This thing is designed to move kibble through a standard PVC pipe. The cat food drops down from a storage hopper through a vertical T and is pushed laterally through a pipe into the food dish. Includes a laser fence to cut off the motor when the kibble reaches the top of the bowl. Another Fence to sense if the hopper is empty
I created a couple of flanges to allow it to be mounted to plywood and a standard hobby servo motor. The servo should be modified for continuous rotation. A standard DC motor would also work, but I like that a servo is pre-geared for torque. Makes my life easier. I recommend HiTec MG series servos for better torque
This is an early print on my makerbot and you can see there is some edge curling, but I doubt my cat will complain.
I have a replicator 2 now, but don't want to reprint just for aesthetics
Updated 2-5-13: Project Complete!
This system uses a custom Auger and Servo to drive the cat food sideways into a bowl with a laser fence for volume control.
The parts were printed out a long time ago on my Thing-O-Matic, but sat in the garage for a long time because I couldn't figure out how to do the hopper correctly. I had wanted to be able to load several bags of food with no worries and also avoid jamming. This was a problem that has been solved in this design
The auger is split in half, so you need to print the whole thing out,and glue them together using some kind of glue, commenters have suggested PVC or plastic cement. Thanks to Miserybot for suggesting interlacing the auger to reduce print area.
Select a servo horn and drill holes in the base of the auger that will match up with it. be sure the auger is mounted in the exact center of the horn. Attach the horn first and then use the holes in the back of the servo flange to mount the auger to the horn.
Note that in my design, the auger is smaller in diameter than the outside of the T. The outer diameter of the auger would fit perfectly in the inner pipe, but having it float in the center of the T will help reduce binding from the cat food or whatever you are driving.
The build files are all included in sketchup format, as well as the fully commented arduino code.