I made an e-collar, making Kaya is the world's first WiFi enabled K-9!
My staffy Kaya had a light-up collar that has unfortunately broken. It wasn't that great in the first place, single LED with an optical fiber and a 150mAH battery which lasted a couple of hours. I did what any engineer worth their salt would do and improved it! I used an ESP32 module with a LiPo controller and a 18650 3500mAH cell. For the lighting I used an addressable LED strip (outdoor version) and the FastLED library.
She now has a vibrant animated multicolor collar, with WiFi, lasting about 7-8 hours on a full charge and full brightness. It's not too bulky, she's not complaining and she's certainly enjoying the attnetion!
What's the WiFi for, you ask? Well aside from the "you're {bleep}ing me!" factor: it can be used for rudimental passive ranging and location. When connected I can use it to locate Kaya if she wonders of, within a moderate range.
Hey! Kaya was featured on Hackaday! Woof Woof! I mean, thanks!