Thanks for the suggestions....I will follow up in the next week and see if either might be a solution to this.


--- On Mon, 3/23/09, Walter Banks <walter@bytecraft.com> wrote:

> From: Walter Banks <walter@bytecraft.com>
> Subject: Re: [EE] resistive force sensing
> To: "Microcontroller discussion list - Public." <piclist@mit.edu>
> Date: Monday, March 23, 2009, 9:21 AM
> An anchored beam with a glue on strain gauge sensor. The
> sensors are very
> low cost and can be read with one of the charge balancing
> circuits
> to at least your requirements.
> 
> http://www.bytecraft.com/Low_Cost%2C_Low_Speed_A_D_conversion_for_Embedded_Systems
> 
> Use Ri as the sensor in the above example. Tie the open end
> to Vcc. It will be slow a few ms to
> read but very low cost
> 
> The output is linear, with two point calibration.
> 
> Regards,
> 
> --
> Walter Banks
> Byte Craft Limited
> http://www.bytecraft.com
> 
> 
> 
> 
> alan smith wrote:
> 
> > Question was brought up, and perhaps someone has an
> answer.
> >
> > The problem to solve is to be able to repeatable and
> reliably measure a weight of a range of 35lbs to 150lbs
> using some sort of flat & flexible surface.  I've
> used load cells before but they are too bulky and expensive.
>  Ideally he wants this to be portable and flexible so some
> sort of resistive network maybe?  The range can also be
> divided up...say 35 to 65, 65 to 95, etc...one model does
> not need to cover the entire range.  Also it does not need
> to be accurate to the pound..can be +/- 2 to 4 pounds.  The
> micro would measure the output of the sensor, and do a
> lookup table or something based on what is coming in.  Its
> more of a go/no go type application.
> >
> > Any thoughts?
> >
> >
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