Picture of Automatic Pet feeder
I needed a reliable fish feeder for my pond for when I'm away.  This instructable gives details on the feeder that I just finished building and testing.  The same idea could be used for feeding other pets or for an indoor aquarium. I made a number of internet inquiries to find out details on the microwave carousel motor that I planned on using to drive the auger.  The problem with the motor is that it will often reverse rotational direction when it is turned ON and OFF and ON again.  I learned from internet contacts that a ratchet would solve the reversing problem so that is what I ended up using here.  A short demo near the end of the video (below) shows me stalling  the motor to reverse direction.  Some microwave carousel motors work directly from the line voltage in which case you wouldn't need a transformer.  However I feel comfortable with the lower voltage setup for this application as it gives an extra level of safety when the feeder is operated outdoors.  The electronic timer allows programmable  ON and OFF  times for the motor.  (Better still if you have or can find a gear head dc motor the rotation direction is controlled just by reversing the polarity of the connections.)

I decided to change the name of this instructable to Automatic Pet Feeder from Automatic fish feeder as viewers are using the idea to feed other things...

In any application like this it is important to plug the timer into a ground fault circuit interrupter (GFCI) electrical outlet.

Step 1:

Databanks6 months ago

One thing you may want to do in the future is replace the clear plastic tub with something more UV stable. Maybe give it a few coats of outdoor paint?

I've found they don't cope well with prolonged sunlight. Nice project overall and makes me wonder if it could have other applications. Bird feeders, rat feeders, etc. Nice work

nlinventor (author)  Databanks6 months ago
Thanks for the ideas. I've already made a bird feeder using the same idea - you can check it out here: http://youtu.be/xAMziIALZrA
(It has also served as a rat feeder :))
jeggeggo3 years ago
Hi, I am interesting in this project,I hope that you can give me the circuit diagram for this, I kind of need it for my college's project.Any help,really apreaciate.Thanks.
nlinventor (author)  jeggeggo3 years ago
Hi Jeggeggo - here's the wiring for the timer. Did it in two forms to help you out. My timer has two 110 volt outputs They are simply in parallel. One is for the microwave motor and the other is used to provide a resistive load to the timer - this gives reliable timer operation. If your timer has just one output, use a power bar to do the same thing. Let me know if you make one.
wow..that's really cool..thanks 4 help...got this press this evenight...
will give u a look when i make mine...
Amazing idea!!!
nlinventor (author)  Husham Samir3 years ago
Thanks Husham - the feeder has been working flawlessly in automatic mode for about three weeks now.
dimmaz883 years ago
Awesome instructable, I'll have to adapt for feeding a cat :)
nlinventor (author)  dimmaz883 years ago
Let me know if you get to make one for your cat and thanks!
Great idea. I did make a similar system to feed two cats. I used a 1" long auger bit inside a piece of 1" pvc pipe. Two notches in the top and two in the bottom allowed each cat's food to enter the auger pipe, transfer along a inch and drop out down a chute into their bowls. I had to build a funnel trough above to supply the food but it works great. I'm new to the site so hopefully I did this right and my pictures show up.... The first is from the top showing the auger in the tube, the second shows the outlet pipes dropping down and the third is the cabinet I put it in so it looks pretty.
Cat feeder1 (640x480).jpgCat feeder2 (640x480).jpgCat feeder3 (640x480).jpg
did you make an instructable for that because if you didnt you should
nlinventor (author)  amberger3 years ago
Real nice! Sorry for the late reply but I've been travelling. I'm able to monitor my feeder remotely on the internet and it has been performing flawlessly in automatic mode over the last three days. Kind of neat to see the feeder working from more than 4000 miles away! Do you have a video of your feeder in operation?
nlinventor (author)  gasel253 years ago
You're welcome! Glad I could help.
Boost3 years ago
I laughed out of joy when I saw you using a drill as an auger screw! Awesome instructable. It sounds like a lot of food bits get crushed. Is there a huge pile of fish food dust at the bottom when it has emptied the bin?
nlinventor (author)  Boost3 years ago
Not much dust at all - yeah it's kind of a pleasant sound actually, maybe something like Rice Krispies on steroids :)
marc.cryan3 years ago
Nice! What is the food?
nlinventor (author)  marc.cryan3 years ago
Thanks - it's Tetra Pond Food intended for Koi and Goldfish but I feed it to my pond trout to supplement the food they get from nature. I also feed them worms as an extra treat as I usually have plenty of worms around the compost area.