28-09-2016, 11:09 AM
1456543224-WaterLevelControllerandIndicatorusing8051Microcontroller.pdf (Size: 791.29 KB / Downloads: 4)
This article explains you how to detect and control the water level in an overhead tank or any
other container. This system monitors the water level of the tank and automatically switches
ON the motor when ever tank is empty. The motor is switched OFF when the overhead tank or
container is FULL. Here the water level of the tank is indicated on LCD (Liquid crystal Display).
Using this system, we can avoid the overflow of the water. We have already seen How water
level indicator circuit works using AVR Microcontroller in the earlier post. But, here we are
designing the circuit which is used to detect and control the water level automatically in
overhead tank using 8051 microcontroller.
In this system water sensing can be done by using a set of 4 wires which are placed at
different levels in tank. DC supply probe is placed at the base of the tank.
Water Level Controller using 8051 Circuit Principle:
This system mainly works on a principle that “water conducts electricity”. The four wires which
are dipped into the tank will indicate the different water levels. Based on the outputs of these
wires, microcontroller displays water level on LCD as well as controls the motor.
Water Level Controller using 8051 Circuit Design:
The main heart of this project is AT89C51 microcontroller. The water level probes are
connected to the P3.0, P3.1, P3.2, and P3.3 through the transistors. Port P2 connected to the
data pins of LCD and control pins RS, RW and EN of LCD are connected to the P1.0, P1.1, and
P1.2 respectively.
Initially when tank is empty, LCD will display the message EMPTY and motor runs
automatically. When water level reaches to quarter level, now LCD displays QUARTER and
still motor runs. For further levels, LCD displays the messages HALF and ¾ FULL.
Algorithm for Water Level Controller Circuit:
First configure the controller pins P3.0, P3.1, P3.2 and P3.3 as inputs and P3.4 as output.
Now initialize the LCD.
Continuously check the water level input pins P3.0, P3.1, P3.2, and P3.3
If all the pins are low then display tank is empty on LCD and make P3.4 pin high to run
the motor automatically.
High pulse on the pin P3.0 indicates quarter level, display the same thing on LCD.
If P3.1 is high then water level is half.
High pulse on P3.2 indicates 3/4 full of the tank.
If P3.3 is high then tank is full, now make P3.4 pin is low to turn off the motor
automatically