The CatGenie is an amazing device to watch in action, basically a self-cleaning litter box for cats that even does away with the need to replace the litter. It’s comparable to what the indoor flush toilet is for humans compared to maintaining a composting toilet. However, there is a problem. It uses costly soap cartridges which have to be replaced because an RFID reader and a usage counter prevent you from simply refilling them yourself.
The RFID reader board communicates with the rest of the CatGenie using I2C and he needed to know what was being transmitted. To do that he learned how to use a cheap logic analyzer to read the signals on the I2C wires, which makes this an interesting story. You can see the logic analyser output on his blog and GitHub repository along with mention of a timing issue he ran into. From what he learned, he wrote up Arduino code which sends the same signals. He and his cat are now sitting pretty.
What he didn’t do is make a video. But the CatGenie really is amazing to watch in action as it goes through its rather complex 30-35 minute process so we found a video of it doing its thing, shown at 3.5x speed, and included that below. If you’re into that sort of thing.
[Jorge] moved into a new apartment with a feline companion and wanted one of those fancy, auto-cleaning litter boxes. Apparently only one such device exists, the CatGenie. This ‘Rolls Royce of cat litter boxes’ uses little pieces of plastic granules as ‘functional medium’ that are scooped up, cleaned, and returned to use. These granules are washed with a cartridge full of fresh-smelling cleaning solution that comes in a container with an RFID tag. Yep, DRM’ed cat boxes. Welcome to the future.
After cruising around the Internet, [Jorge] found a CatGenie community that has released open source firmware for a litter box and something called a CartridgeGenius, a drop-in replacement for the cartridge tag reader in the litter box. It simulates both the RFID tag and its reader, allowing any robotic litter box owner to select between 120 cycle cartridges, 60 cycle cartridges, a maintenance cartridge, and set the fill level of those cartridges.
Previously, [Jorge] was spending about $350 a year on the solution to clean these plastic granules, so in a few months this CartridgeGenius has already paid for itself.
How can you not be interested in a project that uses load cells, Bluetooth, a Raspberry Pi, and Twitter. Even for those of our readers without a cat, [Scott’s] tweeting litter box is worth the read.
Each aspect of this project can be re-purposed for almost any application. The inexpensive load cells, which available from eBay and other retailers, is used to sense when a cat is inside the litter box. Typically sensors like the load cell (that contain a strain gauge) this use a Wheatstone bridge, which is very important for maximizing the sensitivity of resistive sensor. The output then goes to a HX711, which is an ADC specifically built for load cells. A simple alternative would be using an instrumentation amplifier and the built-in ADC of the Arduino. Now, the magic happens. The weight reading is transmitted via an HC-06 Bluetooth module to a Raspberry Pi. Using a simple Perl script, the excreted weight, duration, and the cat’s resulting body weight is then tweeted!
Very nice work! This is a well thought out project that we could see being expanded to recognize the difference between multiple cats (or any other animal that goes inside).
Cat poo stinks. We all know it. Those of us who have cats, though frequently amazed at the sheer magnitude of stench our cuddly friends are capable of, do little to remedy the situation. Sure, sometimes we buy the fancier kitty litter or the special food. [agraham999] decided to be a little more proactive. He built an automated exhaust system for the litter box. He wasn’t content to just rig a fan blowing to an exhaust vent either, he hooked it up to an automation system and a motion detector. The total cost for the project was $80, not including the mac mini that serves as the brains.
Be sure to read through the comments for some very in depth discussion about power usage and solar conversions.