If you have an indoor cat, you’re probably all too familiar with the litter box-changing process: You peek and sniff at the litter box, and if you encounter a grim sight or bad smell—it’s time to change the litter. Once you build your own smart litter box sensor, your cue becomes a blinking light and a text message. Much nicer, right?
Check out the video above to see it in action. And look below for some shots from the prototyping process.
As adults, we have the right to only be responsible for our own poop. But when you own an indoor cat, you give up that right. Your cat’s poop becomes your responsibility.
It’s never fun to find out that it’s time to change out the litter in your cat’s indoor bathroom (i.e. litter box). Smell is the key indicator, and who likes to sniff around for a bad smell?
Enter, the smart litter box sensor:
The sensor detects the excess ammonia gas emanating from an uncleaned litter box. In response, it has two outputs: it lights up two LEDs (behind each eye in the little kitty head), and it sends an SMS (text message) to the keepers of the litter box (i.e. the pet’s owner(s)/parent(s)).
I’ve already prototyped a non-texting version of this product:
< Sketch of wiring diagram for sensor, 2 LEDs and Arduino board
< Soldering/wiring process for sensor and LEDs
< 3D-printed enclosure for the sensor, LEDs and wires (it’s too small!)
And now it’s time to add the text-sending functionality to the equation. This will require:
A WiFi-capable circuitboard, like the Huzzah Feather (already purchased)
Getting my existing code to work on this new board (work in progress!)
Adding a text-sending functionality by parsing through how-to guides like these:
I’m developing a fume-activated litterbox monitor (i.e. “your cat’s box smells bad! time to clean it!”). I’ve devoted this first prototyping to achieving full functionality in my sensor in the breadboard phase. As you can see* in the video below, I have:
Here’s a clearer look at my breadboard wiring:
And here’s a glimpse into the process whereby I concocted a water-ammonia solution with roughly the same ammonia levels as cat urine:
Healthy cat urine is allegedly .05% ammonia, among other things. So I combined 2 liters of water with 1 milliliter of ammonia to simulate cat urine. However, this concoction was too mild to impact the gas sensor enough to create a spike in the serial output, so I ended up just doubling the “resting” threshold as my “stinky-enough” benchmark.
Here are my envisioned next steps:
Incorporate a smaller Arduino board for a sleeker profile
Consider the inclusion of a WiFi-capable Arduino board, explore transforming output from LED ignition to SMS sending (i.e., “time to clean the litterbox!”)
Develop a chassis that can encompass all these components, convey the utility (cat-shaped?), and inspire admiration
Please let me know your thoughts or suggestions in the comments!