Will Cogleys Eyemech

Hey robot makers,

This week, I’ve been diving into one of the most exciting projects I’ve worked on in recent times—animatronic eyes that I’ve 3D printed to life.

Discovering Will Coley’s Eye Mechanism

This fascinating journey began with Will Coley’s Animation Eye Mechanism, the Epsilon 3.2 series. Will, a talented engineer based in London and owner of NM Robotics, has honed this design over several years. He not only sells the controller boards and ultra-realistic eyeballs but also provides the design as open source. You can download the STL files for free from Printables or MakerWorld.

The mechanism operates with six SG90 (or MG90) micro servos per eye pair, giving it comprehensive motion including up, down, left, right, and eyelid control. Will has also developed a dedicated controller board, based on a Raspberry Pi Pico, which I’m currently using. Running on Will’s MicroPython script, it’s mesmerising how naturally the eyes move around.

Building the Eye Mechanism

When building my version, I ordered a box of ten SG90 servos from Amazon. The servos fit well with the SG90 A model files available on the Google Drive links found on Will’s designs page.

The initial challenge was navigating the 3D printing process with PrusaSlicer and ensuring that the components printed correctly. This was especially tricky since the print in place parts needed precise alignment. My first attempts revealed misaligned and fused parts, especially when opening files designed for Bambu Studio within PrusaSlicer. Thankfully, using the EasyPrint option from Printables helped rectify the alignment issues, resulting in successful prints.

Wiring and Setup

Once I had all the parts in hand, I wired them using a Raspberry Pi Pico with guidance from Will’s diagram (which is included in the project Zip file). This setup included connecting the GPIO pins, ensuring 5-volt power from the USB pin, and grounding as specified. I used a custom helper circuit — a servo helper I designed—to make the servo connections simpler and more efficient.

With everything wired and the MicroPython code ready, it was time for calibration. This process involves setting the servos to a neutral 90-degree position, following instructions provided in the build PDF to ensure proper alignment of the eyelids and eye positioning.

A History with Animatronic Eyes

This isn’t my first foray into the world of animatronic eyes. I’ve worked on several projects, including building an InMoov robot named Sonny. This project presented its own set of challenges with eye and jaw mechanisms occasionally catching.

Another significant project included designing an eye mechanism from scratch inspired by Will’s designs, using Fusion 360. This model incorporated upper and lower eyelid movement, a Raspberry Pi camera embedded in the right eye, and was enhanced with a NeoPixel ring for added flair. Named “Bubo” this creation took inspiration from the steampunk-themed robot owl in the film Clash of the Titans (1981).

Future Aspirations

Looking ahead, I’m inspired to refine these animatronic eyes even further. Imagine a head that can track individuals, engaging in or avoiding eye contact based on its programming. Leveraging the Raspberry Pi 5 capabilities, there’s potential for endless creativity in interaction possibilities.

I hope you found this exploration as fascinating as I did. Stay tuned for more adventures in the realm of robotics!

See you next time. Bye for now.

Links

• Will Cogley / NMRobotics: https://nmrobots.com
• Eye Mechanism STL files: https://www.printables.com/model/1220172-animatronic-eye-mechanism-e31
• Will’s YouTube: https://www.youtube.com/@WillCogley
• My Bubo video: https://www.youtube.com/watch?v=-H8prWRdSAI
• Bubo build