Water Level Indicator Circuit Project Using IC 555 With Motor Dry Run Alarm

Circuit Diagram

Parts Required

Resistors (All 1/4W)
R1 – R6 – 1M
R7 – R12 – 220K
R13 – R17 – 1K
R18 – 3.3K
R19 – 1M
R20 – 100K (Preset)
R21 – 1K
R22 – 1.5K

Capacitors:
104(0.1uF) – Ceramic Disc – 1 no.
100uF,25V – 1 no.
470uF,40V – 1 no.

IC:
U1- CD4049 (with Base)
U2-555(with Base)

Diodes:
D1 – LED
D2 & D3- IN4148
DB1- W04 (Bridge Rectifier)

Transistor:
S8550 PNP

Relimate Connector:
Sensor – 8 Pin (Male + Female + Wire) [Optional]
Led(-) – 6 pin (Male + Female + Wire) [Optional]

Transformer:
9v ,500 – 1000mA
Please note: If you use 7812(U3), we can use 15v or 18v stepdown transformer

Others:
2 pin Terminal Block Connector
12V DC Buzzer

Features of this circuit

• Lоw Cоѕt
• Low Power Cоnѕumрtіоn
• Less electrolysis
• Easily Sеrvісеаblе
• Built Using Readily Available Cоmроnеntѕ
• Nо Mісrо-соntrоllеrѕ аrе used, so no programming knowledge rеԛuіrеd.
• 6 Lеvеlѕ оf Indication (3,4,5 Lеvеlѕ іѕ аlѕо роѕѕіblе)
• Sоundѕ аn аlаrm when the water rеасhеѕ tор lеvеl
• Sounds аn alarm when thеrе is no flоw оf wаtеr іntо thе tаnk
• Sоundѕ аn alarm when the water flоw ѕtорѕ in thе middle
• Sоundѕ аn аlаrm when there is no water in thе ѕumр/wеll thuѕ protecting the mоtоr.
• Can also indicate water low level if flow feature is not used.

Benefits of a Water level Indicator

• Saves Time
• Saves Power
• Saves Water
• Helps one to monitor the level of water from one place without going near the overhead tank.
• Protects motor from dry run
• This is a simple circuit which indicates the different levels of water in the overhead tank. Apart from indication, it ensures the protection of the motor by sounding an alarm whenever there is no flow of water into the tank.

Working

The circuit comprises of CMOS hex-inverter IC and the famous timer IC. Bridge rectifier (B1) is used to convert AC to DC.

Let us assume that the tank is empty. On switching on the circuit, it will wait for few seconds to sense the flow of water into the tank by the sensor that is fitted on the water inlet pipe.

If there is no flow of water into the tank after few seconds (which is set by adjusting the preset R20), the circuit will sound an alarm indicating that there is no flow of water ( the reason may be: there is no water in the sump/well or the motor is not running.).

If the sensor senses the flow of water, you will not hear the alarm until it reaches the top-level set by you. If the water flow stops in the middle, it will alert you by sounding an alarm.

Timer IC in the circuit is used to perform the above function. When the water in the tank touches each sensor, the concerned LED will light up. When the water reaches the top level, it will sound an alarm alerting us to switch OFF the motor.

D2 And D3 are used to pass only the negative pulses for triggering the timer. R13 to R18 resistors are used to limit the current flowing through the LED. We can use either 9v or 12v, 500mA step down transformer to power the circuit.

F[L] in the sensor can be used as the flow or low-level sensing. Similarly, F[L] in the led (-) can be used to indicate water flow or low level respectively.

After assembling the components on to the circuit board, you can use any plastic container in order to fit this kit. I have used a snack box to fit it. It is readily available in almost all supermarkets.

We can use this circuit in different modes: 1) As overflow indicator alone 2) As overflow and low-level indicator. 3) As 3,4,5,6 level indicator. 4) As water flow alarm etc., A single kit for multiple uses.

Frequently Asked Question (FAQ)

Q: Cаn I dіѕаblе the water flоw indicator fеаturе in thіѕ kіt?

Yеѕ.Juѕt remove thе рrеѕеt frоm thе kіt or Shоrt 1 and 2 (ѕеnѕоr) 

Q: Is it possible to stop the alarm after some time?

Yes. It is possible by using the circuit below.

Q:Can I convert this indicator to a controller?

Yes. With a slight modification, we can convert this indicator to a semi-automatic water level controller.

Auto Cut-off For Overflow Alarm

The circuit shown in the presentation will sound an alarm endlessly until the circuit is switched off. The circuit shown at the top of this page is used to cut off the alarm automatically after a few seconds or minutes. Alarm “ON” time can be set by adjusting the preset 1M. Instead of connecting the buzzer directly to the output, it can be connected via the circuit shown at the top. Connect the positive wire (brown wire) to +P and negative wire to -P (black wire)

Parts Required For Auto Cut-off Alarm

Cарасіtоr:

C1 & C2 – 0.1uF(ceramic)

C3 – 100uF

Resistor:(1/4W) 

R1 – 1M

R2 – 1M(рrеѕеt)

IC – 555 Tіmеr ic

Buzzеr – 12V DC

General purpose PCB

Circuit of a semi-automatic water level controller

This is a semi-automatic water level controller. If you need a fully automatic circuit, please contact me. Remove the buzzer from the water level indicator board and connect the transistor’s collector to this input as shown in the above circuit diagram. Momentary switch S1 is used to start the pump. Once the water reaches the top level or if the water flow stops in the middle, the pump will stop automatically. As it has only a few components, this circuit can be easily assembled on a general-purpose PCB.

Parts Required For Indicator To Semi-Automatic Controller

Resistors(1/4W):

R1 – 1k

R2 – 100k

R3 – 100k

R4 – 1k

Capacitors:

C1 – 0.01uF

C2 – 10uF/25V

Transistor:

8050 NPN Transistor

S1: Momentary Push to on switch

IC : 555 Timer

Relay: 12V, 20A or 30A Based on your requirement

General purpose PCB

Placing the probes

You can use thick stainless steel/aluminium or copper wires as sensors or a float switch. We can also use stainless steel bolt & nut, keys, spoons, etc. as sensors.  As electrolysis is not a big issue for me, I have used thick copper wires. We have to clean the wire once a year to remove the dirt deposited on the wire. Please ensure that the sensors do not touch each other or the sides or bottom of the water tank.

Connection Details Of 6 Led Water Level Indicator

SENSOR

1 – F(L) – Used for water flow sensing

2 – +ve supply – Used for water flow sensing

3 – +ve supply – Kept inside the tank but should not touch the bottom of the tank.

4 – First Level

5 – Second Level

6 – Third Level

7 – Fourth Level

8 – Top Level

Both 1 and 2 are used for water flow sensing in the OHT or low water level sensing inside the sump.

LED- should be connected to the negative terminals of the 6 LEDs.

LED+ should be connected to the positive terminals of the 6 LEDs. All +ve terminals should be shorted together.

Preset should be adjusted for the wait time as per your requirement.

Buzzer should be connected with the correct polarity. Brown wire(+) and black wire (-)

Use 9v,500mA – 1A step-down transformer. We can also use 15v transformer. In this case, we have to use 7812 regulator ic in the U3 slot on the board.

We can use 8 colour flat ribbon wire/Cat-6 wire to connect the sensor in the tank to the indicator unit.

For sensor, we can use thick copper wire/aluminium/steel wires or magnetic float switches.

LED Details:

Green colour LED can be used as power indicator.

Red can be used to indicate top level

Tricolour LED can be used to indicate the water flow

White colour LED can be used to indicate other levels.

Working Video