Needed an aquarium feeder for when i go on holidays so I made this one, can also be used on a day to day basis. It's meant to feed shrimp and fish so I'd fill all the pockets with fish food to feed daily and alternate for the shrimp.

The mechanism consists of a rotating barrel powered by a servo with an arduino for a brain to make the servo rotate every 24h. Of course other configurations can be set in the code.

The top lid is magnetized (3x1mm) for easy of access to the food pockets. 
The rotating part is screwed to the servo on top by the screw that came with it (keep in mind that the rotating part consists of two parts, the barrel and the pivot, you're supposed to glue the later and use the servo as a aligner. I made it two parts so that you can print them with the face down and reduce friction).
The servo will fit very tightly (to prevent it from moving) in it's place and has an screw hole in case you want to keep it extra secure but the overall fit is enough.
The bottom lid is secured with 3 M3x16 to keep the electronics inside, I also used 3 heat inserts but they're not absolutely necessary.

For printing print with 3 walls and 15% infill, if you have a smooth plate print there cause the smooth finish reduces the friction and helps the rotation. I printed in PLA because I didn't have ABS available and it was not going to be in contact with water but I advise you to print in ABS.