thought the hole of the legs.

Once they are in right position use the pointed screws to fix them from the back.

Step 8: Head assembly

Start from the ultrasound sensor is important to pull out the eyes to the limit.

After putting the Arduino nano in the shield, optionally you can weld the battery holder positive cable to Vin in the board and negative to any GND.

Insert diagonally the both boards together facing the USB conector to the hole in the 3D printed head, then use the last 2 pointed screws to fix it.

Step 9: Electric connection

Prepare the breadboard cables and buzzer.

Then follow the diagram pins numbers and make sure to put them in the right position.

If you don’t have or find the Arduino Nano shield use a breadboard and follow this circuit diagram Autodesk Circuits

Step 10: Snap the head and upload the code

The Head have 4 snap, take care of the cables and snap it.

For the coding part you will need to:

  • Copy Oscillator libraries to C:\Users\user\Documents\Arduino\libraries (or wherever your library folder is installed):
  • Connect your Otto through USB (your computer should install the drivers)
  • Finally open & upload OTTO_smooth_criminal.ino code to your Arduino Nano and Otto ready to dance!

You can always try different codes from the Github repository.

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