cats

17 Articles

RFID From First Principles And Saving A Cat

November 23, 2024 by 5 Comments

[Dale Cook] has cats, and as he readily admits, cats are jerks. We’d use stronger language than that, but either way it became a significant impediment to making progress with an RFID-based sensor to allow his cats access to their litterbox. Luckily, though, he was able to salvage the project enough to give a great talk on RFID from first principles and learn about a potentially tragic mistake.

If you don’t have 20 minutes to spare for the video below, the quick summary is that [Dale]’s cats are each chipped with an RFID tag using the FDX-B protocol. He figured he’d be able to build a scanner to open the door to their playpen litterbox, but alas, the read range on the chip and the aforementioned attitude problems foiled that plan. He kept plugging away, though, to better understand RFID and the electronics that make it work.

To that end, [Dale] rolled his own RFID reader pretty much from scratch. He used an Arduino to generate the 134.2-kHz clock signal for the FDX-B chips and to parse the returned data. In between, he built a push-pull driver for the antenna coil and an envelope detector to pull the modulated data off the carrier. He also added a low-pass filter and a comparator to clean up the signal into a nice square wave, which was fed into the Arduino to parse the Differential Manchester-encoded data.

Although he was able to read his cats’ chips with this setup, [Dale] admits it was a long road compared to just buying a Flipper Zero or visiting the vet. But it provided him a look under the covers of RFID, which is worth a lot all by itself. But more importantly, he also discovered that one cat had a chip that returned a code different than what was recorded in the national database. That could have resulted in heartache, and avoiding that is certainly worth the effort too.

Continue reading “RFID From First Principles And Saving A Cat” →

CATS mobile transceiver in a 3d-printed case

CATS: A New Communication And Telemetry System

March 15, 2024 by 29 Comments

CATS is a new communication and telemetry standard intended to surpass the current Automatic Packet Reporting System (APRS) standard by leveraging modern, super-cheap Frequency Shift Keying (FSK) transceivers rather than standard FM units. The project is in the early stages, but as of this writing, there is a full open source software stack and reference hardware for both Raspberry Pi-based gateway devices and an STM32-based mobile device.

CATS packets are called ‘whiskers!’

From a radio perspective, CATS uses raw FSK rather than the inefficient AFSK used by APRS. A real killer for channel utilization is the PTT time; this is the dead time around a packet APRS requires for ‘keying up’ and ‘keying down.’ The CATS standard is aggressive with PTT timing, enabling the channel to get going on sending the data sooner.

Additionally, compared to APRS, the packet baud rate increases from 1200 baud to 9600 baud. Other key points are using LDPC encoding for forward error correction and data whitening (a useful PDF guide from Ti) to smooth over any burst errors.

One of the neat concepts of APRS is the APRS-IS (APRS Internet service). This enables amateur radio services to be connected over the Internet, vastly improving range. The CATS equivalent is called FELINET (if you’re not spotting all the ‘cat’ references by now, go and get another coffee). Together with the I-gate hardware, FELINET bridges the CATS radio side with the current APRS network. As FELINET expands to more than the current few dozen nodes, APRS services will no longer be required, and FELINET may well replace it. Interestingly, all software for FELINET, the APRS relay, and the I-Gate firmware are written in Rust. We told you learning Rust was going to be worth the effort!

On the reference hardware side of things, the CATS project has delivered a Raspberry Pi hat, which uses a 1 watt RF4463 transceiver and supporting passives. The design is about as simple as it can be. A mobile transceiver version uses an STM32 micro to drive the same RF4463 but with supporting power supplies intended to run from a typical automotive outlet. Both designs are complete KiCAD projects. Finally, once you’ve got some hardware in place and the software installed, you will want to be able to debug it. CATS has you covered with an RTL-SDR I-Gate module, giving you an independent packet log.

APRS is quite mature, and we’ve seen many hacks on these pages. Here’s an earlier APRS IGate build using a Raspberry Pi. Need to hook up your PC to a cheap Chinese transceiver? You need the all-in-one cable. As with many things amateur-radio-oriented, you can get playing cheaply.

A cat sits on a dark green mid-century modern bench next to a cat-sized black piano. A black bowl sits beneath the piano to catch food. An abstract green, blue, and tan picture in a black frame is on the wall above the cat and a black bar stool can be seen around the corner. It looks like the sort of photo you'd see on Instagram or in an interior design magazine.

Piano Feeder Gets Pets Playing For Their Supper

February 29, 2024 by 21 Comments

If you ever watched a video of Piano Cat and wondered if your cat could learn to play, then [Sebastian Sokołowski] has a possible solution with this combination piano tutor and cat feeder.

Starting with a CNC cut MDF enclosure, [Sokołowski] developed a cat feeder that would fit in the rear of the piano. It had to be reliable, consistent, and easy to disassemble. He walks us through his testing for each of these features and says the feeder was the most difficult part of the project to develop due to the propensity of pet feeder mechanisms to jam.

A custom PCB takes the key presses from the piano (with functional black keys) and outputs the sound from a speaker in the back. Lessons progress through increasing difficulty automatically, encouraging your cat to learn what the different keys can do. Food is dispensed after a performance or on a schedule set through the accompanying smartphone app. All the files are available if you want to build your own, but there is a wait list available if you want a completed version to give to less technically-inclined cat staff.

We’re certainly no stranger to the creatures that rule the internet here at Hackaday, having featured other cat feeders, new research into spaying cats, or even open source robo-cats.

Continue reading “Piano Feeder Gets Pets Playing For Their Supper” →

Cat-o-Matic 3000 Serves Your Feline Masters

December 1, 2023 by 8 Comments

When you have three cats and three humans, you have one problem: feeding them on a schedule without over or under feeding them. Even if there was only one human in the equation, the Cat-o-Matic 3000 would still be a useful tool.

Essentially, it’s a traffic light for cats — where green means you are go for feeding, and red means the cat was just fed. Yellow, of course, means the cat is either half-full or half-empty, depending on your outlook.

The brains of this operation is an ATmega88PA leftover from another project. There’s a no-name voltage regulator that steps up the two AA cells to 5 volts. Timing comes from a 32 kHz crystal that allows the microcontroller to stay in power-saving sleep mode for long periods of time.

Creator [0xCAFEAFFE] says the firmware was cobbled together from other projects. Essentially, it wakes up once per second to increment the uptime counter and then goes back to sleep. Short-pressing a button shows the feeding status, and long-pressing it will reset the timer.

Wanna make a cat status indicator without electronics? Give flexures a try.

Spaying Cats In One Shot

June 12, 2023 by 61 Comments

Feral cats live a rough life, and programs like Trap, Neuter, Release (TNR) attempt to keep their populations from exploding in a humane way. Researchers in Massachusetts have found a non-surgical way to spay cats that will help these efforts.

A single dose of anti-Müllerian hormone (AMH) gene therapy suppresses ovarian follicle formation, essentially turning off the ovulation cycle. After following the test cats for two years, none had kittens, unlike the cats in the control group. Other major hormones like estrogen were unaffected in the cats and they didn’t exhibit any negative side effects. The researchers said it will be some time before the treatment can be widely deployed, but it offers hope for helping our internet overlords and the environs they terrorize inhabit.

For those of you doing TNR work, you might want to try this trap alert system to let you know you’ve caught a cat for spaying or neutering. If you’d rather use a cat treat dispenser to motivate your code monkeys, then check out this hack.

Cat Feeder Depends On RFID To Keep The Peace At Dinnertime

February 28, 2023 by 10 Comments

Anyone with more than one cat can tell you that the joy mischief they bring into your life is much more than twice that of a single cat. And if those felines have different dietary needs, you can end up where [Benjamin Krejci] found himself, which resulted in this fancy RFID cat feeder.

For a little backstory, [Ben]’s furry friends [Luna] and [Fermi] have vastly different eating styles, with the former being a grazer and the latter more of a “disordered eater,” to put it politely. [Fermi] tends to eat until she vomits, which is fun, and muscles her pickier sister away from the bowl if there’s anything left in it. [Ben]’s idea was to leverage [Luna]’s existing RFID chip, which he figured would be a breeze. But the vet-inserted chip is designed to be read by a high-power reader directly in contact with the cat’s skin, which made reliably reading the chip a challenge.

Several round of design iteration resulted in the current configuration, with a large antenna coil poised above and behind the food dispenser. [Luna] has no choice but to put the back of her neck and shoulder blades almost directly in contact with the coil, which makes it easier to read the 134.2-kHz chip with a long-distance RFID module. If [Luna]’s chip is found, the lid on the food bowl opens gently and quietly, so as not to spook the mild-mannered cat. The lid stays open as long as [Luna] is in place thanks to some IR sensors, but as soon as she backs out, the lid comes down to keep [Fermi] from gorging herself.

Hats off to [Ben] for working through the problem and coming up with what looks like a fine solution. We suppose he could have tried something easier like weighing the two cats to distinguish between them, but this seems like a cleaner solution to us.

An orange and white cat eats from a bowl with a hinged cover. The cat and the bowl are on top of an MDF platform.

Load Cells To Get The Right Pet The Right Food

September 18, 2022 by 11 Comments

If you have more than one pet, you may know how hard it is to tell how much each furry friend is eating. If you introduce prescription foods, then this minor annoyance can have a major impact on your pet’s health. Facing this dilemma, [tomasdiazwahl] set out to make a pet feeder that feeds his pets exactly what they need when they approach the feeder.

Using the ever-popular Arduino Uno, the feeder is connected to a platform that uses load cells to detect the pet’s weight. The weight data is then used to identify which animal is looking for food. Once the pet is identified, the correct food bowl opens. It seems this prototype only has one food chamber to keep unauthorized pets from eating the special food, but the basic idea should be extensible to two or more chambers. While some existing solutions read the pet’s microchip or NFC collars to determine who’s at the feeder, [tomasdiazwahl] decided against these given the fickleness of trying to reliably get a reader at the correct position relative to the pet. As long as you don’t have multiple pets with the same weight, it should work just fine.

This project has a nice mix of woodworking, 3D printing, and electronics showing what can be accomplished when you aren’t afraid to mix techniques. We also really appreciate that [Tomasdiazwahl] spent the extra time to include a testing procedure and safety mechanism into the project. Designing a device to improve your pet’s health shouldn’t come with a safety risk!

This isn’t the first cat feeder we’ve covered that uses weight to tell the difference between the pets, and if you want a simpler project to start with, check out this Simple Auger Pet Feeder.