It’s pretty common these days for kitchens to have an auxiliary tap water line installed. That is mostly intended to be connected to your refrigerator to feed the ice maker and water dispenser. Some people also connect that or an additional line to a coffee maker so the water reservoir doesn’t have to be filled manually. But if your refrigerator is a more basic model and you don’t have a coffee maker, that water line is probably going unused. To take advantage their unused water line, Redditor StorageB107 built an ESP8266-controlled water dispenser that is hidden tidily under the upper kitchen cabinets.
This project is perfect for anyone who has a spare water line in their kitchen or wants to add one in order to partake in the convenience of automatically dispensed water. Those water lines are generally connected to the same pipe that goes to the kitchen faucet and so they just provide regular old tap water, but you can use any standard under sink water filtration system if tap water icks you out. The water line runs to the custom-built dispenser device that StorageB107 designed themselves. That does require power, so it needs to be close to an electrical outlet or at least a mains wire. Obviously, make sure you know what you’re doing if you are adding a junction to a mains line.
The water line will have pressure, just like your kitchen faucet. That means that a pump isn’t required for the dispenser device. An electronically-controlled water valve is all that is needed to allow the water to be dispensed. That is controlled by a NodeMCU ESP8266 board through a MOSFET transistor, which directs power from the 12V power supply. That 12V is pushed down to 5V for the NodeMCU by a buck converter. A pair of infrared sensors are used to detect the presence of a glass beneath the dispenser, which opens the valve. Adafruit NeoPixels light up the glass and provide a visual indication that the glass has been detected. The electronic components are all housed within a simple, but attractive, 3D-printed enclosure. StorageB107 has provided that STL file, the schematics, and the code so that you can build your own water dispenser for your kitchen.