Fluid
level indication is very necessary to let us know when to refill or stop the
filling to prevent over flow and waste of material. Here we shall make/design a
very simple water level indicator with basic electronic components.
There
are many articles and videos on internet, which show how to make one but they
mostly, use transistors for switching. Just coping and making it is very easy
but what if we have to designing it, then it will be a problem to new comers
(beginners).
Like
finding Gain, Max. Collector current, required collector current, required base
current, and base resistance required for the specified base current and many
other things.
So
let us get rid of all these and design a simple and Easy Circuit that
will indicate water level.
Here
you need a basic knowledge about LEDs and resistors, and if you do not, there
is no need to worry about I shall teach you.
Let’s have a look on our circuit first. All we need is to complete the circuit for the specific indicating LED. Water is a conductor so in this case we don’t have any problem. Connect anode of all LEDs through current limiting resistors to the anode of battery. Place the cathode of battery in the bottom of tank and put LED's cathodes at different levels in the tank. As we know water is a conductor, so as the level of water rises battery cathode will get shorted with led's cathodes, indicating the level where water has reached. In the similar way all three LEDs will be lit.
Now grab your favorite three different color LEDs and select each color for specific level indication (in my case I chose Red for Full, Green for half and Yellow for low level indication).
Here
are there required Forward Voltage and Current drawn by LEDs in following table:
(Refer to Data Sheet for your LEDs)
LED
Color
|
Voltage
(V)
|
Current
(mA)
|
Red
|
2
|
20
|
Yellow
|
3
|
30
|
Green
|
3
|
30
|
Now
calculate the current limiting resistor values for each LED using the following
formula.
Repeat this process for each LED and you are ready to implement the circuit.
Prepare a PCB (if you don’t know then let me know I shall show you) or use Vero Board.Place the components according to the given diagram and solder them.
Connect
to the Battery and Feel Happy that you have learnt to design a new circuit.
Till
than stay happy and keep learning.
If
I made any mistake during the process or you think you can design better than
this one so please let all of us know because knowledge is not confined to some
specific person every one is creative but in their own way.