Planet Arduino

We often like to say that if something is worth doing, then it’s worth overdoing. This automatic cat feeder built by [krizzli] is a perfect example of the principle. It packs in far more sensors and functions than its simple and sleek outward appearance might suggest, to the point that we think this build might just set the standard for future projects.

The defining feature of the project is a load cell located under the bowl, which allows the device to accurately measure out how much feed is being dispensed by weight. This allows the feeder to do things such as detect jams or send an alert once it runs out of food, as well as easily adjust how much is dispensed according to the animal’s dietary needs. To prevent any curious paws from getting into the machine while it’s doling out the food, the lid will automatically open and close during the filling process, complete with optical sensors to confirm that it moved as expected.

All of the major components of the feeder were printed out on a Prusa i3 MK3S, and [krizzli] says that the feed hopper can be scaled vertically if necessary. Though at the current size, it’s already packing around a week’s worth of food. Of course, this does depend on the particular feline you’re dealing with.

In terms of electronics, the feeder’s primary control comes from an ESP8266 (specifically, the Wemos D1 Mini), though [krizzli] also has a Arduino Pro Mini onboard so there’s a few more GPIO pins to play with. The food is dispensed with a NEMA 17, and a 28-BYJ48 stepper is in charge of moving the lid. A small OLED on the side of the feeder gives some basic information like the time until the next feeding and the dispensed weight, but there’s also a simple API that lets you talk to the device over the network. Being online also means the feeder can pull the time from NTP, so kitty’s mealtime will always be on the dot.

Over the years we’ve seen an incredible array of automatic cat feeders, some of which featuring the sort of in-depth metrics possible when you’ve got on onboard scale. But we can’t help but be impressed with how normal this build looks. If nothing else, of all the feeders we’ve seen, this one is probably the most likely to get cloned and sold commercially. They say it’s the most sincere form of flattery.

We’ll admit it: we sometimes overcomplicate things. Look at [Peter Weissbrod’s] automated cat feeder, for example. It isn’t anything more than a bottle, a servo, some odds and ends, and an Arduino. However, it lets him sleep in without his cat waking him for service.

We looked at the code and thought, “This thing will just dispense food all the time! That’s not what you want!” Then we looked closer. [Peter] uses a common household timer to just turn the device on in the morning, let it run for a bit, and then turns it off. You can see a video of the mechanism, below.

Honestly, we have mixed feelings. As we are sure someone’s already quit reading to comment: you don’t really need an Arduino for this. If it were doing the timing, that might make it more justifiable. Or perhaps have it sense daylight to feed in the morning. Still, Arduinos are cheap (we just picked up some tiny Pro’s for about $3) and it is a more flexible arrangement than, say, a 555 driving the servo.

We have seen many cat feeders over the years. Some of them use custom components. Others use whatever you have on hand (including another kitchen timer). However you do it, one thing is clear: When the aliens come and observe life on Earth, they will doubtless conclude that the cats are in charge.

Tired of being harassed by your cat? [MomWillBeProud] made a cheap, effective — and more importantly cat-operated — cat food dispenser.

The feeder is of an efficient construction — a double cat food dish, one container to store the electronics, and a Pringles can to act as the hopper. A simple servo rotates the hopper thirty degrees and back on each button press; using gravity to drop food through an opening that appears due to this motion. The button itself is an old IKEA timer and a piece of plastic large enough for a hungry cat to swat.

An Arduino controls the servo, and while [MomWillBeProud] skips over going into detail on his code, you can check it out here.

[MomWillBeProud] toyed with the idea of scheduled feeding, but believes his cat is smart enough to feed itself; indeed — training cats is hard work, and it took a couple of weeks for the lessons to sink in. He also recommends using an Arduino Pro Mini, since it consumes so little power that it can operate for months on one set of batteries. Since [MomWillBeProud]’s cat needs a refill only once a week, that’s a lot less time fussing with one’s feline companions.

If you want a similarly hands-off method to ensure your pets have water, we previously featured a project that keeps your pet’s water bowl topped off.

[via /r/DIY]

[Domiflichi] likes his cats, but not the drudgery of feeding them. So, like any good engineer, this simple problem became his next project: building an automatic cat feeder. Based on an Arduino, his creation beeps to let the cats know that it is dinnertime, then dispenses food into a number of bowls. There are also buttons for manual control. This lets him give individual cats a separate feeding. Rounding out the feature set, a DS1307 RTC tracks the feeding times.

One of the most interesting parts of his build is the transfer from breadboard to protoboard. This usually involves taking apart a working version, then putting it back together and trying to figure out why it doesn’t work anymore. [Domiflichi]’s problem (detailed in a follow-up post) was figuring out how to program the real-time clock module to set the time, because it looses the time when you disconnect the power. Rather than use the Arduino to program the RTC,  he used the battery backup feature of the RTC chip, programming it on his computer and then soldering it onto the board. He went on to remove the backup battery after the chip was in place. That’s a solution that will no doubt have many readers waving their fingers disapprovingly, but it worked.

It may seem overly complicated, but his project is worth checking out to see how he approached some of the engineering challenges. The food hoppers themselves are off-the-shelf cereal dispensers. We’ve seen other designs bootstrap this mechanism with 3D printed augers.

We’ve seen automated food dispensers for pets, but none that go so far as to build large plastic screws for dispensing kibble.

This isn’t [Mathieu]‘s first automatic cat feeder; an earlier version used a wheel to dispense cat food in excessively large version. To improve upon his first build, [Mathiu] decided to use an Archimedean screw to dispense food in 5 gram increments. There was a problem, though: a proper industrial screw cost about $1500 and the ‘consumer’ versions of what he wanted were trash. He though about casting one in epoxy but didn’t want to poison his cat with strange chemicals. He ended up using PolyMorph for his screw, a plastic that melts at 60º C and is also used in medical devices.

The electronics of the build are an Arduino, a  DS1307 real-time clock, LCD display, and a relay board powering an electric screwdriver motor. From the video demo below, we’re going to say [Mathieu] put together a pretty nice automated cat feeder.