fake "body fat" scales from Jaycar

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Somebody is perpetrating a fraud on consumers here.

I ordered a set of those "body fat" weight-scales from Jaycar.
The idea is that by passing a small high-frequency current through
the body, you can measure fat/water proportion, and compensate
for hydration level.
    But the readings looked wrong. So I drank a lot of water, and found
the "% body fat" reading went up, not down!   More tests confirmed that
the fat reading is based solely on weight, and the age/height/sex data
that you enter. The electric fat reading is faked.

This is the old-model "satrue sbf-2003a". Is the new one any different?
http://www.jaycar.com.au/productView.asp?ID=QM7249

The website is carefully-worded, but the packaging clearly claims that
it electrically measures fat.

    I suppose Jaycar will refund it, but this makes me mad. Maybe they
will be shocked at my news, and initiate a product recall. Yeah, pigs
might fly - or am I too cynical? Advice please?

(BTW, it was a dumb impulse buy. I should just measure my waistline.
Am trying to reverse the middle-age spread.)

Re: fake "body fat" scales from Jaycar


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Can you actually put a scope on the conductive feet strips and see
anything?

The Jaycar wording is:
[quote]
"Do you know how much excess body fat you are carrying, or are you one
of the lucky few who are within healthy limits. Find out with our 'Body
Fat Scales'. Ordinary scales can only measure body weight, they can't
give you any indication of the amount of body fat you are actually
carrying, and it's body fat that counts. These scales can be calibrated
for use by 8 different  people and requires just their height & sex to
be entered & stored. The scales can also calculate your body fat
percentage if all the relevant data is entered."
[/quote]

This clearly says that body fat can be *calculated* if you enter the
relative data. Nothing about measurement at all.
Although if it's on the box then that's a different story.

If there ain't no signal coming out the feet strips, take it back.
Or just take it back anyway! :->

The professional models are quite good and are based on lots of
research, but all these cheap ones that have flooded that market in the
last couple of years are little more than toys.

Dave :)


Re: fake "body fat" scales from Jaycar




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But not by what... ;-)



Re: fake "body fat" scales from Jaycar


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It will give an error if you wear shoes, so it does something.

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yes, and yes. The website is careful, so I assume jaycar knows,
but they havn't changed the packaging.

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Oh I am. I might try the $90 model, and exchange if its any good.
I'll watch out for the fake consistency that Ross mentioned too.
e.g. weigh myself, pick up a known weight, and try again.

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The thing with this one is that is actively deceptive. And they appear
to know it. Its cheaper to give a few refunds, than to change the labels
and manuals, I guess.



Re: fake "body fat" scales from Jaycar


@quokka.wn.com.au:
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 Now that's just out and out cynical. You bought junk from a
business that is widely known for buying up cheap junk and selling
it at entertainment prices for entertainment porpoises. To go all
"I know my rights" up on their corporate arse is just being silly.
You bought a toy: You paid a toy price. You got a toy. Why is it
that you're so surprised that you didn't get a precision instrument?

GB

Re: fake "body fat" scales from Jaycar



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I guess I'm learning. So jaycar are like "Red Dot" or Oakley Electronics?

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I'm not at all surprised at the poor precision. Its about +/- 400g for
weight.  If it came anywhere near that for fat%, I'd be happy. The claim
is 0.5% precision. Readout is to the 1/10%.

Re: fake "body fat" scales from Jaycar


@quokka.wn.com.au:
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 Jaycar are like "The Reject Shop" or "Everything's $2". A
substantial (and growing) portion of their business involves
buying up whatever is (1) vaguely electronics related and (2)
cheap from distress sales, dodgy importers, etc and on selling
it to their retail customers. That portion of the business
has a constantly rotating stock that, once sold, you'll probably
not see again. They've probably got a container load of these
scales to shift, and when they're gone, they're gone. (Of course,
I think the exception to the rule is in the 'Aura Interactor'
audio/physical feedback things. I think they got a whole boat-
load of those, they've been pushing them for years!)


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 500g is standard tolerance for entry level electronic scales
of this type, so that's about right. I think it's gotta be
substantially more difficult to get a repeatable reading on
the skin resistance thing though - there's so much that will
affect that day to day.

G

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I love those Aura Interactor things! We extract the shaker mechanism
and use it in all sorts of custom built vibration test equipment for
geophysical gear. Very useful!

Dave :)


Re: fake "body fat" scales from Jaycar


snipped-for-privacy@sonicresearch.mailme.org says...
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8<
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Terminology correction: Ship-load :)



Re: fake "body fat" scales from Jaycar



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So it won't work with an open circuit.

Has anyone with one tried:

1a. soaking your feet in a saltwater solution before jumping onto the scales
(resistance)
1b. using the scales before and after jogging (resistance)
2. putting a thin bit of rubber between your feet and the scales
(capacitance)
3. tried to simulate the above with resistors and capacitors of various
values

Peter



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Like the electronic scales I bought from ebay.

I thought they were really accurate for a while because if one got off and
on a few times the scales still came up with the same mass i.e. 76.8kg
76.8kg 76.8kg etc etc until I discovered it just stored the previous reading
in memory and if the next reading was within 0.5 kg the scales would simply
display the previous reading.

Ross



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Same with the jaycars scales, the reading would float around but then at the
very last moment always land on the exact same reading. To get an accurate
reading you have to pick something up that weighs over 500grams to reset it.

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Re: fake "body fat" scales from Jaycar


On Thu, 9 Feb 2006 15:49:48 +1000, "Ross Marchant"

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If you want a decent set of personal scales, the buy the AND uc321

http://www.andmercury.com.au/scales/uc321.htm

Cause they can be calibrated and do show real weight. BE prepared to
spen $300 AU dollars plus though. IF you dont want to spend that
money, then dont complain.

Re: fake "body fat" scales from Jaycar



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Sure the accurate ones need calibration, and are expensive.
Most people just want bathroom scales that are reasonably
*consistent*, and thats much easier.

So I should have been suspicious of the $50 price tag?
The same day I ordered a DVD-player with MPEG-4 for the
same price, and it works fine. It is much more complex
than a set of scales, and includes components of considerably
higher precision. All from China, of course.

Re: fake "body fat" scales from Jaycar


On Fri, 10 Feb 2006 14:09:21 +0800, Mike

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When you can find me a reasonably well machined, accurate cheap
chinese set of load cells please let me know. When you can also find
me some decent load cell amps for the same price please let me know.

The cheapest i ever found when in the market was from korea.

Re: fake "body fat" scales from Jaycar


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 No no! You get to choose any two, not all three!

GB

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Is it possible this is a limitation of the methid being used? Maybe the
water needs to be distributed throughout the body?



Re: fake "body fat" scales from Jaycar



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I thought of that, but we did plenty of other tests. All show perfect
correlation
between mass and %fat reading. But it takes several seconds to "measure"
  _after_ the weight is given.
    It has plausible deniabilty though. No doubt the execs in Taipei
would blame the engineers in China.

Re: fake "body fat" scales from Jaycar


@quokka.wn.com.au:
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 I'm not so sure that you've been dudded you know. You paid fifty
dollars, and got fifty dollars worth of equipment. Chances are,
the guys who designed it were given a price tag to work to. Knowing
that one cannot do a *repeatably reliable* measurment for that
amount of money, they wrote in a damper that won't allow it to
feed you readings that vary from day to day by too much more than
an average punter will *actually* vary from day to day.

 You'd likely be equally upset if you'd gotten a machine that *did*
do a raw calculation every day, but did so with a tolerance of
+/- 30%. At least this way you're getting some degree of consistency
in the readings, even if it takes several days to average out at
an 'accurate' figure.

 I think it is fair to suggest that money buys tolerance. The more
money you spend on an instrument, the more accurate it is likely
to be. It is arguable that by virtue of the 'damper' arrangement,
you got a better instrument than you paid for.

 Food for thought, if nothing else.

GB

Re: fake "body fat" scales from Jaycar


On Thu, 09 Feb 2006 09:57:25 +0800, Mike

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Fuck man, if you are fat, its going to be pretty visible. You dont
need a toy to tell you. I suggest only a fat fuck will complain. I am
getting kinda fat these days, but i dont need any toy to tell me. Get
a life you dickhead, if you are stupid enough to beleive it then you
deserve to be ripped off.

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