Aug 192020
 

Automatic Water Level Controller Circuit

This automatic water level controller circuit ensures that the tank always has a sufficient amount of water. There are many houses or buildings that, due to their geographical location, do not have the necessary water pressure.

In order for the pressure to increase and be able to reach everywhere, it is necessary to place an elevated tank and thus the water is distributed by gravity.

To bring the water from the ground level to the tank, a pump (motor) is used. This pump activates itself whenever the water level is below an already set level and deactivates when it reaches a maximum level, also set.

The tank has 3 sensors that indicate the amount of water in the tank to the controller circuit.

How the automatic water level controller circuit works?

When the water level rises:

1 – When the tank is low or has no water, no sensor touches the liquid or only the lower sensor does. In this case the pump is connected and pumping water to the elevated tank. See that the pump is working (its normal state) when the relay is not active.

In this case, the 555 outputs a high voltage level (approximately 10 to 11 volts) that, after passing through the network of capacitors, diode and resistance, does not saturate the transistors.

Automatic Water Level Controller Circuit

Automatic Water Level Controller Circuit

2 – When the water reaches the level of the second sensor, there is no change and the pump is still active filling the tank.

3 – When the water reaches the level of the third sensor (the upper sensor), the 555 integrated circuit starts its operation as an astable multivibrator. This multivibrator delivers a continuous square wave at its output, which is rectified (half-wave rectification) and applied to the set of two cascaded transistors.

These transistors go into saturation and activate the relay, which in turn disconnects the water pump, ceasing to fill the tank.

555 timer IC Pinout

When the water level drops:

The water level drops when water consumption starts.

1 – When the three sensors are still underwater (tank full), the relay is active and the pump is not connected (it does not pump water into the tank)

2 – When the upper sensor is no longer underwater, the relay is still active and the pump still does not work (it does not pump water into the tank)

3 – When the second sensor is no longer underwater, the relay is deactivated and the pump is switched on (water is pumped into the tank)

Thus, the process of filling and emptying the water is constantly repeated.

List of components of the water tank level controller circuit

  • 1  555 timer (IC1)
  • 1  BC547 or similar NPN bipolar transistor (Q1)
  • 1  2SD882, NTE184 or similar NPN bipolar transistor  (Q2)
  • 1  1N4148 or similar rectifier diode (D1)
  • 1  1N4001 or similar rectifier diode (D2)
  • 1  2 poles, double contact, 12 volts relay (RL), Capable of conducting the current of the water pump.
  • 1  56 ohm resistor (R1)
  • 2  1K resistors (R2, R5)
  • 1  100K resistor (R4)
  • 1  10 ohm resistor (R3)
  • 1  0.1uF (microfarads) capacitor (C1)
  • 1  0.01uF (microfarads) capacitor (C2)
  • 2  4.7uF (microfarads) electrolytic capacitors (C3, C4)

Notes:

  • Water is used as the conductive path for electricity between the sensors, but since little voltage and current are used, it is not dangerous.
  • The sensors can be small, well-polished metal rods connected to the circuit by thin conductors.
  • The circuit is connected to a 12 VDC source, but the voltage can be changed to 9 VDC without problems. If it does, the relay must be replaced by a 9V one.
  •  
  •  
  • 26
  •  
  •  
  •  
  •  
  •  
    26
    Shares
  •  
    26
    Shares
  •  
  •  
  • 26
  •  
  •  
  •  
  •  

 Leave a Reply

(required)

(required)