Build Your Own Automatic Aquarium Top-Off System with Arduino Uno & HC-SR04

Every part needed, pre-tested for compatibility, with an AI build companion trained on this exact project. Shipped from Bengaluru in 3-5 days.

Water evaporation can silently drop your aquarium level, stressing fish and plants. This kit lets you build a smart sensor system that monitors the water surface with an ultrasonic module and activates a pump to refill only when needed. In just a couple of hours, you'll have a working automatic top-off proven to keep your tank stable without manual checking.

What You'll Build

A fully functional water top-off unit that uses an HC-SR04 to measure the distance to the water surface. When the reading falls below your set threshold, the Arduino Uno triggers a relay that switches on a submersible pump, adding water through the silicone tube. It stops automatically once the safe level is restored—perfect for freshwater aquariums, planted tanks, or classroom hydroponic demonstrations.

What You'll Learn

• How to interface an HC-SR04 ultrasonic sensor with Arduino and avoid false readings
• Writing Arduino code to compare real-time distance and control a relay module
• Safe wiring of a submersible pump using a relay and flyback diode protection
• Calibrating water level thresholds for reliable automation and real-world sensor logic

Kit Contents