Water Level Indicator Circuit

One of the most common circuits in the market is the water level indicator. But most of these circuits fault corrosion of metal electrodes due to electrolytic reaction. This fault can be minimized effectively by using alternating current instead of direct current supply. Here we design and verify a circuit called electrolysis proof water level indicator using a COMOS IC which has profitably exploited the normally unused property of CMOS devices.

Other Water level indicators and controller circuits posted on bestengineeringprojects.com 

  1. Ultrasonic Water Level Meter
  2. Water Level Indicator Circuit using 7-Segment
  3. Water Level Controller Using NE555

Description of Electrolysis Proof Water Water Level Indicator Circuit:

The water level indicator circuit is built around a hex inverter buffer CMOS IC. The water level indicator circuit has six level indications because it contains six independent inverter units. When the water levels with the sensor element in output go high making the respective LED ‘ON’. On the further rise in the water level, more LEDs will get switched ‘ON’ in ascending order.

water level indicator circuit

The value of resistance R in the water level indicator circuit is found to be around 12MΩ in the case of tubes of 1.2-meter depth and equally spaced discs as shown in the circuit diagram of the water level indicator. Its value may be changed considerably, depending on the minerals and other chemical contents of water, the spacing between the sensors, the position of the sensors, and their surface area. The value of R can be selected to give the water level indicator circuit any desired sensitivity up to a maximum of about 20 MΩ.

Sensor elements can be inserted in a screw-capped glass tube of 2cm diameter and length equal to the depth of the water tank which is open at the base end. The sensitivity of the water level indicator circuit is relatively independent of the lead length. All seven leads have to be insulated properly to avoid possible short-circuit.

PARTS LIST OF WATER LEVEL INDICATOR CIRCUIT

Resistor (all ¼-watt, ± 5% Carbon)
R1 = 200 KΩ, ½ Watt

R2 = 100 Ω, 1Watt

R3 – R8 = 220 Ω, ½ or ¼ Watt

R9 – R14 = See text

Capacitors
C1 – C6 = 1 µF/25V electrolytic capacitors
Semiconductors
IC1 = CD4049 (CMOS Hex Inverting Buffer/Converter)

ZD1 – ZD2 = 1Z5.1 or equivalent (5.1V, 1W) zener diode

D1 – D6 = DR25 or DR50 diodes

D7 = 1N4001 or equivalent diode

LED1 = LED6 = RED LEDs

Miscellaneous
X1 = 230V to 9V mains transformer, with 200mA secondary

SW1 = 250V AC SPDT Switch

NEON Lamp

Sensor Elements

 

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