A Proposal by Sterling Peet
Problem Statement
I have a cat that is terrible at using the litter box. I have a taken measures including using a litter box with a top and purchasing quality, scented, clumping kitty litter to help combat the issues, but the current situation is not sufficient. My cat does not understand the concept of burying her business, and thus my closet routinely smells like a small animal graveyard. Due to the configuration of my closet, bedroom, and other living arrangements, this aroma saturates my bedroom, and this is unacceptable.
A secondary complaint about my cat concerns her weight. That is, she has too much of it. She is fat. The solution for this is to feed her a measured amount of food, rather than just topping off the bowl all the time. Unfortunately, this also means she will wake me up in the morning to be fed, and I need to be available to feed her on a regular schedule. This is not compatible with my school schedule, so I want to build an automatic dispenser that can feed her the allotted amounts at appropriate times.
Project Requirements
The Primary goal is to exhaust the egregious odor out of the window in my closet [no, I don’t know why my closet has a window, but it makes a convenient place to pierce the brick wall for ventilation].
The opened window also needs to be discreet from the inside, the opening must be [mostly] only exhausting air, and located behind some piece of furniture to obscure and otherwise plug the opening.
The cat does not like having a gale force breeze blowing between her legs while using the litter box, so the exhaust fan must be controllable, preferably variable speed, and be able to sense the cat’s presence.
Secondary requirements include being able to feed the cat without needing human intervention on school days, a water dish with an overflow tray and catch bottle (she is a messy drinker), a remote administration and monitoring interface, and a place for the cat to play or look out the window. Additionally, the closet has ethernet, but not 110 AC.
Design Solution
To solve the primary problem and satisfy the design requirements, I plan to build a wooden cat tree to house the litter box, automated feeding bowl and water dish, cover the opening in the window, and contain a fan loaded exhaust duct. The duct will have a louver that closes when the fan is not blowing, in order to keep out critters and weather when not in use. The cat feeder and fan blower will be arduino based custom embedded circuits, and to provide reliable and maintenance free power and communication, the project will use a simple ethernet communication protocol and power over ethernet for the power supply. The fan circuit will employ an IR motion detector similar to those used for automatic doors to detect the cat entering and exiting the litter box.
Skills Summary
All of the skills required for this project are either skills in which I am already proficient, or I know that I am within reasonable reach of obtaining. The planning will require a drafting skills in Autodesk Inventor for the mechanical and EagleCAD schematic capture and board layout skills for electrical aspects. I have already proto-typed an arduino circuit that checks an IR motion sensor and appropriately controls a computer case style fan. The power over ethernet aspect is something that I wish to learn about, but I have a contact in the GT GVU that has down POE design, and I have already convinced him to teach me about it. The final aspect of this project requires programming skills, making this a particularly cross-discipline project.
Project Completion
This project is one that I feel is within reach of completing by the end of the semester. The most unlikely parts to complete are the final electronic assembly and programming, but the design of the electronics would be complete; with parts and circuit boards on order. The plan will be to start with the mechanical design of the cat tree to accommodate the litter box, exhaust duct, window opening, external vent louvers, and physical interface for the cat feeder and water bowl. Next the final fan control electronics will be developed, followed by the POE and ethernet communication interface. Finally, the feeder and water bowl will be developed along with the associated electronics. The only portion that I feel is questionable to complete by the conclusion of the semester is feeder and water bowl electronics, and again, this would be a result of waiting on circuit boards and parts to arrive.
Bill Of Materials
| Item | Unit Cost | Qty | extended |
|---|---|---|---|
| 2x2x4′ | $3 | 6 | $18 |
| 3/8″ Plywood | $20 | 1 | $20 |
| Fans | $10 | 2 | $20 |
| Custom Fan Control Circuit | $40 | 1 | $40 |
| Arduino | $35 | 2 | $70 |
| Custom Power Over Ethernet Circuit | $50 | 1 | $50 |
| IR Motion Sensor | $10 | 1 | $10 |
| Custom Cat Feeder Circuit | $40 | 1 | $40 |
| Cat Feeder NEMA17 Stepper Motor | $20 | 1 | $20 |
| Total | $288 |