next message in archive
next message in thread
previous message in archive
previous message in thread
Index of Subjects
Index of Subjects
--Apple-Mail-1-210861465
Content-Transfer-Encoding: 7bit
Content-Type: text/plain;
charset=US-ASCII;
format=flowed
Hi Dave and all 2 others...
My e-mail seems to be working generally but I'm not sure about
NatureNS: one of mine didn't go through and the same one sent later
(re. your bathroom scale conundrum) took a long time. Despite your
comment about slow times, I get quite a lot of messages on NatureNS but
maybe not all: you refer to one on this erudite topic by 'Peter' -- I
didn't get that one -- but then on 2nd thoughts maybe it was sent to
you privately.
I'd only comment further that battery fatigue is universal though
varies by species, but that wouldn't be the likely explanation. All
integrated circuits these days would be driven by a power supply at an
early stage of which would be a voltage regulator chip or circuit that
drops the battery's own voltage from 9V or whatever it is, to a smaller
voltage presented to the circuit, 6 volts say (it varies). As long as
the battery can put out the required current at more than this 6V, the
circuit and display will mosey along as before, so will continue to be
accurate to the same degree. Once below 6V it's unregulated and bad
things will happen.
However, the digital scale readout will almost certainly have a 'low
battery' icon, and if you have been weighing yourself long after that
icon has come on, all bets are off -- the circuit will at some point
misbehave before the output finally vanishes altogether. So maybe you
need to stock up on alkaline batteries (no specific advertising here,
but see review in Consumer Reports about 2 issues back) instead of just
paying attention to those calories?
Steve
P.S. why not google to find the scale manufacturer's website and log
into their web or e-mail support and ask them? After all this, I'd
like to know the real answer.
*********************************
On 5-Dec-06, at 12:20 PM, David & Alison Webster wrote:
> Steve Shaw wrote:
>> Most likely with only 91 samples (not that many), it is going to look
>> noisy, but
>> when plotted, the result is actually quite striking and rather
>> simple. The
>> counts at all the even-numbered sample points (178, 180 etc) give a
>> reasonable,
>> normal-looking distribution of values centered on Dave = 180 lb, a
>> bit skewed
>> towards the low end. By contrast, the counts at all the odd-numbered
>> samples
>> (181, 183...) are relatively small and most are actually zero. So
>> the scale appears
>> to be counting in twos (almost).
>
> Hi Steve, Peter, Patrick & All, Dec 5, 2006
> The executive summary, as they say, is battery fatigue. And the
> short answer to 'why bother ?' is (a1) that much of our experience
> now passes through digital filters and (a2) much of nature is a
> puzzle.
>
> This tendency for a low incidence of odd weights was what led me to
> wonder about this in the first place and tabulate some of them.
>
> The various comments, including 91 being too few weights, got me
> past the energy barrier enough to tabulate all weights and look for
> possible mechanisms. Fot the total of 254 weights, only 47 were odd;
> the full array being--
> 192,1; 191,0; 190,1; 189,1; 188,3; 187,0; 186,4; 185,2; 184,11; 183,1;
> 182,21; 181,2; 180,29; 179,8; 178,24; 177,4; 176,43; 175,10; 174,16;
> 173,4; 172,21; 171,9; 170,8; 169,4; 168,16; 167,2; 166,8.
>
> To proceed further, some shorthand is indicated. The question is
> "V>x ?" represents "Does the output voltage of the transducer exceed
> the voltage that would be generated by a weight of x pounds ?" [Note
> that bathroom scales don't measure mass but weight. If you were in
> orbit then your mass would remain unchanged but the bathroom scales
> would say correctly that your weight was zero (if they worked
> correctly)].
>
> For a thumbnail reminder of how numbers are represented by digital
> switches and a key to additional jargon that I will use in this
> schematic representation of possible mechanism-- The output register
> is assumed to be 8 digital switches in which switches 1 to 8 (bits 1
> to 8) represent the numbers 1, 2, 4, 8, 16, 32, 64 & 128 respectively.
> Note that all numbers between 1 & 255 can be represented by
> combinations of these 8 values. If for example only bits 8 and 6 are
> set to 1, then the binary number is 00000101 which represents 32+128=
> 160.
> This unit runs on a 9 volt battery so circuit operations must be
> kept to a minimum. If the circuit logic worked from low to high (Is
> V>1 ?, if yes set bit 1; Is V>2 ?, If yes reset bit 1 and set bit
> 2...) it would use a lot of power asking stupid questions, activating
> redundant circuits and flicking gates on and off many times.
>
> Therefore the circuit should work from high to low--
> Is V>128 ? If yes then set bit 8 & goto B if no then is V>64 ?...; (B)
> Is V>(128 + 64) ? If yes then set bit 7 & goto C..., if no then is
> V>128+32 ?... The outcome of each test determines whether a bit will
> be set or not and also determines which branch of the circuit will
> next be used. So the last bit to be processed will be bit 1.
>
> If output voltage decreases, due to battery fatigue, while these
> necessary 8 questions are satisfied then even if there initially was
> enough output voltage to set bit 1 with some left over, in addition to
> all the other set bits, the voltage may have dropped too low to set
> bit 1 by the time question 8 is asked.
> One could test this idea by wiring a second 9 volt battery in
> parallel with the usual. This would take a fair amount of haywire, so
> as a first step I am running this past Naturens and as a second action
> will run it past a friend who has extensive electronics background.
>
> Yours truly, Dave Webster, Kentville
--Apple-Mail-1-210861465
Content-Transfer-Encoding: 7bit
Content-Type: text/enriched;
charset=US-ASCII
Hi Dave and all 2 others...
My e-mail seems to be working generally but I'm not sure about
NatureNS: one of mine didn't go through and the same one sent later
(re. your bathroom scale conundrum) took a long time. Despite your
comment about slow times, I get quite a lot of messages on NatureNS
but maybe not all: you refer to one on this erudite topic by 'Peter'
-- I didn't get that one -- but then on 2nd thoughts maybe it was sent
to you privately.
I'd only comment further that battery fatigue is universal though
varies by species, but that wouldn't be the likely explanation. All
integrated circuits these days would be driven by a power su