water pump control circuit design

INTRODUCTION:

Water pump controller  means something , which can control the water pump. That means it can automatically  control the pump/motor. When the water level is low, the controller will automatically switch on the motor  and when water is full in the water tank, it switch off the motor. It is the main objective of my water pump controller circuit.

OBJECTIVES:

—  To make a water pump controller circuit.

—  To design a simple circuit than the market products.

—  To minimize the cost.

—  To make the circuit small & light weight.

—   Increasing efficiency.

WHY WATER PUMP CONTROLLER:

For the supply of water it is very common method to use tank. Generally a person has to manually switch on the water pump when the tank is running low of water. Also when the tank is filled a person has to switch off the water pump manually. This process is inefficient because the person has no idea about the current water level in the tank. Therefore it cannot be known when the water is going to run out and when the tank is filled up, until the actual thing occurs. This may cause unexpected cut off of water supply. Also when the water is being pumped up the person has to wait until water overflows and then switch off the water pump. To improve this to certain extent sensors can be placed in the tank to measure the water level. Then the person can monitor the water level in the tank and can take necessary actions. In this system sensors are used to measure the water level in the tank and the water pumped is automatically switched on and switched off as required. This system minimizes human intervention and eliminates the inefficiencies described above.

Apparatus:

1. DC power supply(6V)

2. AC power supply(220V)

3. Flip flop IC(74279),1 piece

4. NPN Transistor(BC547), 4 pieces

5. Relay(6 volt), 1piece

6. Resistor(10k,10k 4.7k.4.7k), 4 pieces

7 diod(1N4007), 1 piece

8.capacitor(0.1uF)), 1 piece

9. LED, 2 pieces

10. Connecting wire, as required

THEORY:

The working principle series of automatic water pump controller above is, At the time the water level is below both sensors, then the output of flip flop will be one and active relay through the transistor and turn on the water pump. When the water touch the higher level sensor then the relay becomes off. Thus the motor becomes off. When the water does not touch all the sensors the relay becomes on and the water pump will turn on and when all the sensors touches water the relay turns off. Automatic water pump controller can be used to fill or drain the water according to which mode is selected via the relay.

TRUTH TABLE:

INPUT	INPUT	OUTPUT
Set	Reset	Q
1	0	0
1	1	0
0	1	1
1	1	1
0	0	1

SWITCHING ACTION OF TRANSISTOR:

Here I use an n-p-n transistor for switching. The base of the circuit connected with the output of IC. I get output from collector. When the power on then the base-emitter junction is forward bias and when power off then base-emitter junction is reverse bias.

BIASING CIRCUIT:  

 The proper flow of zero signal collector current and the maintenance of proper collector-emitter voltage during the passage of signal is called transistor biasing. Here for transistor performed well we use biasing circuit.

CIRCUIT OPERATION:

In the circuit, we have used 3 transistors (u1, u3, u4) as sensor. The ground level of the tank is connected with the dc voltage source. When the water level doesn’t touch any of the sensors then the transistor u1 remains off. Then the dc voltage comes through the resistor R3 and turns on the transistor u4. Thus the ground becomes connected with the set of RS flip-flop. So the input of set is negative or 0 and there is no voltage at reset. As a result we get voltage or 1 at the output of flip-flop. This voltage goes through the resistor R4 and turns on the transistor u2. So, the relay becomes ON and the ac power supply becomes connected to the motor and turns it on. By increasing when the water level touches the upper sensor then it turns on the transistor u3 and the ground becomes connected with reset of the flip-flop. So input at reset is negative or 0. As a result the output is zero. So, the voltage at the base of u2 is zero and the transistor becomes of. As a result the relay turns off and ac power supply is disconnected with the motor. Thus when the water level again goes below the lower level sensor then the motor will automatically switch on. The capacitor is used to reduce the noise.