Measuring quantity in a container

[Harini Krishna]

Hi,
We want to measure the quantity in the steel container placed on ABS plastic body. We are planning to go with flexible pressure sensor placed as shown in figure.
But i doubt if it would measure the correct quantity?
Can you suggest on how to place the pressure sensor so that the sensor measurements are accurate( we cannot place it above the plastic body due to application constrains).

Thankyou

 

[quark]

The question is not clear. What quantity do you want to measure? Is it weight or volume? Why indirect measurement?

 

[Harini Krishna]

We want to measure the weight.
We are going for indirect measurement because we don't want to expose electronics on the product.

 

[quark]

Are you filling something in the SS container or you want to weigh container itself?

 

[Harini Krishna]

We have filling in the ss container.

 

[IRstuff]

Why not just weight it normally with a scale? You're going to get garbage because you've got no way to accurately calibrate.

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[Harini Krishna]

We are trying to build a smart lunch box which can measure the amount of food in the ss container.

 

[quark]

Weight by pressure measurement is OK for liquids with direct contact. I am not sure how flexible is your ABS base to exactly convey the pressure and then how the system takes care of density changes in the fill. Better to go with load cells. Again the problem of how exactly the ABS base can convey the actual loads. If you explain the full process then you may get ideas.

 

[IRstuff]

What level of accuracy? Is this for school?

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[Harini Krishna]

IRstuff,
The accuracy is +/- 40gms.
The range of measurement is 60gms to 1200gms
THIS IS NOT FOR "SCHOOL"

 

[IRstuff]

I suggest

https://www.youtube.com/watch?v=iywsJB-T-mU

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[Harini Krishna]

Quark,
we planned going with the load cells but they are too bulky for our application
ABS virgin grade is 2.5mm thick.
Density changes are taken care by defining the range 60gms to 1200gms.

 

[Harini Krishna]

IRstuff,
the application in the video uses load cells,and load cells are too bulky for our application so is the reason we chose flexible pressure sensors

 

[Harini Krishna]

is there any way to measure calories also?

 

[IRstuff]

Sure, you burn stuff

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[Harini Krishna]

IRstuff,
Burning is not suitable for our application.
Can you suggest any cost effective device or method which can measure calories for the application

 

[IRstuff]

You can find approaches on the web; it's a pretty standard high school physics experiment.

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[Harini Krishna]

i made a mistake in my previous post.
burning is not suitable for our application.

 

[quark]

OK, let me hit this straight. Your requirements are unique and the methods you are considering are neither standard nor specific ones. They are beyond that. So far, the replies you got are with standard courtesy this forum maintains.

Without understanding your exact process and what you want to accomplish, the help you get will be minimal. For example, why do you want to check weight in the container? Why you want to weigh the container with in enclosure and why can't it be done outside? What is the relevance of temperature measurement and calorific values (or calories) etc. May be there is other way of controlling your process or may be not.

 

[Harini Krishna]

Quark,
we are trying to implement a lunchbox which would measure the weight of the content in food container to calculate the calories in the food.
to calculate calories in the food, we need the calories of the food present in the box and also the amount of food in the box. So, we can give the total amount of calories in the food contained in the box.