Water Level Indicator Circuit

This Water Level Indicator Circuit is a small project to show water level in tank by using 4 LED lights.

Each LED tell how much water is inside the tank.

When water goes up more LED turn ON.

It is easy to make and uses cheap parts.

This circuit is good for saving water and gives an alert when tank is full.

What is Water Level Indicator Circuit:

This is an easy electronic circuit to check water level in tank or container.

It uses 4 LED lights for showing water level.

Circuit have 4 LEDs when put in tank the LEDs blink when water touches them.

When water go up more LEDs start blinking.

Each LED show different level of water.

Circuit Construction:

Parts List:

• Use wire without plastic cover it remove plastic to see metal wire inside.
• Put one common wire at bottom of water tank and be sure it stays below L1 wire.
• Fix wires L1, L2, L3 and L4 at different height in tank.
• Connect each level wire to transistor base: Q1, Q2, Q3, Q4.
• Connect each transistor Q1 to Q4 to one LED.
• Use 9V battery to give power to circuit.

Working Principle:

When we give power to circuit all transistors work like switch.

If no signal connects to base then transistor stay open with no work.

When water level goes up the common wire touches level wires L1 to L4.

Then transistor get signal on base and become closed switch.

LEDs connect to transistor and so they turn ON and show water level have reached.

Formulas:

Formulas for Water Level Indicator Circuit:

1. Base Supply Voltage (Vbase):

Vbase = Ibase × Rbase

• Vbase is voltage between transistor base (B) and emitter (E).
• Ibase is small current which connects into base of transistor.
• Rbase is resistor connects between base and power or ground.

This formula tell how much voltage we need at transistor base and how much current (Ibase) gets depends on value of Rbase.

2. LED Current (ILED):

ILED = (Vbattery − VLED) / RLED

• ILED is current flow in LED in milliamps (mA).
• Vbattery is battery voltage like 9V.
• VLED is voltage drop on LED when it light up which depends on color between 1.8V to 3.3V.
• RLED is resistor in series with LED to control current.

Use this formula to check how much current connects to LED and choose RLED value based on VLED and ILED we want.

Note:

These formulas help to understand how circuit works.

To make circuit work good choose right resistor and parts using above formulas.

Conclusion:

We can make easy and low cost Water Level Indicator using 4 LEDs and by following steps for making and working.

This small circuit helps to save water.

It show water level in tank using LEDs so we stop filling before overflow and no water gets waste at home.

References:

How to Make a Water Level Indicator

Water level indicator LEDs one by one