Tank Full Alarm

Tank Full Alarm

Summary
The circuit describe hear start ringing as soon as the water tank become full hence it help you to check overflow and wastage of water by warning the user  when the tank is about to full as many times it happen we forget to off the motor.
Description
Circuit is based on LM324 which is 14 pin IC consisting of 4 independent operational amplifier in a single package. The output voltage of LM324 is many times higher than the voltage difference between the input terminals of an opamp. This circuit work on very simple concept, But by using this circuit you can prevent overflowing your water tank. After water touching sensors the circuit will give a sound then you can switch off the motor.

The circuit comprises a sensor part built using only one op-amp (N1) of quad op-amp IC LM324. Op-amp N1 is configured here as a comparator. Two stiff copper wires are inserted in the tank containing water. As long as the tank is empty copper wire does not conduct and the circuit remains off.

When the tank dries out, the resistance between the copper wires (sensor probes A and B) increases. As a result output of opamp is high and LED will glow to indicate that tank is empty.
and this will not trigger the IC2. If the resistance increases beyond a preset limit, output pin 1 of op-amp N1 goes ‘low’. This will triggers timer IC2. As a result, LED and buzzer start sounding.
The threshold point at which the output of op-amp N1 goes ‘low’ can be changed with the help of preset VR1.

Components used

IC
IC1(LM324)	1
IC2(CD4011)	1
Resistor
R1-R2(10K)	2
R3(330E)	1
R4(100K)	1
R5(2.2M)	1
R6(180E)	1
VR1(100K)	1
Miscellaneous
Buzzer	1
LED	2