Simple 4 LEDs Water Level Indicator Circuit

Water conservation is a priority and technology like electronic can help.

This article teaches how to construct a simple circuit for a water level indicator.

It is far less expensive than purchasing one from a store and by using common parts.

This circuit shows the water level remaining in a tank or barrel using LEDs.

It is an excellent project indicating by when the water will fill up without wasting it.

What is a 4 LEDs Water Level Indicator Circuit:

The water level in a tank or container is monitored using a simple electronic circuit that uses four LEDs as a water level indicator.

Four LEDs make up the circuit which when placed it simply blinks when the water level rises.

As the water level increases more LEDs flash to show it.

Each LED represents a different level.

Circuit Construction:

Parts List:

• Use insulationless wires removing the insulation plastic to expose the conducting core.
• Place the common supply wire at the bottom of the water tank ensuring it is below the L1 wire.
• Position the level wires L1, L2, L3 and L4 at different height levels in the water tank.
• Connect each level wire to a separate transistor base Q1 to Q4.
• Connect transistors Q1 to Q4 to LED indicators.
• Power the circuit with a 9V battery.

Working Principle:

When the circuit is supplied with power all transistors function as switches.

Without a base supply the transistors act as open switches.

As the tank water level rises the common supply wire connects with the level wires L1 to L4.

The corresponding transistor receives a base supply and acts as a closed switch.

LEDs connected to the transistors flashes indicating the respective water level has been reached.

Formulas:

Below are the formulas for Simple 4 LEDs Water Level Indicator Circuit:

Base Supply Voltage Vbase:

The base supply voltage is measured by the resistance Rbase​ and the current flowing through the base Ibase​ of the transistor.

V_base = I_base × R_base

here,

• The voltage that is applied between a transistors base terminal (B) and emitter terminal (E) is known as Vbase or base voltage.
• An example of the current flowing into the transistors base terminal is Ibase (Base Current).
• The base resistor or Rbase is connected between the base terminal of the transistor and biassing voltage source which is often the power supply or ground.

For a particular base voltage Vbase the quantity of base current Ibase that flows is calculated by the value of Rbase.

LED Current ILED​:

The current through the LEDs is measured by the LED forward voltage drop VLED​ and the LED series resistance RLED​.

I_LED = V_battery − V_LED / R_LED

here,

• ILED represents the current flowing through the LED in milliamperes (mA).
• The battery voltage that powers the LED circuit is indicated by the symbol Vbattery.
• The particular voltage drop across a forward biased LED known as a VLED (LED Forward Voltage) allows current to flow through it and generate light.
• By connecting in series with the LED an RLED (LED Series Resistor) limits the amount of current that flows through it.

Based on the VLED, Vbattery and intended LED current ILED the value of RLED is selected.

Different LED colors usually have different forward voltage dips which is generally between 1.8V and 3.3V.

Note:

These calculations gives a more thorough understanding of the water level indicator circuits electrical properties.

For best results resistor values and component specifications are adjusted based on these calculations.

Conclusion:

An effective and low cost Simple 4 LEDs Water Level Indicator Circuit can be designed by following these construction and working steps.

This simple 4 LED water level indicator circuit permits responsible water use and saving by enabling homes to avoid wasteful overflow of water loss.

References:

How to Make a Water Level Indicator

Water level indicator LEDs one by one