Snack Timer For Buffy The Cat

Buffy tends to overeat if all her food ration is presented at once so now she gets 4 small meals instead of two larger ones. But how can these meals be served at even intervals in the 24-hour day?

One can always search for and buy an automatic cat feeder but I opted for a D.I.Y solution using an economy AC timer and junk box parts. My design has an easily cleaned metal food tray with no plastic to capture bacteria and odors.

The idea of the design is to have to have a simple “tip-over” dispenser that is held up by a tiny pin. When the timer applies power, the pin is pulled aside allowing gravity to tip the dispenser which drops kibble into the food tray.

The following photo shows a pill bottle attached to a computer hard disk drive which has the electronics and platter removed. The tiny head guides cannot be seen since they are bent straight upwards to catch a piece of ty-wrap plastic glued to the bottle bottom. Now it is ready for the next snack.

The next photo shows the bootle has tipped allowing the food to slide down an improvised ramp into the food tray. The ramp is a strip of plastic cut from some off-the-shelf product box. The food tray is part of a welded “cat sculpture” found at a kitchen store. The dispenser is attached to two scraps of particle board shelving. And the whole assembly sits in a cheap platic tray (blue) which captures dropped kibble for easy cleaning.

Next, I describe the simple electrical pin-release circuit for those who know what “diode” and “capacitor” means. The hard disk drive contains a powerful magnet which is positioned over the moving coil which is part of the head positioner assembly. Current flow causes the coil to move relative to the magnet. The pin release circuit consists of 4 parts:

  • an AC timer
  • an AC/DC power pak which supplies at least 3volts to 6volts
  • a 2200uf 10v capacitor (but 470uf may work)
  • a rectifier diode
  • a 10k resistor.

3v input — diode +++++ cap —- coil —- 3v return

When power is applied the capacitor charges through the coil which deflects the positioner upward momentarily. The 10k resistor is connected across the capacitor to drain it slowly when the power is off.

Finally, here is a photo of an economical AC timer. I set mine for brief operation at 3pm and 4am.

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