In order to feed the fish automatically, we needed to devise a mechanism by which we could digitally control the dispensing of food into the aquarium. The device we constructed consists of a circular device with 24 compartments, each of which can hold some food. This is placed over a piece of plexiglass which contains a feeding hole.
A stepper motor rotates the compartments and as each compartment passes over the feeding hole, the food in it falls into the tank.
The plastic portion consists of the bottom of a plastic flower pot and the bottom of a plastic cup. Plastic dividers were notched and glued into place with Epoxy.
The stepper motor is controlled by cycling through 4 combinations of control signals: 1010, 1001, 0101, 0110. Because the motor draws so much current, it is powered off its own power supply and an interface board must be used to buffer control signals from the HC12.
