Hi folks, today I am going to discuss about water sensor circuit
Water Level Sensor Circuit: when water reaches to
the sensor set level then LED gets switched ON.
Buzzer, also, can be used to give alarm, along with
LED indication.
Material:
1.
General Purpose PCB 2x2 inch.
2.
Resistor: 10K ----------
2 Nos.
3.
Resistor: 15K ----------1 No.
4.
Resistor: 1K ----------1 No.
5.
Transistor: 2222A ---------- 2 Nos.
6.
Capacitor: 22uF/25V ---------- 1 No.
7.
Red LED: 5mm ----------1 No.
8.
Black & Red wire ---------- 1 meter.
9.
9V battery with connector ---------- 1 No.
Tool:
Cutter,
solder wire, soldering iron etc.
How
does it work?
With
the help of sensor, conduction in water is tested and signal is applied to the
base and it is amplified by the transistor.
When
there is no water on sensor terminals, no voltage signal is on the base of Q1,
base of Q1 remains low; it doesn’t conduct.
Base of
Q2 is low, so Q2 doesn’t conduct and LED remains OFF.
It
means water level is lower than the set level.
When
water level reaches to the sensor terminals, there is some low voltage at base
of Q1 and it conducts.
Current
flows through Q1 Collector – Emitter, and voltage appears across R3, this
voltage is applied to the base of Q2, and it also conducts.
When Q3
conduct, current flows through LED and it glows,
If you
put a buzzer in place of LED OR parallel with LED then buzzer also gets switched
ON.
Steps
1-
Mount all the components on the PCB according to the circuit diagram.
2-
Connect the battery with correct polarity.
3- Connect the both terminals of sensor
together to test initially.
4- Put the sensor wire into the water, LED
should glow.
Is it glowing?
Yes?
Great!
So we
have water level sensor now,
Sensor
wire length can be increased according to our need.
The
sensor is nothing but a plastic pipe with two screws over it for water sensing
by current conduction.
NOTE: NEVER
CONNECT THE BATTERY IN WRONG POLARITY SINCE IT IS HAVING AN ELECTROLYTIC
CAPACITOR AND IT MAY BE DAMAGED AND MAY DAMAGE YOU TOO.