Auto-Feeder (For the Cats..)


 I started off the project with the idea in mind that I was going to do some minor modifications to my automatic fish feeder. I quickly had problems with that setup because the cat food pieces were much larger than the fish food pellets. The auger blades weren't large enough to push the cat food through very well, and since I was just using a sweeping servo I thought that I might be able to push more food through if I re-geared the servo to continuously rotate. So I dremeled away at one of the servo gears but of course once I tested it I realized that the auger bit wasn't going to cut it.

    So I tried using one of my salvaged steppers from an old laser jet printer. It had a little metal gear already attached and I didn't have much luck removing it with the blow torch so I just hoped that epoxy would hold the auger onto the motor, which it did more or less. I tried just epoxying the entire thing together with an emptied out spaghetti jar but it was just another pretty embarrassing attempt at making a feeding mechanism. If I had more tools or more space for machining and tools then I would have tried making something else but I finally just gave in and paid $22 for a cereal dispenser (probably saved me several hours of frustration).

    I attached a stepper motor that I had bought from Adafruit  with a circular hub unto the cereal dispensers handle. It took a few tries to level it, and I was really afraid of seizing the motor if the axle and handle were unaligned; but it seems to be holding well. I only attached the dispenser with a zip tie and a hose claim. I tried leaving some slack just to avoid any binding of the motor shaft since the shaft and dispenser handle aren't perfectly aligned.

    I wanted the unit to be activated from my bed so I could trigger the feed unit from my bed. This was so that on Saturday/Sunday at 6am I could just lazily trip the sensor with my laser pointer instead of getting up. I thought about using an RF sensor, but ultimately decided that a green laser pointer is much cooler and it also double as another device for distracting annoying cats when they're in your face. So I wired up a couple light intensity sensors to an Arduino and compared analog values of different types of light to determine what would be tripped by the green laser vs. the sunlight (For the record, I didn't do a great job testing. Probably should have actually used the sun.. )

    I also added a button to press for feeding and create a simple function to read serial signals so that I could write another program to feed the cats on a timer, or to feed them when I was away from home.