As a (former) cat owner for many years, this project arose from of my increasing dislike with the time it took to clean and maintain the pet drinking fountain I had. I wanted to return to a standard water bowl again and have it automatically filled with water:
- quick to clean
- no need to purchase filters
- smaller volumes of water meant fewer worries of water stagnating
- push notifications sent to my phone
The Fusion 360 file is included. I printed the spout in ABS in three parts so I could solvent weld them together and then vapour smooth them to be water proof. The light ring was printed in a transparent PLA. While the base could be printed (assuming your print bed is large enough) I opted to make it out of plywood and a 1:1 paper template is included.
| quantity | parts |
|---|---|
| 1 | Arduino Nano |
| 2 | NRF24L01 |
| 1 | N-Channel Mosfet (SUP75N06-08) |
| 1 | Flyback Diode (1N4004) |
| 3 | NPN Transistors (BC548) |
| 1 | 5V Voltage Regulator (LD117AV50) |
| 1 | 3.3V Voltage Regulator (LD117AV33) |
| 1 | 12V RGB LED strip segment |
| 6 | capacitors |
| 6 | resistors |
| 2 | RJ45 breakout boards or keystone jacks |
| 1 | DC Barrel Jack |
| 1 | 12V Power Supply |
| 1 | 12V Solenoid Valve (!NORMALLY CLOSED!) |
| 1 | 15mm equal isolating tee |
| 1 | 15mm x 1/4" compression straight adaptor |
| 1 | 10mm barbed fitting to 1/4" BSP |
| 1m | 3/8" ID, 1/2" OD Hose |
| 1 | small tension spring |
| 2 | M5 nuts |
| 2 | M5 pan head screws |
It's worth mentioning that I made this project around 2012 which is why the NRF24L01 module is used for communication (the first ESP8266 was released a few years later). If I were redeploying this again today I would opt for a single ESP32 board and set it up for MQTT.
Like most UK bathrooms I didn't have a convenient socket nearby, so, while the fountain resided next to my bathroom sink (plumbed into the cold water line), the circuit and power supply were in an adjacent room; the fountain was connected by an ethernet cable (hence the RJ45 adapters) and the solenoid valve was connected using 2 core speaker wire.
The arduino sketch is set up as a finite-state machine with two primary inputs; one to detect if the bowl is present and another to detect if the bowl contains water. Two secondary inputs are available for setup and testing; one allows to you set the "water filling time" at the fountain and the other is used to test connectivity between the NRF24 modules.
Short demo video HERE.