As a former dog owner and first time cat dad I was amazed at how cats are "potty trained" practically from birth. I was prepared to deal with the smell when having to clean the litter box. However, I didn't expect their bowel movements (💩) to carry a punch that would stink up half my apartment.
This might not be the case for everyone, but certainly for me, with an indoor cat in a 2 bedroom apartment without a naturally ventilated place to keep her litter box.
The hero/villain of the story
Her name is Dua and she is a cuddly & playful rescue tortie cat. Dua loves to play with her mouse toys and adores wet food, the latter of which is likely the reason I'm writing this post 😵💫
I have her litter box in my second bathroom's shower. The bathroom has an extractor fan that runs when the bathroom light is on, but she refuses to hasn't figured out how to turn it on and off each time she goes #2... Annoying, right?
Automating the extractor fan
To mitigate the smell I wanted the lights to turn on when Dua goes in her litter box. To do this I put together a few things:
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RaspberryPi Zero W
- WiFi support was the goal
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PIR motion sensor
- Placed on the bathroom wall with "velcro stickers"
- Smart switch for bathroom lights (any brand will do) paired with an Alexa
-
Voicemonkey webhook to trigger an Alexa routine
"Alexa, turn on the switch for 5 minutes"
The software that calls the webhook (which in turn triggers the Alexa routine) can be found here:
fdocr
/
pir_trigger
Script that connects a PIR Sensor to a webhook
PIR Trigger
Script that connects a PIR Sensor to a webhook.
Usage
Clone the repo in a folder, install dependencies and then run in background
# Install requirements
pip install -r requirements.txt
# Run in background
# TODO: Find/Document a better way to do this
TRIGGER_URL="<webhook_url>" python main.py &
Otherwise add TRIGGER_URL = "<webhook_url>" to an .env file and the script will pick it up.
The script writes its own PID to pid.txt so it can be used. Examples:
# Follow output of background process
tail -f /proc/$(cat pid.txt)/fd/1
# Kill process
kill -9 $(cat pid.txt)
Sensor to board connections
The script was inspired by this Raspberry Pi Foundation article and uses their suggested example layout. The sensor needs 5v (Vcc) and Ground (Gnd), so PIN 2 and PIN 6 work well. Connect the sensor's output (Out) to…
It works!
Here's what the hardware looks like in action
💩 Stats
With all of this in place I went a step further and added Opentelemetry to track the stats of how often the routine was being triggered on Honeycomb.
I wanted to know if I was turning on the bathroom lights over false positives from the motion sensor, but after some tests it simply serves the purpose of telling how often she goes in her litter box.
Interestingly, I can tell she goes in her litter box (# of motion sensor triggers) on average ~8.5 times per day. I don't think many cat owners can say they know this about their feline friends. I do remember and took inspiration from Aaron Patterson doing something similar a long time ago though.
Anyways, that's it. Pura vida!
Top comments (14)
This is freaking AWESOME... and hilarious too! Nicely done, Fernando. 🙌
Also, while the stats section may seem a bit silly, my wife (a veterinarian as you know) said that when a pet gets blocked it often goes undetected until the pet vomits or shows extreme signs of discomfort. If you're able to see how frequently (or rather infrequently) your cat is going, you're more likely to know if she is no longer regular and then you know to take your cat in for a checkup. So, the stats are kind of a health perk!
I didn’t consider the health/vet’s perspective and now feel less silly for keeping track of those stats haha thanks Michael (and Katelyn too lol)! 😁
Incredible application of IRL observability! 😅
Your style of writing is awesome and and very engaging ha ha ha ha
Thanks! Glad it was a fun read 😄
Man, I wish I thought of that when I had a cat. Of course, when I had a cat I was a teenager in middle school and only cared about how many Mama Celeste pizzas I could eat in a sitting. That's brilliant.
You're not alone in the RAW POWER of your cat's displays of dominance aka:💩!
Our cat has movements like a beast man! and rarely covers them. Just to tell us who is in charge.
I love the project, great!
LOL thank you for this.
😁
interesting post lmao
Given the title, I thought you were going to tell us how your cat learned to use the Raspberry Pi 😜
Nice idea.
I can heavily recommend you look at home assistant for this kind of stuff. It can make all your automation work locally (so no internet needed, and no amazon data collection) and you could do this with no code (or soldering, if you used zigbee sensors/switches) needed. I've been really enjoying using it for random (and cloudless) home automation stuff, the quality of HA is much better than it has any right to be.
That said, love the idea, and I might have to get a zigbee motion sensor for my cat boxes.
Home assistant was something I considered and will likely play with in the future. I didn’t know about zigbee devices, they seem cool. Thanks for the suggestions!
Good luck trying it out for your cats. I would love to read about that setup in the future if you’re ever interested in a write up afterwards 🙌🏼
Keeping up with your cat's what?