Automatic turn off water pump on desired level + water level indicator/sensor
PART NO. 2215988
This kit is used to learn how we can use simple cmos 4049 inverter to create latch circuit for turning ON and OFF water pump, sensor
and indicator. Also this device uses two different voltage levels for his work. Firstly we use linear regulator to step down 12V DC to 9V
DC, that voltage level is used as supply for IC 4049 and LEDs. Second voltage level is 5V and it is obtained with second linear regulator
which will step down 9V from first regulator to 5V, those 5V are used as supply for relay module. This two levels are needed because
cmos 4049 for his work needs voltage in range from 5V to 16V.
This project is designed around single CMOS Logic Inverting 4049 chip, water pump is turned ON and OFF with relay module whi le
water level in tank is shown with 4 LEDs.
Firstly as sensors for this circuit simple copper wires which are placed on different levels in tank could be used, ground wire is placed
at the bottom of tank.
Inputs of logic NOT gates are connected in series with resistors of big value and with positive terminal of power supply, sensor wire is
connected between resistor and NOT gate input.
Output of inverting gate is connected with LED and appropriate resistor. So if we put positive voltage on input of NOT gate we will get
negative output so LED diode will not glow.
When water in tank starts to rise it will get in contact with sensor and will ground input of NOT gate and that means that output of NOT
gate will change from negative to positive and LED will glow and indicate water level. LED diode and resistor are connected with ground.
Those positive outputs are also used to feed transistor base which then brake latch circuit and turn OFF water pump.
Latch circuit is created with two NOT gates in series and resistor in parallel with them.
Latch is turned ON by getting positive impulse on input of first NOT gate and that positive impulse at the output of second NOT gate will
activate transistor which will then activate relay module and water pump.
Latch will be broken by grounding inputs of NOT gates with transistor which will be turned on like LED diodes.
