Introduction: Eggduino - Eggbot - SphereBot - the Machine for Drawing on Eggs

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About: I create projects for my videos that I publish on my YouTube channel

Welcome to this tutorial! With Easter approaching, I will show you how to build an Eduino, a small robotic arm that, thanks to Arduino and Inkscape, can draw on eggs to customize them however you like.

I had to condense many of the construction steps, otherwise this Instructable would have become too long. If anything is unclear, you can watch the video.

Supplies

Bill of materials and purchase links:

Nema 17 Motors:https://s.click.aliexpress.com/e/_DkfI5Dx

CNC Shield V3 + A4988 Driver:https://s.click.aliexpress.com/e/_opux3l7

Arduino UNO R3:https://s.click.aliexpress.com/e/_omrkKfL

12V 30x30 Fan:https://s.click.aliexpress.com/e/_DBctEoN

Jumpers:https://s.click.aliexpress.com/e/_DlW0APb

Steel Rod, 4mm Diameter, L = 68mm:https://s.click.aliexpress.com/e/_DdGbfvF

Compression Spring 20x9:https://s.click.aliexpress.com/e/_DCgg7op

50V 10µF Capacitor:https://s.click.aliexpress.com/e/_DBg9N6V

9g Servo Motor:https://s.click.aliexpress.com/e/_oBuQg77

12V 5A Power Supply:https://s.click.aliexpress.com/e/_DFEvwEh

DC Connector 5.5x2.1mm 12V:https://s.click.aliexpress.com/e/_DENlicH

Bearings 4x12x4 604ZZ:https://s.click.aliexpress.com/e/_DmvNMA1

Hex Socket Head Screws M3:https://s.click.aliexpress.com/e/_DeWHGzn

Flat Head Screws M3:https://s.click.aliexpress.com/e/_Dk9vcwv

Countersunk Head Screws M3x8:https://s.click.aliexpress.com/e/_DeN8z2z

M3 Nuts:https://s.click.aliexpress.com/e/_DFW6nJR

Sharpie Permanent Markers:https://s.click.aliexpress.com/e/_DDyxiw1

Plastic Eggs:https://s.click.aliexpress.com/e/_DkIaUKh

Various Silicone Wires:https://s.click.aliexpress.com/e/_DE04sfL

----> 3D parts to print:Makerworld <----

----> Documentation <----

Step 1: Motor Assembly

Installing the Egg-Driving Motor

To install this motor, we will use M3x10 screws with 3D-printed spacers to fit them.


Step 2: Assembling the Marker Holder Arm

This motor will be mounted on the lower side using M3x10 screws and spacers, while on the upper side, we will use M3x5 hex socket head screws, recessed into the frame to avoid interference.

Step 3: Servo Installation

We use a 9g servo. To connect it:

  1. Modify the connector: Separate the signal wire (orange) and use a single pin, while the positive and negative wires go into a dual connector.
  2. Position the servo: Route the wire through the groove to prevent it from interfering with the arm.
  3. Secure it with the provided screws.


Step 4: Uploading the Sketch to Arduino

Download the Eggduino.zip file, extract it, and open eggduino.ino using the Arduino IDE. Install the necessary libraries:

  1. AccelStepper (available in the library manager)
  2. SerialCommand (manually installed via ZIP)

Connect Arduino to the PC, select Arduino Uno as the board, and upload the sketch.

Step 5: Assembling the CNC Shield and Drivers

  1. Install the CNC Shield V3 onto the Arduino Uno, ensuring the pins are properly aligned.
  2. Mount the A4988 drivers in the X and Y slots, with the potentiometer facing the power supply.
  3. Configure microstepping using jumpers to achieve 1/16 step resolution.

Step 6: Adjusting the Drivers' Vref

We calculate the Vref based on the motor’s maximum current (from the datasheet) and adjust the potentiometer using a multimeter:

  1. Connect the multimeter's negative probe to GND
  2. Place the positive probe on the potentiometer screw
  3. Adjust until reaching the calculated value

Vref calculation site

Step 7: Power Supply and Final Adjustments

  1. Enable the board by placing a jumper between EN and GND.
  2. Disable auto-reset by soldering a 10μF capacitor between GND and RESET.
  3. Connect the fan to the CNC Shield for cooling.
  4. Secure the power socket and connect the cables.
  5. Connect the motors:
  6. Arm motor → driver Y
  7. Egg motor → driver X
  8. Install the bearings and egg rollers, using rubber to increase friction.
  9. Place the electronics cover and apply the custom logo.

Attachments

Step 8: Testing With Inkscape

Open Inkscape 0.91 (See documentation) and follow these steps:

  1. Modify the document size to 3200x900 px.
  2. Paste the design you want to print.
  3. Go to Extensions → Eggbot → Eggbot Control.
  4. Set the pen height values (e.g., 55 and 70 for up/down).
  5. Run a test print to check if everything is working correctly.

After the test, you can proceed with the final print!

Step 9: Multicolor Printing Setup