Ok, I have realised that I have set my specs waaay to high for this project.
I have simplified it significantly, as I put my typing in gear before my Brain.
I thank everyone for considering this project, and helping in any way possible.
Please consider my new specs, and ignore the original

NEW SPECS:
The cannister is 6 cm high (missing in the attached drawing)
I have a plastic container,(see attached sketch). The only thing missing is its height, which is 6 cm., with a void between the inside and outside of the container (see Illustration).
Is there a way to use capacitance or infared beams to decide when the unit is approximately full and approximately not full. (no measuring anything else)?.
Accuracy and or speed is not important at all, but take into consideration that the liquid inside may be many different materials of varying opacity, including water, which is not 100% optically pure usually.

Someone has suggested the following schematic...will it work?


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Is there a circuit that will TURN ON when the container is full, AND OFF when the container is empty.
I cannot use contacts within the container (which would otherwise make this project easy).
So I would like try to do this by measuring capacitance. I can probably fit a 9v battery into it, or a smaller Lipo battery.
Im looking for a design that doesnt use a microcontroller (ya ya ya...I know)
I know that there are industrial capacitance sensors that could do this, but I dont have a lot of space in the interior.
Thank you in advance for any advice.

I have added a bit more explanation, after thinking about this more.
This can simply be, flask is full, flask is empty, rather than taking into consideration of percentage full and empty

 

Hard to say how reliable a capacitive measurement would be. Why not use a pressure sensor or some such to detect the weight of whatever might be in the box (minus the weight of the box itself of course)?

 

Depends on how much the capacitance changes by, which will be largely determined by the dielectric constant of whatever is filling the void (I'm assuming that it is this void that is getting filled.

Also, in order to measure the capacitance, you need to be able to access both sides of the capacitor (i.e., both the inside and the outside walls).

Can you put a conductive sheet of some kind on both walls? Aluminum foil might work adequately.

 

Depends on how much the capacitance changes by, which will be largely determined by the dielectric constant of whatever is filling the void (I'm assuming that it is this void that is getting filled.

Also, in order to measure the capacitance, you need to be able to access both sides of the capacitor (i.e., both the inside and the outside walls).

Can you put a conductive sheet of some kind on both walls? Aluminum foil might work adequately.

Yes, I can get inside, as the interior and the exterior walls are separatable.

 

I found this posting (If it helps):
https://electronics.stackexchange.c...-building-a-low-cost-contactless-water-sensor

 

Hard to say how reliable a capacitive measurement would be. Why not use a pressure sensor or some such to detect the weight of whatever might be in the box (minus the weight of the box itself of course)?

Doesnt require a whole lot of accuracy

 

Hard to say how reliable a capacitive measurement would be. Why not use a pressure sensor or some such to detect the weight of whatever might be in the box (minus the weight of the box itself of course)?

it will be moving around, and does not require a high degree of accuracy

 

How tall is the container,and what will it be filled with? I'm assuming the internal container will be filled, and not the void between them.

 

 

Im not certain if the schematic I posted is worthwhile, especially since I dont understand it

 

How tall is the container,and what will it be filled with? I'm assuming the internal container will be filled, and not the void between them.

My initial post has a small diagram of the container

 

How about a light beam from one side to the other that is blocked when the container is full?

 

Its one of many ways to measure a small capacitance. Not necessarily one I'd use.

 

How about a light beam from one side to the other that is blocked when the container is full?

would this work with the possibility of the liquid being clear??

 

My initial post has a small diagram of the container

correct

 

My initial post has a small diagram of the container

But doesn't show height

 

ahhhhh...whoops.....6cm sorry

 

and whats it going to be filled with? and always either empty or full?

 

and whats it going to be filled with? and always either empty or full?

It is usually empty, should indicate when it has a liquid in it

 

what liquid and whats the container made from?