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[on:]

Id love to build an automated pet feeder for my cat.

Not because Im lazy (ok maybe just a bit), but there are times when Im going away for just 24 hours, and its a bit of a hassle driving 10 miles to the cattery each time.

What Im thinking is some 10 inch pvc tubing filled with tasty biccies, with some sort of servo at the bottom, and an arduino controlling timing. Every 5 hours it rotates the servo, allowing a payload of deliciousness to drop into the bowl below.

For water, its less of an issue really, since my cat isnt going to drink a full bowl of water in 24 hours. But it would be cool to do water too. Maybe a similar sort of setup with a water float gauge to allow the bowl to remain filled.

Not looking for exact instructions on how to do this, just wondering if anyone has built something similar, or has other ideas on how best to do it?

Thanks

[Reply #1 on:]

For water, go with one of the dispensers where you fill a bottle & turn it over into bowl. Typically meant for dogs. We have 6 cats, this works for them.
http://www.newwaveenviro.com/selfrefilling-pet-watering-bowl-p-80.html
This size is overkill, but this idea anyway.
Purina used to have the same thing for cat food, little wedge at the bottom that let more food slide down as the tray was eaten from.  Still available it seems.
http://www.amazon.com/Petmate-Automatic-Feeder-Dispenser-Speckled/dp/B0027R273M

[Reply #2 on:]

I've got some advice based on my first attempt.  Here's my first design:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1282104243/0#0

The problems were: 
It dispensed too much food at once.
There was some spilling (which would cause a jam in the mechanism)

So for my next version I would use a smaller opening so that less food comes through at a time.  I would also have a smaller closed chute for the food to slide through. 
Maybe I would have some rubber or cloth hanging down a half-inch so that there would be a seal, but no food could get jammed between two hard moving edges. 

An alternative design would be to have a drawer that would slide forward and allow food to pour out the bottom. 
I've also seen a design where the entire drum of food spun around and a bit of food came out of a hole each time.

[Reply #3 on:]

Nice work on your first design!

I was just involved in a dispenser project where our team created a device that popped open one of its 6 containers every two months.  The goal was that we would stock these containers with mouse repellent and set it in a summer home so that the device could run autonomously and drop repellent every two months. 

One of our biggest issues, though, was keeping track of time throughout the year.  I know that the Arduino has it's own internal timekeeper, but after running it for an extended period, it's subject to either go out of sync or overflow and lose track of time (especially when running it for an entire year).

If you're planning on using leaving your dispenser to run for a few days, I'd recommend looking into a Real-Time Clock chip like the DS1307 or DS1337.  These devices communicate with the Arduino via i2c, and they can keep much better track of time than the internal timekeeper. 

(I've been using the DS1307 with an Arduino clock on the side for the past 6 months, and it hasn't gone off more than a minute or two since then.)