Automatic Water Pumping System

Here's a "Automatic Water pumping system" which controls the  water pump motor. The motor gets automatically switched on when water in tank falls below the lower limit . Similarly, its get switched off when the water is filled up( upper level ). This circuit is built with the help of 555 Timer IC Which is best and cheap.   

Material required-:

• PCB Board
• 555 Timer IC
• 1k ohm Resistor x 2
• 220 ohm Resistor x 2
• 2 Pin Screw Terminal
• 5V Relay
• Battery(9v)
• Transistor (BC 547)
• Diode (IN4007)
• Led 

Automatic Water pump Circuit-:

If you guys have seen my previous post of relay module you must somewhat familiar with upper part of the circuit ,in which we just have to trigger the base pin of transistor to turn the relay on .Just like that, Here we are using output pin (3) of 555 IC to trig the base pin .

 

When the water level goes up and touch the pin 6 of 555 IC ,output of Pin 3 goes low(0) which switches off the motor. When the level goes below the low level ,that is pin 2 output of pin 3 goes high 

and motor switches on . This process continues  and now, if you're thinking that how the process works inside 555 IC ,then keep reading .

How 555 Timer IC works?

Above Figure is the pin configuration of the 555 Timer IC .

This is the circuit diagram of 555 IC . There are two comparators C1 and C2 , a SR flip flop, two transistors and one converter (NOT Gate) inside a 555 IC .Lets see how it works , negative side of C1

carries a value of 2/3VCC where VCC is the supply voltage in our case it's 9V so when value of positive side of C1 which is pin 6 goes above 2/3VCC(6V) output of C1 becomes high . and if pin 6 goes low then output of C1 goes low. Similarly , in C2 the positive side of C2 carries a value of 1/3VCC when the pin 2 value goes above 1/3VCC output of C2 goes low and when it's below 1/3 VCC C2 output goes high.

From the above figure you can see the truth table of the circuit . just keep in mind that we don't need the last value of truth table which is invalid . and the output of SR flip flop which is invert of Q further goes through the inverter( NOT Gate ) and give us the output from pin 3. 

Now as you are familiar  with 555 IC and how it works. Lets see how we are using this IC in our circuit . 

So Basically there are three possible ways in which we can use 555 IC the first one  is "Astable Multivibrator Mode" ,Second is "Monostable Multivibrator Mode" and third is "Bistable Multivibrator mode".

In Astable Mode signal switches back and forth without any requirement of trigger.

In Monostable Mode signal switches only when triggered for a short duration of time.

In Bistable Mode signal switches when it's triggered and it will remain in that state (on) until next triggers comes.

In our project ,we are using 555 Timer IC in Bistable mode. So overall now you know that how to use the IC and how to make the circuit let me summarize everything quickly . The positive terminal is at the lowest part of the tank so we can say that water is acting as positive supply (Assuming just to make things clear) so when the water level goes below the Pin 2 and as Pin 6 is low too the output of pin 3 goes high and when water reaches or crosses the pin 2 it still doesn't effect the output of the Pin 3.

When the water reaches at Pin 6 output of pin 3 goes low it will remain low until the water level goes  below  the pin 2 and this process will continue .If you have any doubt you can verify it with the truth table or you can ask me in comment section .

For any queries contact me on  -:tombriddle28@gmail.com

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