Introduction: Otto Cardy a Cardboard Robot

About: Claudio Gasparini. I am involved in CAD, 3D Printing, STEAM, Coding and Robotics. I love developing Educational Robotics. My info:

Otto Cardy is an #OttoRemix entirely cardboard version of the original #OttoDIY of which he takes over all the electronic components and programming with OttoBlockly.

All information on how to build the OttoDIY robot with the 3D printer and all types of electronic components are available at and on the official website

This project shows specifically how to build Otto Cardy the #OttoRemix but made entirely of Cardboard.



(All the electronic components are the same as OttoDIY)

1 x Arduino Nano

1 x Nano Shield I/O

1 x cable USB-A to Mini-USB

1 x ultrasound sensor HC-SR04

4 x Micro servo MG90s

1 x Buzzer

24 x Female/Female Jumper Wire

10 × Female/Female Jumper Wires

1 x Nano Shield I/O

1x charger + power booster + 16340 Lithium Battery or 2x Battery CR123A or 16340 + Battery Holder CR123A

1 x Small Phillipis screwdriver

Specifically for Otto Cardy

2x Cardboard sheet A4 2mm, Corrugated or Greyboard

1x clip of Ikea Bevara Bag Sealing Clip

Step 1: Body Building

To begin with, you can start by cutting the body of the robot consisting of three pieces that must be wedged together. The two PDF files Otto_Cardy1.pdf and Otto_Cardy2.pdf contains the technical drawing of all components and must be printed in A4 format. To get the exact dimensions please print at 102% size.

The A4 drawing should be glued to the cardboard and then cut along the edges indicated by the continuous red line. It is recommended to use a sharp cutter for the holes and the openings. The dashed red line indicates where to fold the edges of the carton while the dashed lines of other colors indicate projection lines.

In image, points A are marked in red to facilitate the assembly of the pieces. To increase the rigidity of the structure where the motors are hooked, I used two overlappings pieces and glued layers of cardboard.

Step 2: How to Make Head of the Robot

The second drawing OttoDIY_Card2.pdf contains the quoted reliefs of the components of the head with all the closing pieces. The design of the legs and feet, being symmetrical, are drawn only once, and it should be remembered that they must be printed twice and must be glued in a mirrored way: in the drawing is inserted the inscription x2.

In yellow, the drawing of OttoDIY's head (HEAD) with its cover is highlighted. The part corresponding to the foot (FOOT) is dealt with in the following chapter.

To facilitate assembly, the points (A) that must coincide in the two pieces are highlighted in red color.

The two pieces must be assembled using glue and masking tape to hold the various parts during assembly. Start by matching the letter A with two pieces and then following the outline. You can put glue along the entire edge and place it in succession

The head must be inserted accurately outside the body and must therefore be "built" and closed using the body as a template and reference shape. To have a good closure between the two pieces, try to give the two a slightly conical shape in oerder to have a precise interlocking but also easy to remove

Step 3: How to Make Legs of the Robot

In the second drawing OttoDIY_Card2.pdf there are listed all reliefs of the legs and the feet. The design of the legs and feet, being symmetrical, is printed only once but must be made in two identical copies: in fact, the inscription x2 is inserted in the drawing

The legs are formed by cardboard wrapped around the motor and glued to the holder, which is screwed to the head motor.

The leg supports are made from a single clip, cut to a length of 25 cm. 

Example of the cut (red lines) of the Sealing clip:

  1. The two final parts cut to a length of 25 mm (SUPPORT ON FOOT in the drawing)
  2. Grooves where to insert the motor and the Servo Arm. The hole has a diameter of 8 mm
  3. Support mounted in the motor
  4. Servo Horn modified to "dovetail"
  5. Groove where to insert the Servo horn.

The two supports are the only components of Otto cardy that are not made of cardboard because they must be very sturdy as they must perform the structural function of supporting the legs.

Before gluing the leg, as in the following figure, it is necessary to calibrate the motor in the basic position.

With this operation, you have fixed the legs to the motors of the body, and as you can see from the photo, once the bands are fixed, there’s no more access to the screw that fixes the supports.

Therefore, it is essential to adjust the position 0 (zero) of the engines before closing the leg.

Step 4: How to Make Feet of the Robot

The foot is made of a cylindrical piece of cardboard connected to the engine by the Servo Horn and a screw as a pivot.

The use of cardboard to make the foot support is undoubtedly easier and faster: it is enough to find a cardboard tube of approximately 40 mm in diameter and cut it accordingly to the design scheme. I used the Kitchen paper towel tube, which had the right consistency to support the structure.

But in the final prototype, I used a cut and molded toilet paper tube to get a diameter of 40 mm. Then I covered it with coloured paper both outside and inside, for it to look better and to strengthen the feet.

List of components:

  1. Leg
  2. Servo arms shortened
  3. Cable outlet
  4. Pipe with fixing screws
  5. Shoe

Step 5: Assembly of Components

The final part of the assembling process involves the insertion of the expansion board and the various connections to the motors.

After making the cardboard components, we can proceed with the assembly: remember that on the site you can find all the information about assembling process even if the construction includes pieces made with the 3D printer.

There is no difference in electronic components between cardboard and 3D printed version.

In this image, all the electronic and cardboard components of the robot are represented according to their mounting sequence.

 The assembly scheme and electronic components do not differ in the two models made with the 3D printer or cardboard.

 The numbering of the diagram continues the mounting sequence of the cardboard robot from the head (HEAD) to the foot (FOOT) with the number #13

Step 6: Lesson Plan for the Teacher

Guided exercises to learn the how to use block coding

to control the movement and sounds of the OttoDIY robot

WS 1 Lesson plan for the teacher

1. Prepare

  • You can prepare same movement examples (sketch) chosen from OttoBlockly Examples.
  • Identify different task to assign to each group 

2. Engage (5 min.)

  • Get an overview of the movements and sounds provided by the program that you can add.
  • Present the function of the “dept sensor” and the distance it detects
  • Point out the pitch of the notes and the length of the sound.

3. Explore (15 min.)

  • Invite students to work in pairs or groups 
  • Invite to elaborate a work strategy using the sound-movement-dance-distance functions.

4. Elaborate (20 min.)

  • Invite students to program movements using sounds and gestures.
  • Ask them to insert musical sequences that their like between the movements of the robot.

5. Evaluate

  • Create an evaluation form for the work of individual students taking a cue from the evaluation provided.