Water Tank Full & Low Level Alarm Circuit With Momentary Switch To Turn Off The Alarm
Author: Manikandan K J
This circuit produces an audible alarm when the water level in a rain or water tank rises above a preset level and overflows. It will sound an alarm whenever the water level reaches the top position in the overhead tank, thus it alerts one to turn off the motor to prevent water wastage.
The purpose of this circuit is to detect when there is an overflow of water in a tank and stop it from continuing to rise which would cause flooding. This can be useful in many different places where there are tanks of water like swimming pools, fountains or overhead tanks for example.
It has a power indicator and a full tank led indicator apart from the alarm. The power to this device can be kept "on" all the time (24 X 7). We can turn off the alarm sound by pressing the momentary switch. We can use contact type sensors or float switches to sense the water level inside the tank. We can use this circuit in the overhead tank, swimming pools, underground sump, aquariums, etc.. in order to monitor the top or low level.
When setting up this overflow alarm circuit, it is important to ensure that you have a 9 or 12v step-down transformer with a current rating ranging from 200mA to 500mA. We can also power this circuit using a 12V SMPS power supply. Using speaker wire, you can easily connect the device to the sensor or float switches inside the tank. For the alarm, a continuous tone buzzer has been used, but you also have the option to use a musical buzzer or a recordable chip with a slight modification in the circuit. This will allow you to customize the alarm to your preference.
Circuit Diagram
Parts Required
DB1 - W04 or Db107 (Bridge Rectifier)
9V to 18V AC - Step Down Transformer, 200 to 500mA
Capacitor:
C1 - 220uf / 40V
C2 - 0.001uF (ceramic or polyester) - 102
Diode:
IN4007
Resistor: (All 1/4W)
R1, R5 - 4.7K
R2, R3 - 470K
R4, R6 - 2.2K
R7 - 22K
R8 - 33K
Transistor:
Q1, Q2 - BC547
Buz - 3v to 24V DC buzzer (continuous or intermittent)
Led - 3mm 0r 5mm
L1 - Green
L2 - Red
S1 - Normally Open Momentary Switch
Sensor - Contact type metal sensor or float switch or stainless steel spoon:)
Integrated Circuit:
U1 - 7812 (Used when a 12v or a higher voltage transformer is used)
U2 - 555 Timer IC
A fully finished product is available at kjmindia.in
Readymade Kit
Versatile in its functionality, this single circuit can serve as an overflow alarm, low tank alarm, and water flow sensor with a simple adjustment to the sensor used. Whether you need to monitor water levels to prevent overflow or to be alerted when the tank is running low, this circuit has you covered. By making a slight modification to the sensor, you can also use it to track water flow, making it a valuable tool for various applications. With this circuit, you can easily customize it to meet your specific needs and ensure efficient water management.
Prototype
