Halloween Pumpkin With a Moving Animatronic Eye | This Pumpkin Can Roll Its Eye!
Introduction: Halloween Pumpkin With a Moving Animatronic Eye | This Pumpkin Can Roll Its Eye!
In this Instructable, you will learn how to make a Halloween pumpkin that terrifies everyone when its eye moves.
Adjust the ultrasonic sensor's trigger distance to the right value (step 9), and your pumpkin will petrify anyone who dares to take candy from your house!
In the above video, you will see a demonstration of the movements that this eye is capable of. The first 2 clips show the random twitchy movements that the eye can be programmed to do, and the 3rd and 4th clips show how the pumpkin can roll its eye in the same way that a human might when annoyed.
This was a Halloween rush-project for me, so I took most of the pictures after my project was done. This was also why rather than buying a universal joint for the eye, I designed a joint that doesn't require any hard-to-source non-3D printable parts. This is why you can complete this project in just one day!
Follow this link to the accompanying file repository, or, copy and paste it into your browser https://github.com/roy-rishi/Animatronic-Eye-Halloween-Pumpkin
Supplies
1. 1x Arduino Nano (or similar)
2. 2x SG90 9G Micro Servo
3. 1x Pumpkin (at least ~20cm in diameter)
4. 2x Wood Skewers
5. 4x AA Batteries (or a similar 5V setup)
6. ~Jumper Wires (or 1m of 22 AWG Wire)
7. ~15cm Bend-and-Stay Wire (paper clips work fine)
8. A Few Markers or Paint (red, blue, and black colors)
9. 769
White Filament
Optional:
1. 1x HC-SR04 Ultrasonic Distance Sensor
2. Soldering Iron and Solder
3. Electrical Tape
Step 1: 3D Print the Files for the Eye Mechanism
First, you will need to 3D print the attached STL files in white.
Clone the GitHub repository. The folder contains all of the 3D and code files, as well as links.
The 3D files are already oriented in the direction that best suits 3D printing. It is important to note that "Outer-Eye" will need to be printed with the round side down, and "Inner-Eye" with the flat side down. Although this means you will need supports for the Outer Eye, you should not print either of these files in the opposite orientation. This is because the inside of the Outer Eye and the outside of the Inner Eye needs to be as smooth as possible to prevent the eye mechanism from binding.
I printed the Outer and Inner Eye parts at a 0.1mm layer height because that would reduce the stairsteps effect, thus resulting in a smoother surface. I printed the other files at a 0.2-0.3mm layer height.
When the project was ready to be displayed, I placed a flashlight directly behind the eye mechanism so that the eye would glow. If you want to achieve this glowing effect, I would recommend using low infill and perimeter settings for the Outer and Inner Eye parts.
Step 2: Basic Post Processing for the 3D Printed Parts
The only part that needs work is the Outer Eye.
Because supports were used on the visible side of the Outer Eye, the surface will be a little rough. Using ~120 – 240 grit sandpaper, smooth out the surface until it looks good (I know no one likes sanding, so just smooth it out until you are happy with the look, or completely skip this step).
Step 3: Make the Eyeball More Realistic
After sanding the eyeball to a relatively smooth finish, I used red, black, and blue permanent markers of varying widths to add an iris and blood vessels to the eye. (You can tell that I am no artist and that this instructable is not going to cover how to make a hyper-realistic eye).
I imagine you could make a hyper-realistic eye by priming and painting the eye, but I didn't bother with any of that; No one will see those finer details when your pumpkin is placed in the dark!
Step 4: Form the Linkages
Now that you have all of the 3D printed parts ready, you are almost ready to assemble the mechanism. You just need to bend 3 pieces of bend-and-stay wire (I used a standard paperclip) to form the linkages.
Using needlenose pliers, bend the wires until they have the same dimensions as the above picture. 116