# Help with density measuring device

1. Mar 17, 2015

### stregoi

Hi every one i hope someone can give me an idea how to achieve that. I am working for at school project, where i am trying to build a device that measure density of a multilayer object/enviroment. I am thinking to achieve that by measuring the axial force exerced while pushig the device inside the multilayer object.
But how exactly to do that, and what sensors i have to use - i cant really figure that out.
any one can help ?

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2. Mar 17, 2015

### Simon Bridge

Welcome to PF;
Isn't it part of the project that you are supposed to figure that stuff out?
You should start by being specific about what you want to measure ... do you want an overall density (i.e. total mass divided by total volume?) or do you want to know the density of the layers individually or do you just want something like a layer density (number of layers per unit length) or something else?
The you need to think about how the kind of density you want to measure affects the action you propose to use to measure it ... how do the layers resist the rod pushing through them?

YOu should also be prepared to abandon approaches that don't work well, or where you have too much trouble getting them to work right.

3. Mar 20, 2015

### Baluncore

If you push the pin at a fixed rate while recording the pressure needed to advance you will get a depth profile of resistance to penetration of the material.
What is the layered material?
What is the dimension of the problem, pin diameter? and layer thickness?
Do the layers always increase in “density” with depth, or are some less dense than earlier ones?
What shape is the end of the pin; flat, spherical or pointed?
Will the pin push material on the flat end?
How will you avoid friction between the side of the pin and the material?
Will the layers flow or fold back again after penetration?
Might you be better using a ball on a thinner pin to avoid friction?

4. Mar 30, 2015

### stregoi

Hey guys thanks a lot for the answer, really appreciate it .. i was thinking about my project and i redesignet it, to be more specific ( hopefully making it easy for my self to achieve )
I am trying to monitor, the accelerating of a handdrill, while drilling ( and thus being able to register the slip when the drill go through the other edge of the wood panel ).
I was thinking about using an accelerometer as a sensor to achieve that ? or a pressure sensor ? but is it precise enough to do the job, any idea og suggestion how to achieve that the best way ?.

5. Mar 31, 2015

### Simon Bridge

sounds like something you could do ... but you still suffer from lack of detail: what do you want to achieve? I.e. why not just detect the drill penetration by looking at it, you know, the normal way?