As part of my crusade to clear some of my old junk from the house, I
have been using Freecycle and ebay. For the latter I have been having to
weigh things to post, so I dug out my old Aldi digital parcel scale, and
wanted to check it.
When last used about a year ago, I was stung for extra cash in the post
office because their scales didn't agree with mine.

Fresh batteries and a wipe down with a clean cloth and I was ready to
go, but item weights were all over the place. Reading online made me
head for the hard flat(tish) surface of the bathroom floor where my
1litre of Tesco Pineapple juice repeatedly weighed 1070 grams. Bring it
back to the carpeted "office" floor and I get a variable measurement
with the same juice of around 760grams.
The carpet is thin and well worn, but not threadbare, and I wouldn't
have expected such a difference.

Searches online reveal a number of contradictory explanations and
usually lead to discussions from females stressing about their weight.

Oh, and don't mention Freecycle. My 1U 19" rack case took ages to be
approved by the moderators and has just popped up on page 4 of their new
listings. Who is going to see it there?

--
Bill

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On 01/10/18 18:19, Bill wrote:
As part of my crusade to clear some of my old junk from the house, I
have been using Freecycle and ebay. For the latter I have been having to
weigh things to post, so I dug out my old Aldi digital parcel scale, and
wanted to check it.
When last used about a year ago, I was stung for extra cash in the post
office because their scales didn't agree with mine.

Fresh batteries and a wipe down with a clean cloth and I was ready to
go, but item weights were all over the place. Reading online made me
head for the hard flat(tish) surface of the bathroom floor where my
1litre of Tesco Pineapple juice repeatedly weighed 1070 grams. Bring it
back to the carpeted "office" floor and I get a variable measurement
with the same juice of around 760grams.
The carpet is thin and well worn, but not threadbare, and I wouldn't
have expected such a difference.

Searches online reveal a number of contradictory explanations and
usually lead to discussions from females stressing about their weight.

Oh, and don't mention Freecycle. My 1U 19" rack case took ages to be
approved by the moderators and has just popped up on page 4 of their new
listings. Who is going to see it there?


Why the floor, don't you have a table?

As part of my crusade to clear some of my old junk from the house, I
have been using Freecycle and ebay. For the latter I have been having to
weigh things to post, so I dug out my old Aldi digital parcel scale, and
wanted to check it.
When last used about a year ago, I was stung for extra cash in the post
office because their scales didn't agree with mine.

Fresh batteries and a wipe down with a clean cloth and I was ready to
go, but item weights were all over the place. Reading online made me
head for the hard flat(tish) surface of the bathroom floor where my
1litre of Tesco Pineapple juice repeatedly weighed 1070 grams. Bring it
back to the carpeted "office" floor and I get a variable measurement
with the same juice of around 760grams.
The carpet is thin and well worn, but not threadbare, and I wouldn't
have expected such a difference.

Searches online reveal a number of contradictory explanations and
usually lead to discussions from females stressing about their weight.

Oh, and don't mention Freecycle. My 1U 19" rack case took ages to be
approved by the moderators and has just popped up on page 4 of their new
listings. Who is going to see it there?

You need a hard flat surface!
The carpet is acting like a spring and is sharing the force with the
strain gauges in the scale, that's why you get a lower reading.


--

Graham.
%Profound_observation%

On 01/10/2018 18:19, Bill wrote:

Fresh batteries and a wipe down with a clean cloth and I was ready to
go, but item weights were all over the place. Reading online made me
head for the hard flat(tish) surface of the bathroom floor where my
1litre of Tesco Pineapple juice repeatedly weighed 1070 grams. Bring it
back to the carpeted "office" floor and I get a variable measurement
with the same juice of around 760grams.
The carpet is thin and well worn, but not threadbare, and I wouldn't
have expected such a difference.

In my experience modern light weight scales are only accurate if
positioned on a hard flat surface. Both of the scales in my house are
seated on top of a thick MDF board. As you have discovered a thin
carpet or even vinyl type cushion flooring with a hard foam backing give
inaccurate/inconsistent results.


--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

In message , Richard
writes
On 01/10/18 18:19, Bill wrote:
As part of my crusade to clear some of my old junk from the house, I
have been using Freecycle and ebay. For the latter I have been having
to weigh things to post, so I dug out my old Aldi digital parcel
scale, and wanted to check it.
When last used about a year ago, I was stung for extra cash in the
post office because their scales didn't agree with mine.
Fresh batteries and a wipe down with a clean cloth and I was ready
to go, but item weights were all over the place. Reading online made
me head for the hard flat(tish) surface of the bathroom floor where my
1litre of Tesco Pineapple juice repeatedly weighed 1070 grams. Bring
it back to the carpeted "office" floor and I get a variable
measurement with the same juice of around 760grams.


Why the floor, don't you have a table?

Bad back, and some things are quite heavy. Also, because of family
situation, I'm having to do everything upstairs. My office tables are
somewhere under "stuff". Hence the need to decrappify.
--
Bill

---
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https://www.avg.com

On 01/10/2018 18:38, Graham. wrote:
As part of my crusade to clear some of my old junk from the house, I
have been using Freecycle and ebay. For the latter I have been having to
weigh things to post, so I dug out my old Aldi digital parcel scale, and
wanted to check it.
When last used about a year ago, I was stung for extra cash in the post
office because their scales didn't agree with mine.

Fresh batteries and a wipe down with a clean cloth and I was ready to
go, but item weights were all over the place. Reading online made me
head for the hard flat(tish) surface of the bathroom floor where my
1litre of Tesco Pineapple juice repeatedly weighed 1070 grams. Bring it
back to the carpeted "office" floor and I get a variable measurement
with the same juice of around 760grams.
The carpet is thin and well worn, but not threadbare, and I wouldn't
have expected such a difference.

Searches online reveal a number of contradictory explanations and
usually lead to discussions from females stressing about their weight.

Oh, and don't mention Freecycle. My 1U 19" rack case took ages to be
approved by the moderators and has just popped up on page 4 of their new
listings. Who is going to see it there?

You need a hard flat surface!
The carpet is acting like a spring and is sharing the force with the
strain gauges in the scale, that's why you get a lower reading.

I think it's more likely that the moving part of the scale is pressing
against the pile of the carpet, depending on the design of the scale. I
don't see how putting the scale on top of a springy thing can "share the
force".

--
Max Demian

Max Demian explained on 01/10/2018 :
On 01/10/2018 18:38, Graham. wrote:
As part of my crusade to clear some of my old junk from the house, I
have been using Freecycle and ebay. For the latter I have been having to
weigh things to post, so I dug out my old Aldi digital parcel scale, and
wanted to check it.
When last used about a year ago, I was stung for extra cash in the post
office because their scales didn't agree with mine.

Fresh batteries and a wipe down with a clean cloth and I was ready to
go, but item weights were all over the place. Reading online made me
head for the hard flat(tish) surface of the bathroom floor where my
1litre of Tesco Pineapple juice repeatedly weighed 1070 grams. Bring it
back to the carpeted "office" floor and I get a variable measurement
with the same juice of around 760grams.
The carpet is thin and well worn, but not threadbare, and I wouldn't
have expected such a difference.

Searches online reveal a number of contradictory explanations and
usually lead to discussions from females stressing about their weight.

Oh, and don't mention Freecycle. My 1U 19" rack case took ages to be
approved by the moderators and has just popped up on page 4 of their new
listings. Who is going to see it there?

You need a hard flat surface!
The carpet is acting like a spring and is sharing the force with the
strain gauges in the scale, that's why you get a lower reading.

I think it's more likely that the moving part of the scale is pressing
against the pile of the carpet, depending on the design of the scale. I don't
see how putting the scale on top of a springy thing can "share the force".

+1

I use my bathroom digital scales on a thick bedroom carpet surface,
they are quite predictable, apart from when I step on them off centre.

On 01/10/18 18:19, Bill wrote:
As part of my crusade to clear some of my old junk from the house, I
have been using Freecycle and ebay.

On a related note, I found Freegle to be very good when I used it the
other day. Much updated with som every nice features to make posting
photos and handling enquiries easier. There was a "promise it to X"
option which is nice (it greys it out to let others know someone has
dibs) and a "Release my address". Small things but compared to the last
time I used Freecycle, saved a lot of messaging.

On 01/10/18 18:19, Bill wrote:
As part of my crusade to clear some of my old junk from the house, I
have been using Freecycle and ebay. For the latter I have been having to
weigh things to post, so I dug out my old Aldi digital parcel scale, and
wanted to check it.
When last used about a year ago, I was stung for extra cash in the post
office because their scales didn't agree with mine.

Fresh batteries and a wipe down with a clean cloth and I was ready to
go, but item weights were all over the place. Reading online made me
head for the hard flat(tish) surface of the bathroom floor where my
1litre of Tesco Pineapple juice repeatedly weighed 1070 grams. Bring it
back to the carpeted "office" floor and I get a variable measurement
with the same juice of around 760grams.
The carpet is thin and well worn, but not threadbare, and I wouldn't
have expected such a difference.

Searches online reveal a number of contradictory explanations and
usually lead to discussions from females stressing about their weight.

Oh, and don't mention Freecycle. My 1U 19" rack case took ages to be
approved by the moderators and has just popped up on page 4 of their new
listings. Who is going to see it there?


You might be better with a spring balance (or electronic version
thereof). Avoids a lot of the problems of loads that are off centre and
scales that are fussy about that.

On 01/10/18 18:38, Graham. wrote:

You need a hard flat surface!
The carpet is acting like a spring and is sharing the force with the
strain gauges in the scale, that's why you get a lower reading.

It's not so much sharing forces (unless the carpet is so thick the box
is actually being supported by it) - it's a facet of cheap scales.

The scale box, not being properly supported will twist and the internal
mechanism probably only has one sensor with a lever arrangement and
relies on a solid base and being level to remain accurate.

Even my medical grade Seca scales demand being levelled (and have a
bubble on to assist).

You could construct a set of scales with 3 legs, gauges on each and a
top plate that would in theory be accurate on any surface as long as the
top plate remains clear of any carpet pile.

But no one does that.

"Tim Watts" wrote in message
...
On 01/10/18 18:38, Graham. wrote:

You need a hard flat surface!
The carpet is acting like a spring and is sharing the force with the
strain gauges in the scale, that's why you get a lower reading.

It's not so much sharing forces (unless the carpet is so thick the box is
actually being supported by it) - it's a facet of cheap scales.

The scale box, not being properly supported will twist and the internal
mechanism probably only has one sensor with a lever arrangement and relies
on a solid base and being level to remain accurate.

Even my medical grade Seca scales demand being levelled (and have a bubble
on to assist).

You could construct a set of scales with 3 legs, gauges on each and a top
plate that would in theory be accurate on any surface as long as the top
plate remains clear of any carpet pile.

But no one does that.

There must be a reason why no one does that.

In message , Tim Watts
writes
On 01/10/18 18:38, Graham. wrote:

You need a hard flat surface!
The carpet is acting like a spring and is sharing the force with the
strain gauges in the scale, that's why you get a lower reading.

It's not so much sharing forces (unless the carpet is so thick the box
is actually being supported by it) - it's a facet of cheap scales.

The scale box, not being properly supported will twist and the internal
mechanism probably only has one sensor with a lever arrangement and
relies on a solid base and being level to remain accurate.

Even my medical grade Seca scales demand being levelled (and have a
bubble on to assist).

You could construct a set of scales with 3 legs, gauges on each and a
top plate that would in theory be accurate on any surface as long as
the top plate remains clear of any carpet pile.

But no one does that.

Just to report back, I have now brought in an old, dense square of
wooden flooring tile and put it between the carpet and the scales.

The test reading is now correct, and agrees with the bathroom floor
test.

I am still not totally convinced about the theory behind this. The
carpet has pretty well no pile at all, and the scales have small support
feet that are large enough to keep the bodywork above the pile. I can
push paper between the scales and the carpet.
I'm also not sure about the scales twisting. I can move them between
carpet and smooth surface without reclibrating, and see a reading go
from 0 to 400ish grams with nothing on the scales.

Anyway, I now know how to make sensible measurements. Thanks to all.
--
Bill

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https://www.avg.com

On 02/10/2018 09:56, Andew Jones wrote:

There must be a reason why no one does that.

Very probably someone does but not at a price point to capture much of
the existing domestic market where the accuracy of widely available
products is adequate, if used properly.



--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On Tue, 2 Oct 2018 18:56:16 +1000, Andew Jones, better known as
cantankerous trolling senile geezer Rot Speed, wrote:


You could construct a set of scales with 3 legs, gauges on each and a top
plate that would in theory be accurate on any surface as long as the top
plate remains clear of any carpet pile.

But no one does that.

There must be a reason why no one does that.

You just HAVE to open your senile gob, even if only the most meaningless
**** will come out of it, eh, senile Rot? LOL

--
Sqwertz to Rot Speed:
"This is just a hunch, but I'm betting you're kinda an argumentative
asshole.
MID:

"alan_m" wrote in message
...
On 02/10/2018 09:56, Andew Jones wrote:

There must be a reason why no one does that.

Very probably someone does but not at a price point to capture much of the
existing domestic market where the accuracy of widely available products
is adequate, if used properly.

There is no reason why it costs more and very few
of the domestic products even give a reproducible
reading, let alone an accurate one.

On 02/10/18 09:56, Andew Jones wrote:
But no one does that.

There must be a reason why no one does that.

I was wrong on one count:

It seems, having watched some YT teardown vids, that a lot of cheap
modern scales do have 4 load sensors, one on each foot.

So the problem, apart from how accurate the load sensor is, comes down
to the carpet pile under the very slim base bypassing the sensors and
pressing on say the battery compartment.

All those need, in theory, is longer legs direct to the load sensors and
not coupled to the case on the leg side.

On 02/10/18 10:37, Andew Jones wrote:


"alan_m" wrote in message
...
On 02/10/2018 09:56, Andew Jones wrote:

There must be a reason why no one does that.

Very probably someone does but not at a price point to capture much of
the existing domestic market where the accuracy of widely available
products is adequate, if used properly.

There is no reason why it costs more and very few
of the domestic products even give a reproducible
reading, let alone an accurate one.


The worse thing about cheap bathroom digital scales is that some lie
outright. If you get on and it samples Xkg. Step off, and on and you can
see it read X-5% for a moment then it suddenly snaps to exactly X. You
have to put a dummy lighter load on, or let it turn off and on to get it
to actually take a new reading.

"Tim Watts" wrote in message
...
On 02/10/18 09:56, Andew Jones wrote:
But no one does that.

There must be a reason why no one does that.

I was wrong on one count:

It seems, having watched some YT teardown vids, that a lot of cheap modern
scales do have 4 load sensors, one on each foot.

So the problem, apart from how accurate the load sensor is, comes down to
the carpet pile under the very slim base bypassing the sensors and
pressing on say the battery compartment.

All those need, in theory, is longer legs direct to the load sensors and
not coupled to the case on the leg side.

It can't be that easy or everyone would be doing it.

"Tim Watts" wrote in message
...
On 02/10/18 10:37, Andew Jones wrote:


"alan_m" wrote in message
...
On 02/10/2018 09:56, Andew Jones wrote:

There must be a reason why no one does that.

Very probably someone does but not at a price point to capture much of
the existing domestic market where the accuracy of widely available
products is adequate, if used properly.

There is no reason why it costs more and very few
of the domestic products even give a reproducible
reading, let alone an accurate one.


The worse thing about cheap bathroom digital scales is that some lie
outright. If you get on and it samples Xkg. Step off, and on and you can
see it read X-5% for a moment then it suddenly snaps to exactly X. You
have to put a dummy lighter load on, or let it turn off and on to get it
to actually take a new reading.

Clearly that must be a fudge given how hard it is to get a reproducible
reading, let alone an accurate one.

On 02/10/18 11:00, Andew Jones wrote:


"Tim Watts" wrote in message
...
On 02/10/18 09:56, Andew Jones wrote:
But no one does that.

There must be a reason why no one does that.

I was wrong on one count:

It seems, having watched some YT teardown vids, that a lot of cheap
modern scales do have 4 load sensors, one on each foot.

So the problem, apart from how accurate the load sensor is, comes down
to the carpet pile under the very slim base bypassing the sensors and
pressing on say the battery compartment.

All those need, in theory, is longer legs direct to the load sensors
and not coupled to the case on the leg side.

It can't be that easy or everyone would be doing it.


Not necessarily. It's easy to use conduit for all cables runs in walls
when building a house. Cost: next to sod all extra. No one does it
(well, I did when renovating).

Why? Lazy, cheapskate-ness, "The builder doesn't have to live with
fixing it", etc.

On 02/10/18 11:03, Andew Jones wrote:


"Tim Watts" wrote in message
...
On 02/10/18 10:37, Andew Jones wrote:


"alan_m" wrote in message
...
On 02/10/2018 09:56, Andew Jones wrote:

There must be a reason why no one does that.

Very probably someone does but not at a price point to capture much
of the existing domestic market where the accuracy of widely
available products is adequate, if used properly.

There is no reason why it costs more and very few
of the domestic products even give a reproducible
reading, let alone an accurate one.


The worse thing about cheap bathroom digital scales is that some lie
outright. If you get on and it samples Xkg. Step off, and on and you
can see it read X-5% for a moment then it suddenly snaps to exactly X.
You have to put a dummy lighter load on, or let it turn off and on to
get it to actually take a new reading.

Clearly that must be a fudge given how hard it is to get a reproducible
reading, let alone an accurate one.

It is. It is clearly snapping onto the last reading within a certain
range to give the illusion of repeatability. One of the reasons I went
and bought a decent set - they wibble around +/- 0.1kg as long as I
stand on them with no attempt to freeze the reading.

On Monday, 1 October 2018 18:19:27 UTC+1, Bill wrote:
As part of my crusade to clear some of my old junk from the house, I
have been using Freecycle and ebay. For the latter I have been having to
weigh things to post, so I dug out my old Aldi digital parcel scale, and
wanted to check it.
When last used about a year ago, I was stung for extra cash in the post
office because their scales didn't agree with mine.

Fresh batteries and a wipe down with a clean cloth and I was ready to
go, but item weights were all over the place. Reading online made me
head for the hard flat(tish) surface of the bathroom floor where my
1litre of Tesco Pineapple juice repeatedly weighed 1070 grams. Bring it
back to the carpeted "office" floor and I get a variable measurement
with the same juice of around 760grams.

I check mine with a bag or two of sugar 1KG and always use it on a the hard bathroom floor, never noticed a problem.

I;ve also been weighin a couple of eggs on a small set of scales also always measured on a hard level surface the same surface is a good idea too just in case there's any micro singularities hiding.


The carpet is thin and well worn, but not threadbare, and I wouldn't
have expected such a difference.

Searches online reveal a number of contradictory explanations and
usually lead to discussions from females stressing about their weight.

Well whereever a scale is put it always reads higher than it should, don't argue with them just nod in agreement.

On Tuesday, October 2, 2018 at 1:06:55 PM UTC+1, whisky-dave wrote:
On Monday, 1 October 2018 18:19:27 UTC+1, Bill wrote:
As part of my crusade to clear some of my old junk from the house, I
have been using Freecycle and ebay. For the latter I have been having to
weigh things to post, so I dug out my old Aldi digital parcel scale, and
wanted to check it.
When last used about a year ago, I was stung for extra cash in the post
office because their scales didn't agree with mine.

Fresh batteries and a wipe down with a clean cloth and I was ready to
go, but item weights were all over the place. Reading online made me
head for the hard flat(tish) surface of the bathroom floor where my
1litre of Tesco Pineapple juice repeatedly weighed 1070 grams. Bring it
back to the carpeted "office" floor and I get a variable measurement
with the same juice of around 760grams.

I check mine with a bag or two of sugar 1KG and always use it on a the hard bathroom floor, never noticed a problem.

I;ve also been weighin a couple of eggs on a small set of scales also always measured on a hard level surface the same surface is a good idea too just in case there's any micro singularities hiding.


The carpet is thin and well worn, but not threadbare, and I wouldn't
have expected such a difference.

Searches online reveal a number of contradictory explanations and
usually lead to discussions from females stressing about their weight.

Well whereever a scale is put it always reads higher than it should, don't argue with them just nod in agreement.

I made a small platform with 4 spikes screwed into each corner. They pierce the carpet and alow the scales contact the hard surface underneath

On 02/10/2018 10:37, Andew Jones wrote:


"alan_m" wrote in message
...
On 02/10/2018 09:56, Andew Jones wrote:

There must be a reason why no one does that.

Very probably someone does but not at a price point to capture much of
the existing domestic market where the accuracy of widely available
products is adequate, if used properly.

+1

There is no reason why it costs more and very few
of the domestic products even give a reproducible
reading, let alone an accurate one.

I disagree. My bathroom scales under read by an amount determined by the
carpet thickness but they are extremely consistent about how much.

To make them work on any surface would require much more rigid
engineering of the base plate which adds weight and materials cost.

My kitchen scales which get used on a level rigid surface are accurate
to the claimed precision of 5g on up to 3kg. There is a bit of
hysteresis and stiction on the very low end which means weighting
several identical Xmas cards to work out airmail charges reliably.

--
Regards,
Martin Brown

On 02/10/18 10:51, Tim Watts wrote:
On 02/10/18 09:56, Andew Jones wrote:
But no one does that.

There must be a reason why no one does that.

I was wrong on one count:

It seems, having watched some YT teardown vids, that a lot of cheap
modern scales do have 4 load sensors, one on each foot.

Indeed. Our cheap glass-based scales are at least 12 years old and have
a sensor in each of the four feet.

So the problem, apart from how accurate the load sensor is, comes down
to the carpet pile under the very slim base bypassing the sensors and
pressing on say the battery compartment.

All those need, in theory, is longer legs direct to the load sensors and
not coupled to the case on the leg side.

I have always assumed that each foot has a strain gauge and the output
of each is added to give the final figure. I just tested this by placing
the scales on a triangular-shaped piece of wood which allowed one of the
feet to float in mid-air. No matter which foot floated, the weight shown
was identical to that if all four feet were on the ground. So you are
right; no matter how strange it might seem, it must be the carpet pile
(and underlay) taking the strain away from one or more of the feet to
allow inaccurate and/or variable readings to occur.

--

Jeff

On 02/10/18 13:46, Jeff Layman wrote:
On 02/10/18 10:51, Tim Watts wrote:
On 02/10/18 09:56, Andew Jones wrote:
But no one does that.

There must be a reason why no one does that.

I was wrong on one count:

It seems, having watched some YT teardown vids, that a lot of cheap
modern scales do have 4 load sensors, one on each foot.

Indeed. Our cheap glass-based scales are at least 12 years old and have
a sensor in each of the four feet.

So the problem, apart from how accurate the load sensor is, comes down
to the carpet pile under the very slim base bypassing the sensors and
pressing on say the battery compartment.

All those need, in theory, is longer legs direct to the load sensors and
not coupled to the case on the leg side.

I have always assumed that each foot has a strain gauge and the output
of each is added to give the final figure.


One teardown of an IKEA unit I just watched suggested the 4 load cells
were wired in a Wheatstone bridge to sum up in an analogue fashion:

https://learn.sparkfun.com/tutorials...80308721.15098

I wonder if that means any differences in each cell cause a non perfect
summation and thus variation depending on how the load is distributed???
I don't know.

In message , fred
writes
I made a small platform with 4 spikes screwed into each corner. They
pierce the carpet and alow the scales contact the hard surface
underneath

Well, my test this morning seemed to show that all you needed was the
hard, flat platform. My tile just sat on the carpet and the scales
placed on it read correctly.
--
Bill

---
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On Tue, 2 Oct 2018 19:37:09 +1000, Andew Jones, better known as
cantankerous trolling senile geezer Rot Speed, wrote:

Very probably someone does but not at a price point to capture much of the
existing domestic market where the accuracy of widely available products
is adequate, if used properly.

There is no reason why it costs more and very few
of the domestic products even give a reproducible
reading, let alone an accurate one.

It's always a matter of price, you senile cheapskate who brags about having
"money to burn"!

--
Bill Wright addressing senile Ozzie cretin Rot Speed:
"Well you make up a lot of stuff and it's total ******** most of it."
MID:

Martin Brown has brought this to us :
To make them work on any surface would require much more rigid engineering of
the base plate which adds weight and materials cost.

I have a pair of digital bathroom scales from (I think) Aldi around ten
years ago. They have a glass top and what seems to be a fairly solid
cast alloy base/under frame like an H. You give them a kick, to wake
them up. I regularly check them against calibrated scales and they
always show to be on the nose (+/- 0.1Kg). They seem not to care at all
what sort of surface they are used on, so long as you stand reasonably
on the centre.

"Tim Watts" wrote in message
...
On 02/10/18 11:00, Andew Jones wrote:


"Tim Watts" wrote in message
...
On 02/10/18 09:56, Andew Jones wrote:
But no one does that.

There must be a reason why no one does that.

I was wrong on one count:

It seems, having watched some YT teardown vids, that a lot of cheap
modern scales do have 4 load sensors, one on each foot.

So the problem, apart from how accurate the load sensor is, comes down
to the carpet pile under the very slim base bypassing the sensors and
pressing on say the battery compartment.

All those need, in theory, is longer legs direct to the load sensors and
not coupled to the case on the leg side.

It can't be that easy or everyone would be doing it.


Not necessarily. It's easy to use conduit for all cables runs in walls
when building a house. Cost: next to sod all extra. No one does it (well,
I did when renovating).

Why? Lazy, cheapskate-ness, "The builder doesn't have to live with fixing
it", etc.

That isnt the way things like bathroom scales are DESIGNED.

"Martin Brown" wrote in message
news
On 02/10/2018 10:37, Andew Jones wrote:


"alan_m" wrote in message
...
On 02/10/2018 09:56, Andew Jones wrote:

There must be a reason why no one does that.

Very probably someone does but not at a price point to capture much of
the existing domestic market where the accuracy of widely available
products is adequate, if used properly.

+1

There is no reason why it costs more and very few
of the domestic products even give a reproducible
reading, let alone an accurate one.

I disagree. My bathroom scales under read by an amount determined by the
carpet thickness but they are extremely consistent about how much.

Thats a fudge done by the scale, it keeps using the original reading
for the later readings, doesnt actually keep measuring the weight.

You can prove that by tricking it by getting it to measure two
different weights and running a test with each weight used
alternately. That stops it fudging and you will find that most
domestic bathroom scales aren't very reproducible at all in that test.

To make them work on any surface would require much more rigid engineering
of the base plate which adds weight and materials cost.

My kitchen scales which get used on a level rigid surface are accurate to
the claimed precision of 5g on up to 3kg. There is a bit of hysteresis and
stiction on the very low end which means weighting several identical Xmas
cards to work out airmail charges reliably.

On 02/10/18 20:11, Andew Jones wrote:

Why? Lazy, cheapskate-ness, "The builder doesn't have to live with
fixing it", etc.

That isnt the way things like bathroom scales are DESIGNED.

They're designed to a price, to look good and to get a sale.

There seems to be little consideration made about the environment in
which they are used, or their longevity, like so many consumer products.

I am certain they could design a reasonably cost effective set of scales
that would function to +/- 2% accuracy and +/-0.2% repeatability across
a range of floor types and off level floors *if they wanted too*.

But no one seems to. Just making the feet longer would help - then
ensuring the load cells would sum fairly accurately with imbalanced loads.

On Wed, 3 Oct 2018 05:11:34 +1000, Andew Jones, better known as
cantankerous trolling senile geezer Rot Speed, wrote:


Not necessarily. It's easy to use conduit for all cables runs in walls
when building a house. Cost: next to sod all extra. No one does it (well,
I did when renovating).

Why? Lazy, cheapskate-ness, "The builder doesn't have to live with fixing
it", etc.

That isnt the way things like bathroom scales are DESIGNED.

That's what he complained about, asshole!

--
Sqwertz to Rot Speed:
"This is just a hunch, but I'm betting you're kinda an argumentative
asshole.
MID:

Digital Scales those are what Sher sings on her new Abba songs cd.
Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Tim Watts" wrote in message
...
On 01/10/18 18:19, Bill wrote:
As part of my crusade to clear some of my old junk from the house, I have
been using Freecycle and ebay.

On a related note, I found Freegle to be very good when I used it the
other day. Much updated with som every nice features to make posting
photos and handling enquiries easier. There was a "promise it to X" option
which is nice (it greys it out to let others know someone has dibs) and a
"Release my address". Small things but compared to the last time I used
Freecycle, saved a lot of messaging.

"Tim Watts" wrote in message
...
On 02/10/18 20:11, Andew Jones wrote:

Why? Lazy, cheapskate-ness, "The builder doesn't have to live with
fixing it", etc.

That isnt the way things like bathroom scales are DESIGNED.

They're designed to a price, to look good and to get a sale.

They are in fact designed to show your weight.

Turns out that it isnt easy to show you your weight reproducibly,
let alone accurately. It is possible to do that and commercial
scales obviously do that, but they are much more expensive
and few are prepared to pay that much higher price.

There seems to be little consideration made about the environment in which
they are used,

Thats wrong with the type of floor they are used on.

or their longevity, like so many consumer products.

I am certain they could design a reasonably cost effective set of scales
that would function to +/- 2% accuracy and +/-0.2% repeatability across a
range of floor types and off level floors *if they wanted too*.

They clearly do with commercial scales, but those are much more
expensive than domestic bathroom scales.

But no one seems to. Just making the feet longer would help

It doesnt and some have tried doing that with domestic bathroom scales.

- then
ensuring the load cells would sum fairly accurately with imbalanced loads.

That is what they do.

On Wed, 3 Oct 2018 06:07:46 +1000, Andew Jones, better known as
cantankerous trolling senile geezer Rot Speed, wrote:

alternately. That stops it fudging and you will find that most
domestic bathroom scales aren't very reproducible at all in that test.

He will soon find what a pathological "argumentative asshole" and
all-knowing wiseacre you are, Rot! BG

--
pamela about Rot Speed:
"His off the cuff expertise demonstrates how little he knows..."
MID:

On Wed, 3 Oct 2018 07:31:48 +1000, Andew Jones, better known as
cantankerous trolling senile geezer Rot Speed, wrote:


They're designed to a price, to look good and to get a sale.

They are in fact designed to show your weight.

More or less accurately, depending on the price, senile wisenheimer!

--
Bill Wright addressing senile Ozzie cretin Rot Speed:
"Well you make up a lot of stuff and it's total ******** most of it."
MID:

Andew Jones laid this down on his screen :
It is possible to do that and commercial
scales obviously do that, but they are much more expensive
and few are prepared to pay that much higher price.

I can buy and have bought, multi-meters costing hundreds of pounds and
I have bought cheap ones at a fiver a time. The later I generally find
to be very close to the accuracy of the expensive ones. The difference
is mostly down to build quality and robustness. Likewise with scales...

Mine were fairly cheap ones, but I check and compare them against
expensive calibrated ones, when ever I get the opportunity and find
them to be spot on. Were I to find any discrepancy, my first thought
would be that the reference I had checked them against was in error,
rather than my bathroom scales.

I have a cheap Sekonda watch, which I found (yes found) abandoned on a
bank roof. It is an electronic analogue type. That watch is accurate to
one second per month, which is incredible accuracy for any watch which
is not radio controlled.

I have a £5 set of cheap 0.1 to 100 gram digital scales which measure
to 0.1 of a gram and a set of gram weight calibration standards. when I
check their calibration, these always show up to be spot on.

So I am not convinced that cheap always means poor accuracy and I am
someone who is obsessed about accuracy. I have voltage, currant and
resistance standards, frequency standards - I like to know my equipment
is accurate.

"Harry Bloomfield" wrote in message
news
Andew Jones laid this down on his screen :
It is possible to do that and commercial
scales obviously do that, but they are much more expensive
and few are prepared to pay that much higher price.

I can buy and have bought, multi-meters costing hundreds of pounds and I
have bought cheap ones at a fiver a time. The later I generally find to be
very close to the accuracy of the expensive ones.

Yes, but bathroom scales are different.

The difference
is mostly down to build quality and robustness.

With multimeters, yes, and how well the survive you
doing something stupid like attempting to measure
the mains voltage when on the current setting.

Likewise with scales...

Not with bathroom scales with repeatability and accuracy.

Mine were fairly cheap ones, but I check and compare them against
expensive calibrated ones, when ever I get the opportunity and find them
to be spot on.

How do you actually do that check ?

Were I to find any discrepancy, my first thought
would be that the reference I had checked them against was in error,
rather than my bathroom scales.

More fool you. It is trivial to check your own bathroom scales with
a know fixed weight.

I have a cheap Sekonda watch, which I found (yes found) abandoned on a
bank roof. It is an electronic analogue type. That watch is accurate to
one second per month, which is incredible accuracy for any watch which is
not radio controlled.

Irrelevant to bathroom scales.

I have a £5 set of cheap 0.1 to 100 gram digital scales which measure to
0.1 of a gram and a set of gram weight calibration standards. when I check
their calibration, these always show up to be spot on.

Irrelevant to bathroom scales which can be checked the same way.

So I am not convinced that cheap always means poor accuracy

No one ever said that with bathroom scales.

and I am
someone who is obsessed about accuracy. I have voltage, currant and
resistance standards, frequency standards -

And it is even easier with bathroom scales.

I like to know my equipment
is accurate.

Graham. wrote:

Bill wrote:

item weights were all over the place.

You need a hard flat surface!
The carpet is acting like a spring and is sharing the force with the
strain gauges in the scale, that's why you get a lower reading.

ISTR a pair of bathroom/bedroom scales that came with optional carpet
feet to concentrate the force into for smaller 'points' to reduce that
effect