Water Level Indicator and Controller

Water Level Indicator and Controller


INTRODUCTION:

This project is very much different from other water level indicators, many water level indicators are available in the market, they are cost efficient & reliable also, but the main disadvantage of this type of W.L.I is that the readings are observed by going close to the tank. This is because each LED is connected to the wire which senses the level. Now if 8 level indicators are used then the no. of wire used is 8, so the LED indicator is placed very close to the tank. If you want to observe the output at some distance place you should extend all the 8 wires connected to the LED’s, which is hectic & costly job. To overcome the above disadvantages instead of using analog IC’s we use two Microcontrollers. The 1st one is programmed to sense the level & transmit the level data serially, the 2nd one is programmed to receive the serial level data & show the level position on port 1 connected to the LED indicator.

WORKING OF THE CIRCUIT:

Like in remote operations two units are required; this project is also uses two units. The working of the circuit is basically divided into two parts. The 1st part is the transmitter & the 2nd part is the receiver, we will explain both the parts one by one.


TRANSMITTER:

In the above circuit the IC used is a 20 pin uC AT89C2051 form Atmel 8051 family, it is programmed in such a way to receive the data from port 1 & send it serially on port pin 3 (TXd). The port pins are connected with 8 PNP BC557 transistors, these transistors are used as a switch in this operation. The collector of the transistor is connected to the GND, emitter pin is connected to the p1.0 through p1.7 & the base is connected to the metallic strips which are pored in the water tank, there are 9 metallic strips. 8 for the level indication & remaining 1 is connected to the GND. The shortest strip is connected to the T0 & the 2nd last longest strip is connected to the T7, like wise all the strips from shortest to the 2nd last longest are connected serially through T0 through T7 as shown in the figure above. Now when we switch on the supply & the water level in the tank starts rising 1st the 8th & the 9th pin comes in contact, this makes transistor T7 to conduct which in turn puts a ‘0’ on the p1.7. Now this data is transmitted serially on TXd pin of the uC. The water level again rises & the 7th strip also comes in contact with the water, in this case T7 & T6 both are in on state which in turn apply ‘0’ to both p1.7 & p1.6. Now this data is also transmitted serially on TXd pin of the uC.

In this way as the water level rises up to the strip connected to T0, different data for each rise in level is transmitted on the serial port. In this way the transmitter works.

RECEIVER:


In the above circuit the IC used is a 20 pin uC AT89C2051 form Atmel 8051 family, it is programmed in such a way to receive the data serially from RXd pin no. 2 & send it on the port p1, it is the receiver part of the circuit. The port pins p1.0 through p1.7 are connected to 8 LED,s which indicates the level of water in the tank, this data is received serially.

ADVANTAGES:

The main advantage of this circuit over the others is that it can send the sensed level of water on to certain distance say up to 100m by using two wires only. In other indicator a 8 bit data line must be required to send the sensed level of water through a distance which is costly enough.