September 2, 2025
Description
Cat lovers, fans of programming, Arduino, 3D printing and assembly, this is the project for you!
Some will see this funfair wheel as a distant childhood memory that will transport them back to it. Others, though it may have been part of their childhood at another time, will see going to an amusement park as still relevant today! Finally, the last category will see in this project a way of miniaturizing the attraction for which they silently beg their parents.
WARNING - This version is a prototype and may not work properly. If you want a 100% functionable model please wait for the realease of the V.3.
My name is Elie, I'm 14-year old, I'm passionate about 3D printing, programming and robotics (and also about learning languages, climbing and playing the cello, but that's out of context), and I designed this concept from A to Z without any help from parents (and yes, there must be a 98% probability that the second question I'm asked after “What activities do you do?” is, “How do your parents get you to do all this? Or “Do you do it all with your parents?).
When I saw the theme of this competition, a few days after it came out but long before entries could be submitted, I thought I had to do something.
I immediately thought of a dispenser for my cat Merlin, which I'd wanted to make for a long time but hadn't taken the time to think about exactly what I was going to do. Now I knew I had to do something, and every day it became a topic where I spent a few dozen minutes brainstorming, looking for original concepts that would break away from the classic cat dispenser that a guest sees in your home, without actually seeing it. You had to find something that would make anyone coming to your home asking:
“- Wow! That looks extra cool, where did you get it?
- It's a dispenser I've made. I was looking for something original!”
After a few days, I had an idea - probably not during the time I'd set aside for brainstorming, certainly when I was falling asleep. The idea was for a Ferris wheel to distribute food.
The next day was Sunday (I remember because it's the only day of the week I can spend all day working on the same thing) and I worked on the concept all day. By the end of the day, I'd arrived at V1 of the dispenser. About a hundred pieces, with a goal of zero glue spots (I admit that in retrospect, it's a bit of an exaggeration, about 100 pieces, just to avoid using glue).
I remember being very happy with my day, and in fact it must be the first time I've finished V1 of such a project in one day! And the very next day, I started printing. After three days of delayed printing, I have all the parts. Once all the parts were printed, I must confess that I lost my Lego instinct a little and... the motivation to assemble, with difficulty (I realize), 20 parts for just the central wheel went down... to around a negative number.
The following weekend, I decided to start from scratch. So I'm starting afresh, still with the “zero glue spots” objective, but this time with the aim of limiting - a lot - the number of parts. I've recently learned how to make parametric designs, which allow you to change only one value somewhere and then change it everywhere, and it's a real joy, especially when you see how much time it saves on projects like this!
This time, after just one afternoon, I finished designing what will become V2 once I've made all the necessary corrections. We've gone from a hundred pieces to around twenty (I cut the wheel in two parts so I could print it in print-in-place with the stems in particular). I start printing - which I'm going to struggle to finish before the vacations, as I'm concentrating on my exams - and two weeks later, the vacations arrive and I can embark on what seems to me to be the last major iteration (you'll read later that there are still some very interesting improvements to be made). I start assembling it, and immediately realize that it looks nothing like the first version! There are still a number of modifications and adjustments to be made, but overall I'm very happy with this version once again!
Corrections and printing - including a few climbing sessions - will take me until 2am on Saturday (the time I finished my last print), and we'll be off on vacation 2 hours later. This is where I hope my last print (which lasts 5 hours) doesn't fail, because I won't have time to start another one. What's more, I also hope that all the decisive corrections I've made are correct, otherwise I won't be able to take part in the competition.
As I write this path to the published version for the contest, it's Monday, 10:45 a.m. and yesterday I did the assembly. I've managed to fix all the problems I'd found, so you'll know my entry in time for the contest.
Now, I'm not going to tell you that everything is perfect, and that I've managed to make the best entry, because there are still improvements to be made, which I'll do as soon as I have access to my computer where I do the 3D modeling for the smaller ones, and which I'll take the time to do progressively over time for the bigger ones. This project hasn't got yet the “finished” label, but rather the “improvements in progress” label.
So, here's a non-exhaustive list of the improvements I'd like to make:
With all these improvements, I'll consider V2 complete, and invite you to stay tuned for V3, which will include a water dispenser.
You will certainly have noticed that, unlike many food dispensers today, this one is not connected. This is a personnal choice, as I don't think an animal needs to change its feeding time every day. However, in a future version, I'm thinking of adding a button located in the tank or at a level that an animal wouldn't be able to reach, to dispense kibble when needed.
You need to print the number of parts specified in brackets in the file name (often 1 or 4). Don't hesitate to play with colors for the different parts of your dispenser! You do not need the files in the folder “Old versions”.
Here's the assembly video, with all the instructions inside!
As for assembly, all parts fit together. To assemble certain parts, you may need some 1.75mm filament to secure them (particularly for assembling a base leg). If some people don't have 1.75mm filament and only 3mm, don't hesitate to ask me in the comments to make the files for 3mm filament.
A PDF assembly guide will be soon available to help you get the food dispenser for your favorite pet as quickly as possible!
For the moment, I'm relying on a system that assumes that the basket is exactly under the tank for a precise period of wheel action.
To be more precise, I've timed the time it takes for the wheel to make one revolution and then, as I have 4 baskets, I've divided this time by 4. So, each time the motor is activated, the wheel makes a quarter turn before stopping. One drawback to this is that it doesn't take into account external interactions (if the wheel is blocked for a quarter of a second, for example, the basket will no longer be in the correct arrival position - we can also think of our dear cat who might have enjoyed playing with the wheel).
To solve this problem, I'm thinking of integrating an ultrasonic sensor to determine when the wheel is in the right position. If you have any clever ideas, I'd love to hear them! I'm also thinking of integrating a clock module in the next few weeks to allow for power cuts.
Finally, in the next version, I'd like to create an assembly that could run on a rechargeable battery - which could easily be clipped on and off to recharge it.
In the meantime, the code and schematic are available in the files!
You'll need just three components for this first version:
Thank you very much for reading the whole description, I hope it helped you understand the project and how I created it! Feel free to put a like and a comment to support my projects and the time spent doing the design and all the necessary corrections to get here!
Some additions and modifications:
I made a few modifications to the feet to reduce friction between the foot and the wheel.
License:
Creative Commons — Attribution — Noncommercial — Share Alike
Club Scientifique International
