Simple 4 LEDs Water Level Indicator Circuit

Saving water is important, and electronics can help.

This guide shows you how to build a simple water level indicator circuit yourself.

It uses common parts and is much cheaper than buying one in a store.

This circuit uses LEDs to show you how much water is in something like a tank or barrel.

It is a great way to know when it is time to fill up without wasting water.

What is a 4 LEDs Water Level Indicator Circuit:

A 4 LEDs water level indicator circuit is a simple electronic circuit that can be used to monitor the water level in a tank or container.

The circuit typically consists of four LEDs Light Emitting Diodes that light up sequentially as the water level rises.

Each LED represents a different level, and as the water level increases more LEDs light up to indicate the rising water level.

Circuit Construction:

Parts List:

Below are the circuit construction details:

• Utilize 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 illuminate indicating the respective water level has been reached.

Formulas:

1. Base Supply Voltage Vbase:

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

V_base = I_base × R_base

here,

• Vbase (Base Voltage): is the voltage that is applied between a transistors base terminal B and emitter terminal E.
• The amount of current flowing between the emitter E and collector C is determined by the base voltage.
• Ibase (Base Current): This is an illustration of the current entering the transistors base terminal.
• The transistor is a very efficient current amplifier because even a slight change in the base current may have a big impact on the collector current Ic flowing through it.
• Rbase (Base Resistor): This resistor is attached to the transistors base terminal and biasing voltage source (usually ground or the power supply).

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

2. LED Current ILED​:

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

I_LED = V_battery − V_LED / R_LED

here,

• ILED: This is a milliampere (mA) representation of the current passing through the LED.
• In order to guarantee correct performance and avoid damage, it is essential to regulate this current within the advised range for the particular LED.
• Vbattery: This is an indication of the battery voltage that powers the LED circuit.
• VLED (LED Forward Voltage): A forward biased LEDs distinctive voltage drop across it is what enables it to conduct current and produce light.
• RLED (LED Series Resistor): This resistor limits the amount of current that passes through the LED by being linked in series with it.

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

The forward voltage dips of various LED hues commonly vary (usually between 1.8V and 3.3V).

Note:

These formulas provide a more detailed insight into the electrical characteristics of the water level indicator circuit.

Adjustments to resistor values and component specifications can be made based on these calculations for optimal performance.

Conclusion:

By following these construction and working guidelines, you can assemble an efficient and budget friendly water level indicator circuit.

This simple 4 LEDs water level indicator circuit empowers households to avoid the unnecessary loss of overflow water promoting responsible water usage and conservation.

References

How to Make a Water Level Indicator

Water level indicator LEDs one by one