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.
All of the collars are drill bit stop collars. I got some of these in a set and they cost only a dollar or so each. The collar used in the ratcheting system is also a drill bit stop collar, but it was selected for the ratchet because of the way the screw extends (tangent like) from the collar.
I've conducted multiple indoor tests running the motor for long periods to see how it would react with the 16 volt doorbell transformer. The temperature rise was barely noticeable and the motor torque was more than sufficient in all of the tests.
The pond testing went well and the fish quickly adapted to the new feeding method. I used a larger plastic bin to protect the feeder from the weather and critters (mainly crows and cats). But I can't knock the crows as they have been cleaning up food pellets that the fish didn't eat .