hooray for bathroom scales! on the hard wooden floor, this morning mine showed me at 101.1kg the first time, move it 2 inches to the right and then it showed 90.9kg. fuckin
this is a digital glass scale
are the actually mechanical ones any better?
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@davidgerard made me curious. I use a very cheap glass scale. Just checked what happens when I "simulate" an uneven floor, with one of its four legs in the air.
The answer is, it does not make a difference. And it should not, from what I remember. (Played with weight sensors and an Arduino years ago.)
@davidgerard Many years I asked an older medical person about scales, and which type I should get: digital, mechanical spring based, or what.
They told me that the only ones that don't need extensive calibration and maintenance are the old-fashioned ones with solid metal weights sliding along a bar. These cost a fortune and are fiddly, but they Just Work™.
Everything else, they said, whether mechanical or electronic or a mixture, is a guessing machine and one which can't be usefully calibrated.
Even if you measure your own weight accurately on a sliding-weights scale, then adjust your home one so it shows correctly, it absolutely will remain wrong for much lighter or heavier loads.
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My father used to calibrate industrial scales and measuring instruments for the government. Apparently, commercial bathroom scales are wildly imprecise and there’s not much you could do about it.
@davidgerard Same problem with mine but on ceramic tiles. Since the tiles are smaller than the scale, I have to find a spot where they're laid evenly enough for the scale to be stable. But depending on the exact spot, the measure can vary a lot.
It's better on the larger tiles in my living room, but putting the scale there is just goofy.
I think digital scales use piezos in their feet, and those require hard surfaces to work reliably. Try something harder than wood mayde ?
@davidgerard When ours start doing that, it's time to change the batteries and/or clean the grot out from underneath which is fouling the mechanics feeding into the strain gauge.
I'm also sorry to report that when such scales start reading inconsistently, they read low. So the true figure probably is 101.1kg or slightly more.
@pndc we changed the battery recently in hope of more accuracy, but i'll give it a scrape as well
@davidgerard
One stupid question, but it might be an issue: does the weight zeroes itself before stepping on?
Second question: does the floor bends in one of the places?
@davidgerard
Ad 1: good
Ad 2: I'm afraid if it even bends slightly that is not noticeable it will affect the measurement. But I won't make you check with a dial indicator or straight ruler.
I'd just go for the spot that shows higher (sorry).
(I'm trying hard not to infodump about strain gauges, Wheatstone bridges, and metrology overall :sweating choice guy: )
@davidgerard I’d just stay 2 inches to the right if I were you.
@davidgerard mine not only does the same thing as yours, but also the first measurement is wrong by a few kilos up. My routine is to place it within a single flat ceramic floor tile and then step on it to clear the first measurement and only then step on it again.