Fat Pet Feeder

What is it? Fat Pet Feeder is a first fully featured 3D printed pet feeder you can put in your kitchen and not being ashamed of it. Because it looks, works and feels awesome.

Main reasons to try it:

1. Keeps your pet diet healthy, limits daily calories if needed;
2. Feeds your pet while you're away
3. Keeps the food fresh, cats like it
4. It's a great building kit for kids, adults, schools and robotics courses. It's meaningful and satisfying.

Arduino sketch wall socket version with timer

Arduino sketch battery version with button

The code is provided as is, I can't write the code for your specific requirements but I can help you with debugging specific issues if any appear.

Features

• Designed to be 3D printed easily without supports.
• Modular and upgradeable – if a part breaks or needs an upgrade you can easily replace it.
• Easy to assemble. My 6 year old son did it twice. Parts just fit together and are fixated with 4 M4 screws.
• Battery compartment – you can use a single set of 3 D-size batteries to power it for more than a year. You don't have to use it but it's there. The feeder also has a standard power adapter mount hole.
• Parametric model – you can play with the parameters to make it fit your specific requirements (for different bowl sizes, pet sizes, internal volumes etc). This distribution includes the default 1L version. Source files are given so you can make a larger version. Fusion sometimes breaks the model when parameters are changed so probably I'll have to include larger version STLs into the distribution if there will be enough requests for it.
• Standard size motor, power socket, micro switches
• 1L food container in the default version and can probably go up to 5L or even 10L if you make it tall enough
• 3 programmable buttons – set portion size and schedule
• Free software
• Precise serving size
• Programmable, customisable. Do you want it to have an internal camera with a raspberry pi PC inside? A walkie-talkie? A display with a counter? Wi-Fi, IFTTT and smartphone controls? Anything is possible.

How to print

Fat Pet Feeder consists of 8 printed parts. It's easy to print if you use decent quality PLA filament – 45 degree overhangs and good 30mm bridges are a must. ESUN PLA ($20) – good enough, FDPlast PLA ($10) – not good enough but I still managed to use it (orange+white on the photos). You will need ~0.7kg of filament. Use 2+ colors to make it stand out. You can use color print to change your filament at the right height.

It is not print-in-place, parts are printed separately. I used 3 perimeters with 20% infill, 6 bottom and 8 top solid layers, default speed (I used 100 perimeter speed on some feeders, grey on photos).

I recommend printing parts in this order to be sure that everything fits together and is printed well before it's too late:

1. Hopper
2. Portion wheel
3. Wheel compartment
4. Electronics compartment
5. Bowl
6. Shell – I recommend adding brim. It could warp otherwise. Yes, even PLA.
7. Lid
8. Battery cover (optional)

Parts required

1. SpringRC SM-S4303R Continuous Rotation Servo or similar
2. Arduino – you can use any version, I recommend nano because it's small and doesn't require separate USB interface module
3. 3 micro switches (optional)
4. Breadboard/PCB, jumper wires
5. 4 M4 countersunk screws. Any length, I used 10mm.
6. 5V 3A power supply
7. DC power jack female connector
8. Stainless steel bowl, ~0.5-1.5 cup in volume for default version, 30-50mm height (optional)

Affiliate links for all the parts are in the video description: https://www.youtube.com/watch?v=sCOkuyH7CPo

For a battery powered version

There's no special 3D model for that, you can modify your feeder for battery power at any moment. It's a bit more complex than just to print, upload sketch and put together. You have to know how to change bootloader, microcontroller fuses and maybe some more electronics knowledge.

1. Atmega 328p or similar. You can still use any arduino but you have to break some parts of it to make it power efficient. I used the same arduino nano. If you use standalone microcontroller then you may need capacitors and a resonator but these are optional if you use a programmer and internal resonator.
2. MOSFET with low gate threshold. I recommend IRL540N
3. 5V 2-5A boost converter. I recommend LM2587 or similar module
4. Optional decoupling capacitors. I used 1uF electrolytic and 0.1uF ceramic
5. 3 D-sized batteries
6. Another arduino or a programmer to change a bootloader or use sketches without one

Q&A

Do you include source files?

Yes, there are F3D Fusion 360 sources. Fusion 360 is free for personal use. If you need any other format like OBJ or STEP, let me know.

Is it reliable enough?

Yes, it's tested for months with 3 cats. No jams because of the wheel design and software fallbacks. It's durable. Theoretically some pets could break it open but it would be a very rare exception.

Will my pet like it?

If you feed it primarily with dry food, there's very little difference introduced.

Is it safe?

Yes, but you have to use good PLA filament, maybe natural color for the funnel part is better. You can use PETG/PA/PC but I don't see any reason for that considering the price. Also to prevent acne on the chin of your pet I recommend using it with a stainless steel bowl.

Do I have to buy a new bowl?

No if you have one that fits or if you're ok with the printed one. There are several bowl holders in the package so you can use the one that matches your bowl. The joint is universal for all of them so you don't have to reprint everything.

Do I get hardware and software updates for free?

Yes.

Do I need to have 0.05mm tolerances on my 3D printer?

No, any modern 3D printer with 0.4mm nozzle and 0.2mm tolerances is good enough. You can use files or sanding paper if something sticks out.

Do I have to know how to write code or solder?

You don't have to because there are jumper wires, breadboards and free ready to use software. But this project could be a good starting point for you to dive in. Everything is provided AS IS so if you have special requirements you should be able to implement them.

How much will it cost to make the entire thing?

$15 filament + $2 arduino clone + $3 breadboard, wires, connectors, micro switches + $3 power supply + $8 servo = $31.

To make it battery-powered it will cost you $10 with batteries.

What are the printing dimensions of the printer required?

210mm (l) x 150mm (w) x 210mm (h)