Water Tank Full Alarm Circuit using the UM66 IC

Introduction

This project presents a simple and cost-effective Water Tank Full Alarm Circuit using the UM66 melody IC. Designed to alert users when a water tank reaches its maximum level, the circuit helps prevent water overflow and wastage. It operates on a low voltage supply of 3.7V DC, making it suitable for battery-powered applications. The system uses water level sensing probes, and when the water touches these probes, the circuit activates the UM66 IC. This IC plays a melody, which is amplified and output through a speaker, alerting users audibly. This solution is ideal for households and small-scale water tanks, offering a reliable and user-friendly water monitoring system. Its compact design and minimal components make it easy to build and maintain.

Component Details

S.No	Component Name	Value	Quantity
1	UM66 IC	Melody IC	1
2	Transistor	BC547	2
3	Resistor	220Ω	1
4	Variable Resistor	50kΩ (Pot)	1
5	Speaker	8Ω, 0.5W	1
6	Power Supply	3.7V DC	1
7	Probes	Metal Rods	2
8	Connecting Wires	–	As needed
9	Breadboard/PCB	–	1

UM66 Pinout

upload soon…

BC547 Pinout

Circuit Diagram

Working Principle

1. Water Level Detection:

The probes are placed at the full level in the water tank.
When the water touches both probes, it completes the circuit because water conducts electricity (to a small extent).
This allows a small current to flow to the base of Q1 (BC547), turning it ON.

2. Activation of UM66:

When Q1 turns ON, it connects the power supply to pin 2 of UM66, enabling the IC.
The UM66 IC starts playing a melody signal from pin 1.

3. Audio Amplification:

The output from pin 1 goes through a 220Ω resistor (R1) to the base of Q2 (BC547).
Q2 amplifies the signal and drives the speaker, making it sound an alarm.