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My previous instructable was an attempt to make an eye mechanism that was as accessible as possible to as many people as possible, but in this project I wanted to design something that was more of a middle-ground between accessibility and quality. This design features some more speciality parts such as servo ball-links and pushrods but it’s still quite easy to build. It uses a mechanism design which is commonly used in professional eye mechanisms, but it circumvents any machining by using parts that are designed for 3D printing. Compared to my previous design, it is much more compact, robust, and a little lighter.

Another feature of this design is that it’s designed to use snap-in eyes which can be replaced, and used with other 3d printed components to cast a highly realistic dome over the painted eye. This process is quite involved so I have another instructable on how to make the eyes, but if you’d prefer to use simple 3d printed eyes you can do that too.

The requirements aren’t too high, but I’d recommend that you be fairly comfortable with 3D printing before attempting this project - you will need a printer that can reliably print at 0.15mm - 0.2mm layer height, and it’ll need to be calibrated well enough to print small parts to be quite strong, which also entails using decent-quality filament. If you’re using something like an ultimaker or makerbot you should have no trouble at all, but for folks like me using cheaper 3D printers you may need to go through a bit of trial and error to get your print settings perfect. If you’re looking for something easier, have a look at my previous instructable.

Also, making the eyes was a tricky process and not necessarily needed to make this project, so check my other instructable for how to make the eyes.

Screws: (this kit should cover you)
Around 40M2 x 6mm screws_
10mm M2 screws

6 MG90s servo screws (these come with the servos:
_Hobby Components

M2 Servo Ball-links:

4* M2 x 25mm Pushrod Connectors: (keep in mind this is just 2mm threaded bar - you could always cut down a 25mm bolt or some plain threaded rod)

Arduino Uno: (or anything that can accept three analogue signals, one digital and communicate through SDA/SCL ports)
Adafruit PCA9685 16-Channel Servo Driver:
5V Power Supply, around 4A is more than enough. Here is mine (

A female DC power jack to match your power supply, to be soldered to the servo driver board

2-axis Joystick:
Potentiometer (optional):
Push-to-make switch (Some joysticks have this built in, but its easier to control when its

10k Resistor:
Jumper cables:
6* MG90s servos:
Also, a pin vice hand drill might be useful for adjusting hole sizes:”

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