The most hydrated dog on the planet

Maple has one rule: the water bowl is never empty. If it is, she goes nuts until somebody fixes it. She is, without question, the most hydrated dog on the planet, and she would like to keep it that way.

So I built a water sensor for her bowl, so we can refill it before Maple has to file a complaint.

How it works

• No wires in the water. A capacitive, non-contact level sensor sits on the outside of the bowl and senses the water through the wall.
• It waits before it panics. The bowl has to read dry for 30 seconds before it counts as empty, so a long drink doesn’t set it off.
• Three ways to nag. A red LED lights up, a little piezo plays a song (muted overnight), and our phones get a push notification: Maple’s water bowl is empty. If nobody refills it, it asks again every two hours. When the water’s back, it sends Refilled, all good and the green LED comes back on.
• A 3D-printed case. An ESP32 on perfboard, powered over USB-C, in a case I designed in OpenSCAD. It took three test prints to get the cable slots right.

Feed Maple

Once the sensor was talking to our phones, the next step was obvious: dinner. Feeding Maple is now part of our household routine on Side Quest. The devices remind whoever’s on duty, and checking it off on one tells everyone else it’s done, so Maple doesn’t get two dinners (her preference) or none (her nightmare).

Not everyone in the house has a Side Quest, so there’s also a one-page Feed Maple web app with a big “I fed Maple” button. It talks to the same system, so a meal checked off anywhere shows up everywhere.

Maple has not noticed any of this. She just wants water and dinner, on time, forever.