This document summarizes a 6 LED water level indicator circuit with alarm. The circuit uses a CD4049 hex inverter IC with its outputs connected to LEDs through current limiting resistors. The output of one inverter is connected to the base of a transistor, which powers a 3V-24V buzzer when the water level reaches the top. As water fills the tank and touches probes at different levels, it turns on the LEDs in sequence to indicate the water level.

2. 6LED Water Level Indicator Circuit with Alarm
by Manikandan K J
Here is a simple 6 LED water level indicator which
sounds an alarm whenever the water reaches the top
level. The main component of this circuit is CD4049 which
is a CMOS hex-inverter IC. The outputs of the inverters
are connected to the LED through the current limiting
resistor. The output pin 2 of the inverter is connected to
the base of the transistor via a resistor R13 to limit the
base current. Transistor is used here to power the 3v-24v
AC/DC buzzer whenever the water reaches the top level.
Assume the tank is empty initially. As all the inputs
to the inverters are low through 220 kilo-ohm resistors
(R7-R12), their outputs are high (+ ve) and the LEDs do
not glow. When the water is pumped into the tank, it
starts touching each probe kept at different levels turning
the LEDs “on”.
Circuit Diagram:

3. You will need:
Resistors
680 Ohms,1/4W(R1-R6) - 6 nos.
220 Kilo Ohms, 1/4W(R7-R12) - 6 nos.
470 Ohms, 1/4W (R13) - 1 no.
IC
CD4049 - 1 no.
Transistor
BC557 (PNP) - 1 no.
LED
Any Color (LED1-LED6) - 6 nos.
3v- 24v Buzzer - 1 no.
Miscellaneous
Sensor rods, wires, 12v DC supply/500mA, pcb, etc.

4. 6 LED Water Level Indicator Cum Alarm Kit With Motor Dry Run
Protection
This Kit will sound an alarm when:
1) Water Level in the tank reaches full (Visual indication
is also there)
2) There is no water in the sump/well
3) Motor stops running for any reason
Sounds an alarm even if the water flow into the tank
stops in the middle.
6 Levels of indication:
Indicator for Water flow into the tank
Indicator for Overflow
Indicator for 4 different tank Levels
When the kit is switched "ON",
it will wait for sometime and if there is no flow of water
into the tank,it sounds an alarm

5. For loud sound, it can be connected to a 230V electrical
buzzer via a relay(relay is not included)
What is included in this package?
1) Assembled Kit( as shown in the image)
2) 6 numbers of LEDs
3) 12V buzzer
4) Connection diagram
This kit can be built using any plastic enclosures.
Click here to buy now!
Thank you!