Applications & implications

This week I did some more detailed design and planning for my final project. I considered the turntable belt mechanism that moves the feeding structure, as well as just the feed screw, and the wiring of everything and how it should look.

Questions to be answered:

What will it do?

For my final project, I decided to make an automatic modular cat feeder. This will facilitate the feeding of my cats when I am not at home, and also help me to control the amount of food they each eat. It is comprised of two main systems: the feeding mechanism and the access control system. The feeding mechanism is responsible for dispensing a specified amount of food to specific cats. The access control system is responsible for controlling the access of each cat to the food, by reading the RFID tag of each cat.

Who has done what beforehand?

There are many automatic cat feeders on the market, and also many cat doors that use RFID tags to control access. However, I have not found any that combine both systems, maybe because it is not a common need. Regarding the door system, my main inspiration and where I drew a lot of ideas from was Pamela Arana's final project. As for the feeding mechanism, I was first inspired by Toni F. Barreiros's final project, because of the specific screw mechanism he used. Later with more research, I also found more projects with the same idea but with other features like an interface to control the amount of food dispensed, like these projects: DIY Pet Feeder based on ESP8266, this instructable Pet Feeder Controlled Via WiFi, and this automatic fish feeder.

What will you design?

I have designed the whole feeding mechanism. This includes all of the 3D printed parts, the PCBs, the whole mechanism, and how everything comes together and connects. This, of course, excludes the parts I bought (PVC tubes, turntable bearings, screws, nuts, bolts, etc). Regarding the access control system, I used Pamela's project as a base and made some modifications to fit my needs. The cat gate design is very similar to hers with modifications to fit my needs. The house structure for now is also her design that I redesigned to be able to cut with MDF and allow the feeder to be integrated into it. I did this for now because of time constraints, but I plan to make a different house design when I get back to Portugal, since currently this house design does not allow much room for more cats to be added to the system.

What materials and components will be used?

• Materials and components:

  I made a more specific list of components and materials that I will use in my Bill of materials.

  • MDF for the cat house and box to house the electronics
  • Acrylic for the cat door
  • PETG for all of the 3D printed parts
  • PVC tubing for the feed screw enclosure
  • RFID tags for the cats
  • RFID reader
  • Servo motor
  • Stepper motors
  • Motor drivers
  • PCBs
  • Real cats for real testing

Where will they come from?

The materials and components will be bought from local stores or online, made in the fablab, and also already available in the lab.

How much will they cost?

See the bill of materials here: Bill of materials.

What parts and systems will be made?

I will try to make as many parts as possible, however, some parts make more sense to buy, like the PVC tubes, since these are cheap to buy and readily available. This will make my project easier and cheaper to recreate.

What processes will be used?

3D printing, laser cutting, CNC milling, PCB milling, soldering, programming, and a lot of testing.

What questions need to be answered?

• Are my cats smart enough to use the system?
• How easily can I add more modules to the system?
• Will the interface work?
• Will my cats actually maintain a healthy weight and diet with this?
• How can I improve the RFID range?