Water Tank Overflow Alarm With Momentary Switch To Turn Off The Alarm and with power and full tank Led indicator.
The simple circuit given here sounds 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. 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 overhead tank, swimming pools, underground sump, aquariums, etc.. to monitor the top level.
If you are looking for a semi-automatic controller circuit, click here or a simple automatic water level controller circuit,click here. This circuit can be powered by a 9 or 12v step-down transformer of current rating ranging from 200mA to 500mA. We can use speaker wire to connect the device to the sensor or float switches inside the tank. For alarm, here I have used a continuous tone buzzer. We can also use musical buzzer or a recordable chip with a slight modification in the circuit.
This circuit can be assembled easily on a general purpose Pcb.
DB1 - Db107 (Bridge Rectifier)
9V AC - Step Down Transformer, 200 to 500mA(12V can also be used)
C1 - 47uf Capacitor
Resistor: (All 1/4W)
R1 - 4.7K
R2 - 4.7K
R3 - 100K
R4 - 8.2K
R5 - 1K
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
U1 - 555 timer ic
Fully finished product is available at kjmindia.in