My love for engineering and interactive design has always been heavily influenced by Disney. In particular, the Imagineers that fuel the invisible magic behind Disney parks through science and technology. When I was younger, Disney’s stories, characters, and unbelievable environments fascinated me, and as I grew up I was even more amazed by the idea that engineering made this magic exist in our reality. I recently had the pleasure of visiting the parks with a fellow engineering friend, and as college students in our 20’s, we had the most fun running around the park debating how everything worked.
At the end of the day, I wanted to discover a way to bring a bit of Imagineering magic home with me, so I started ideating ideas that combined my two favorite things – Disney and cooking.
The many ideas eventually evolved into a Wall-E themed toaster oven where the compartment in his torso would open up to be a mini toaster oven, capable of toasting a single piece of bread. The idea jumped out at me because it was something plausible that also aligned with the personality of Wall-E himself. Wall-E’s incredibly genuine and innocent nature makes him the perfect robot to have a wildly inefficient function, but be so happy about the final product. I loved the idea of a Wall-E that was so excited by the prospect of giving you a single piece of toast that he danced around with joy when the timer dung.
After ideation and sketching, I used Fusion 360 to create a 3D model of the Wall-E toaster oven. Although there are many 3D models of Wall-E on the internet, it was important to me that I modeled each piece myself referencing the designs used in the movie. I modeled each part individually and then combined them in one file to create the full model of the Wall-E.
The inside of the body was left empty, and using the dimensions of a mini Dash toaster oven, I created a “casing” to go around the oven. The body of the Wall-E is comprised of six different sides, all with specific engravings and openings for wiring and electronic fittings. Additionally, the body contains spaces for the arms, neck, and wheels, to be press fit in and glued onto.
The most challenging part of this process was creating functional wheels and treads to attach to the the body. I went through many iterations of the wheels to achieve a functional and aesthetically pleasing design. Overall, each wheel was composed of six different parts designed to fit together and allow for rotational movement of the two bottom wheels about one axis. The parts were specially designed to fit within the constraints of a 5″ x 5″ 3D printer, which was the accessible tool at the time of building. The wheels were held together using custom designed tread pieces that link together using dowels and were compatible with the curvature of the back wheel.
After 3D modeling was complete, I began to produce the parts. The majority of the parts were 3D printed including the arms, head, and the entirety of the wheels. The body, however, was CNC milled out of MDF. As mentioned before, each part was designed with the constraint of fitting within a 5″ x 5″ x 5″ volume due to the capabilities of our home 3D printer.
The other piece of machinery primarily used in the manufacturing process was a CNC milling machine. Due to COVID-19 conditions, however, most maker labs in the area were closed to the public, so I took the opportunity to build a DIY CNC machine at home using pipe and more 3D printed parts. The CNC was completed by following a tutorial from v1engineering.com/lowrider-cnc/. The sketches of each side of the box were exported from fusion 360 as a DXF file and cut on the CNC mill using a Dremel tool as the head. The 3D printed parts were exported individually as STL files and sent to the 3D printer. Each side of the box took approximately 3 hours to cut out and engrave while the 3D printed parts ranged from 3 to 48 hours to complete.
After all the parts had been printed, the supports had to be removed from each individual part and then assembled. As mentioned before, the wheels were comprised of six different parts that all attached together with press fits. The arms were made of three different parts that combined to attach to the hands which were comprised of three finger pieces and a dowel to allow for finger and wrist movement. Lastly, the neck and head were each made of two mirrored parts that were combined with gorilla glue after printing.
Once all the parts had been produced, I painted each one by hand using acrylic paint. I worked closely off of Wall-E reference photos in an attempt to achieve the same beat-up and rusted appearance that metal would have. The parts were then sealed with a paint finisher to protect against scratches in the future.
I believe that the electrical integration was the most challenging and informative part of this project. This is mostly because I do not have the same background in electronics as I do with mechanical engineering and design. The challenge was integrating the Arduino, both servos, LED light, fan, 5 volt transformer, and the toaster oven into the same power cord. Additionally, the Arduino needed to control the servo movement only after the toaster was finished toasting. To the left is a diagram that details how each component was wired together.
The knob on the toaster oven served as a switch that completed the power circuit when the knob was turned. This turned on the light, fan, toaster oven, and 5 V transformer. An Arduino Nano read the voltage going through the 5 V transformer and sent a signal to the servos when the voltage dropped from 5 V to 0 V, indicating that the toaster oven had finished.
Ultimately, all the wiring was done with the 3D parts disconnected and then tested. Before assembling the whole thing, I trimmed the wires, and used a combination of clamps and 3D printed parts to organize everything inside the body against the walls. The walls were then lined with carbon fiber to help protect the MDF, electronics, and 3D parts from the heat of the toaster oven.