Water Level Indicator for Overhead Tank

Problem statement

In many homes water overflows from overhead tanks because there is no simple indication of tank level during pumping.

Abstract

This project uses a set of conducting probes placed at different heights in an overhead tank to sense the water level. The probes are connected to a simple transistor or microcontroller circuit that lights LEDs to show LOW, MEDIUM and FULL levels. A buzzer alerts the user when the tank is full so that the pump can be turned OFF.

Components required

• Metal probe wires / screws for level sensing
• Resistors and transistors
• LED indicators for each level
• Buzzer
• Power supply
• Optional microcontroller for display
• Connecting cables to tank

Block diagram

Working

Each probe pair completes a circuit when water reaches that height, pulling the associated input line HIGH. The interface circuit decodes which probes are active and lights LEDs for 25%, 50%, 75% and 100% levels. When the top probe is reached, a buzzer is activated. The design can be built with simple transistors or a low-cost microcontroller.

Applications

• Home and hostel water tank monitoring
• Motor room indicator panels
• Community water tanks
• Entry-level analog/digital interfacing project