Low cost weight sensor ?

Anton Erasmus wrote:

> On Mon, 22 May 2006 13:24:04 -0700, Tim Wescott <tim@seemywebsite.com>
> wrote:
>>What's your volumes, and what's your willingness to build your own?  As 
>>Jim Stewart mentioned there are possibilities, but the only commercially 
>>available weight (or force) sensors that I know of are all stainless 
>>steel devices meant to go into an industrial setting and last forever 
>>while being sprayed with salt water and whacked with hammers.  That's 
>>good for the guy who needs one and doesn't want to spend a lot of 
>>engineering time qualifying the sensor, but not too good for a product.
> 
> 
> My volume is fairly low. Initially prototypes, and then 500 or so per
> year. Rolling my own seems to be the only option. 

  Since this is fan-fold paper being fed into a ticket printer, you could
perforate selected tickets on the edges, and use a single 
opto-interuptor as the reader.  That would be << $20

  You could also encode information of the label types, and even 
languages etc.

  If your company do not want any revenuse stream from the paper, then 
you can give the clients a simple punch, and tell them where to punch if 
they want automatic paper alerts :)

-jg