Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!cs.utexas.edu!sdd.hp.com!hp-sdd!charles
From: charles@hpsdl216.sdd.hp.com (Charles Keith)
Newsgroups: sci.electronics
Subject: Re: Electonic scales question...
Message-ID: <1990Jul13.211144.26529@sdd.hp.com>
Date: 13 Jul 90 21:11:44 GMT
References: <25815@unix.cis.pitt.edu>
Sender: charles@sdd.hp.com (Charles Keith)
Reply-To: charles@hpsdl216.sdd.hp.com (Charles Keith)
Organization: Hewlett Packard, San Diego Division
Lines: 37

In article <25815@unix.cis.pitt.edu>, fmgst@unix.cis.pitt.edu (Filip M Gieszczykiewicz) writes:
questions:
>
> 	of coils with a movable "plunger" that moves depending
> 	on the weight of something. (I presume it's cheaper)
> 
> 	How does it work?
> 
> 	3) There is an adjustment pot for the end-user (on the
> 	fron panel) and another one on the pc board that's not 
> 	accessible so easily, what is it for?
> 
Thousands will tell you that this scale probably uses an lvdt (linear
 variable differential transformer) for sensing the position of the core.
 The springs in the scale make the cores position proportional to weight.

I am following up because I have an interesting story from many years ago
 when these scales first came out.  A friend of mine told me about another
 friend who really liked to drink beer, so much so that he kept a keg
 in his refrigerator at all times.  But he never knew when the darn thing
 was going to run out (keeping track of how much he drunk was out of the
 question).  I suggested that he get one of these scales, move the display
 to a convenient place, move the "on" microswitch to a convenient place,
 and adjust the zero offset pot (the "user accessible" pot mentioned above) and
 the scale would read out directly in pints remaining.  Alternatively, the
 second pot ("span" or "calibration") could be used to make it read out
 glasses of any reasonable size.  Simply push a button, get beer status.

I was told that the "Beer-O-Meter" was a smashing success, a true triumph
 of modern technology, and a winner at any party.  It was accurate down to
 a couple of glasses remaining.  Cheers!
    ->Charles(have you hugged your Beer-O-Meter today?) Keith
-- 
Charles Keith
Hewlett-Packard Co.         UUCP: {hplabs|ucsd|hpfcla}!hp-sdd!charles
16399 W. Bernardo Dr.       Internet: charles%hp-sdd@hplabs.HP.COM
San Diego, CA 92127         Disclaimer: I am not a qualified spokesperson.