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Quoted message said:Sneaky scales fudge weights deliberately.
I suspect that many modern, microprocessor -controlled bathroom scales
have programmed in hysteresis to increase user confidence in the
scale's accuracy. The scale remembers fresh measurements, say 166.2#,
and if it next measures same weight +/- a little (within a short time),
say 166.8#, then the scale decides to report the *original* measurement
166.2#. Neat. Sneaky. User believes the scale is highly repeatable.On such a scale, I weigh myself multiple times and get the same reading
(to the 0.2#) each time. 166.2#, 166.2#, 166.2#, 166.2#, ...
Then I weigh something different (myself holding a load), to reset the
memory.
Then I weigh myself again... Now, get something like 166.8#, 166.8#,
166.8#, 166.8#, ... very solid again, but 0.6# different from 1st
series of measurements.I tried 6 models (2 or 3 brands) at a retail store display and find
this "feature" common.
What models/brands? I find it hard to believe that the manufacturers would
do that, because it would require additional programming in the scale, and
most modern scales are quite accurate as is.
FWIW, I have a 4 year old Tanita, accurate to 0.2 lb, and I've tested it
like you suggest on a number of occasions. In all such tests, (weigh in,
weigh-in holding a light weight of some sort, then weigh in again) the scale
returns to within 0.2 lb of the original reading, and usually to the exact
original reading.
If I step off, reset, and step back on (without changing anything), I get
the same reading about 65% of the time. The other 35%, it varies by 0.2
lb - I assume this is when my actual weight is somewhere between the two
reported weights.
Perhaps your test was flawed somehow? Or, maybe you were testing some
crappy scales?
--
GG
http://www.WeightWare.com
Computer-Assisted Weight Management
Quoted message said:
Is it important? Maybe yes in the following scenario -- in some sports
like wrestling, boxing, judo, you have multiple competitors weighing in
at the same time, same scale, with possibly very similar weight. Some
competitors are concerned with as little as 0.25#. In this case it
seems one competitor could inherit the weight measurement of the person
in front of him.In a perfect world, competition weigh-in equipment should be
certified/calibrated. But since the bathroom scale appears so
repeatable, some competitions now use modern, microprocessor
-controlled bathroom scales.Somebody's going to say... "you shouldn't do that". Right, I agree.
But (a) it's happening, because (b) this hysteresis (memory)phenomenon
isn't widely known, I suspect.Anyone care to confirm? Contradict? Repeat the experiment on their
own scale? Comment? In my experiment I didn't bother to determine
what weight difference resets the memory -- 1#? 1.5#?Regards,
John Ruckstuhl