Smart Liquid Dispenser Using Arduino
An RFID-authenticated dispenser that pumps an exact, measured volume of liquid — from 100 to 500 ml — using a flow sensor for closed-loop control.
What this build does
An RFID reader scans user cards to grant access, while an OLED screen and two buttons let you navigate menus to register tags or select a target volume from 100 to 500 millilitres.
Once confirmed, the Arduino triggers a relay to run a mini submersible pump, and a water flow sensor measures the exact volume passing through the tube so the pump shuts off the instant the target is reached.
Parts used in the video
An Arduino board, an RC522 RFID module with cards, an OLED display, two tactile push buttons, a water flow sensor, a 5V single-channel relay module, a 5V mini submersible pump with silicone tubing, and a separate 18650 lithium battery pack to drive the pump without brownouts.
Why it is a good first automation project
It combines user authentication, screen menu navigation, motor control and closed-loop feedback in one circuit. Instead of basic timers that drift with battery voltage, it teaches real closed-loop control using live flow pulses for accurate measurement every time.
Want to build this yourself?
The written guide covers the wiring and the code, and the downloads page has the software and links used in the video.