Opto-Isolating Automatic Cat Feeder Problems

When you buy an off-the-shelf automatic cat feeder, you might well expect it to do the one thing it’s supposed to do. Feed the cat. Well, at least as long as you do your part by keeping it filled with food nuggets. [Stephen] had the sneaking suspicion that his feeder was slacking occasionally, and set out to prove this theory.

He had a few ideas for approaching the investigation. One was to set up a web cam, but that proved unreliable. Another idea was to log the weight changes of the food bowl. This seemed like a possibility because the reading would change dramatically whenever it was filled. The method he settled on is a good one, too — monitor the motor’s activity and look for holes. After all, the motor only runs when it’s feeding time.

The design is based around a smart door/window alarm, which is little more than a reed switch with networking capabilities. [Stephen] wired up an opto-isolator so that when the motor runs, the reed switch is triggered but not fried, and the event gets logged in Google Sheets. Any missed meals are weeded out with a script that alerts [Stephen] via email and text that his poor kitty is hungry.

If [Stephen] ever wants to build his own cat feeder, we have plenty of designs for inspiration.

22 thoughts on “Opto-Isolating Automatic Cat Feeder Problems

  1. II’ve hacked a similar feeder to talk MQTT, and came across a similar problem while debugging. It’s not that it won’t be dispensing: when the food gets to about 1/3 full, the lack of pressure on the kibble means not as much is pushed into the mechanism as usual.

  2. I’ve always just left dry food out for my cats and they eat when they want. I’ve never had them get fat or had other problems, other than when some mice moved in and started eating it too. That was short-lived for obvious reasons. I managed to trap and save a couple, but not all of them, unfortunately.

    1. congratulations on having a cat that is different from other cats.
      my cat will eat as much ch food that is left out for her- always- regardless of amount.
      hey congratulations to me for having a different cat than yours…
      : /

  3. Does it ever say anyplace that he actually discovered that the feeder was intermittent? It says that he was suspicious that it was, but I have yet to find results. So we don’t know if there is really a problem or if there is just too much worrying going on. Given that data the next step is deciding whether to fix it or build a new one.

    Interesting idea though repurposing the door/window alarm. I can see turning this into my mailbox arrival gadget I think about making.

    1. It’s more that wet food is better for cats with those problems. Dry food does not cause these problems.

      Also, you can periodically give them wet food when you’re home. When you’re away for a day…trust me, if they get hungry, they’ll eat the dry food.

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