You are right. You can provide a POT at A/D input of MC to correct the variations (It is not essential). But for project purpose/indoor purpose it is possible.
I am sure it will work because I have some experience with this project (in my project i were used thermistors).
Ref. this link **broken link removed**
The above link explains hot water level indicator. It is also possible with normal room temp. water. As i mentioned above you can use a port to change the reference resistance value.
the link you given is only useful for hot water, for normal water it is not useful , and in day time the water may get a little warm that effect the reading.
the best method is to check the water pressure and the simple method is using test leads
Hi,
How about this? I used this method once with a PIC16F84A(yes, when I was starting to learn programming) to sense the level of water in a container(small one) just after it rained.
The lines marked "-" are made of conducting material. You can use tin plates or something similar and there can be as many as you want.
Each of these will connect to an NPN transistor. So that whenever water reaches a specific level, that many transistors will be turned on and each of these will pull the input pins of the microcontroller low and then you can use the microcontroller to sense the level.
The battery positive is stuck to the bottom of the conductor. Beware! The container can not be made of conducting material.
Hope that it helped and that you understood.
Tahmid.
Try putting two parallel insulated wires into the tank and measure the capacitance between them. The value will jump dramatically as water reaches them and will then change proportionately to the water depth.