>
> On Fri, 12 Sep 2003 12:40:21 -0400, Jerry Avins <jya@ieee.org> wrote:
>
> >Jerry Avins wrote:
> >>
> > ...
> >
> >> see http://www.phy.ntnu.edu.tw/java/ruler/vernier.html
> >>
> >The applet reads to the nearest .1 mm. In practice, .05 mm is easily
> >estimated.
> >
> >Jerry
>
> I have an el-cheap-o Vernier caliper in the garage that I've been
> using over the summer to build parts for the track car. I've been
> corroborating through email with some other people so that we can pool
> parts orders, etc. We had a snafu in some unexpected deviations in
> part sizes from car to car, and I measured mine with the Vernier
> calipers, duly noting inches, tenths, and hundredths and reporting
> them to my colleagues (since I was the first to encounter the
> problem).
>
> I usually use the metric side of it, but in this case we were ordering
> sleeves that were only specified in inches. It turned out that what I
> had thought was inches, tenths, and hundredths, was really inches,
> eighths, and 64ths (or something like that). It was really
> aggravating, although completely my fault.
>
> They're a little tough on the eyeballs, too.
>
> Since then I've sprung the $$ for a nice digital caliper, so that I am
> far less apt to make such errors and suffer the combined scorn of my
> unforgiving associates. ;)
>
> Eric Jacobsen
> Minister of Algorithms, Intel Corp.
> My opinions may not be Intel's opinions.
> http://www.ericjacobsen.org
I have an old caliper that I got for a song at a flea market whose shape
makes it useful for some things my newer ones won't fit. It too has an
inch scale marked in sixteenths, and the vernier reads to 256ths. It's
much harder to read than my "modern" one from Starrett that reads in
20ths and thousandths, interpolates to .0005. Like you, I mainly use the
digital. I like being able do measure differences by setting any opening
to be zero. It reads .0005, but I don't know how accurately. Mt one-nch
screw micrometer reads to .0001 and interpolates to .00005. Except for
optics and gyros, if differences like that matter, it's designed wrong!
Jerry
--
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������
Reply by Jerry Avins●September 13, 20032003-09-13
Rune Allnor wrote:
>
...
>
> Thanks. I knew of that sliding fine-scale-measurement thing Jerry pointed
> to (funny how all those *useful* words in a foreign language eludes you,
> even after practicing it for decades...), but I wasn't aware of the term
> itself, nor the generalization.
>
> Rune
Vernier is (almost) a French name. From
http://www-gap.dcs.st-and.ac.uk/~history/Mathematicians/Vernier.html :
Pierre Vernier was taught mathematics and science by his father who was
a lawyer and engineer who held government office. His father introduced
Pierre to the works of Clavius and Brahe.
Being born in Franche-Comt� (Free Country) meant that Vernier (and his
father) were involved, not with the government of France but with that
of Spain. Franche-Comt� was a Hapsburg possession controlled by the
Spanish Hapsburgs throughout Vernier's life. In fact the period from
1598 to 1635 was one of peace.
Vernier became a government official holding various positions such as
military engineer for the Hapsburgs and director general of the treasury
in Dole and Besan�on, the capital of Franche-Comt�. Vernier also held
various government posts with the government of Spain and became a
Conseiller du Roi.
He worked for much of the time as an engineer, working on the
fortifications of various cities. In 1623 he was given the title of
citizen from the city of Besan�on for his work on the defenses of the
city. In fact the threat of war was never far away and during the last
two years of Vernier's life Franche-Comt� was frequently invaded by
France.
Like many other mathematicians and scientists of this period, Vernier
worked on cartography and on surveying. He collaborated with his father
in making a map of the Franche-Comt� area. His interest in surveying led
to develop instruments for surveying and this prompted the invention for
which he is remembered by all scientists.
His most famous publication is La Construction, l'usage, et les
propri�t�s du quadrant nouveau de math�matiques (1631). In this book
Vernier gives a table of sines and a method for deriving the angles of a
triangle if its sides are known. He also describes his most famous
invention, that of the vernier caliper, an instrument for accurately
measuring length. It has two graduated scales, a main scale like a ruler
and a second scale, the vernier, that slides parallel to the main scale
and enables readings to be made to a fraction of a division on the main
scale.
Article by: J J O'Connor and E F Robertson
Jerry
--
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������
Reply by Eric Jacobsen●September 12, 20032003-09-12
On Fri, 12 Sep 2003 12:40:21 -0400, Jerry Avins <jya@ieee.org> wrote:
I have an el-cheap-o Vernier caliper in the garage that I've been
using over the summer to build parts for the track car. I've been
corroborating through email with some other people so that we can pool
parts orders, etc. We had a snafu in some unexpected deviations in
part sizes from car to car, and I measured mine with the Vernier
calipers, duly noting inches, tenths, and hundredths and reporting
them to my colleagues (since I was the first to encounter the
problem).
I usually use the metric side of it, but in this case we were ordering
sleeves that were only specified in inches. It turned out that what I
had thought was inches, tenths, and hundredths, was really inches,
eighths, and 64ths (or something like that). It was really
aggravating, although completely my fault.
They're a little tough on the eyeballs, too.
Since then I've sprung the $$ for a nice digital caliper, so that I am
far less apt to make such errors and suffer the combined scorn of my
unforgiving associates. ;)
Eric Jacobsen
Minister of Algorithms, Intel Corp.
My opinions may not be Intel's opinions.
http://www.ericjacobsen.org
Reply by Rune Allnor●September 12, 20032003-09-12
Stan Pawlukiewicz <stanp@nospam_mitre.org> wrote in message news:<bjsq29$90j$1@newslocal.mitre.org>...
> Rune Allnor wrote:
> > Stan Pawlukiewicz <stanp@nospam_mitre.org> wrote in message news:<bjo33t$a04$1@newslocal.mitre.org>...
> >
> >
> >>Back in the old days, one used knobs, led's, and other archaic forms of
> >>user interface. One might have used some sort of digital encoder to
> >>select something like a frequency. Integers would have a nice smooth
> >>vernier control as you hunt for a specific frequency.
> >
> >
> > At the chance of displaying my ignorance, what is a "vernier control"?
> > I have seen the term once or twice before and I can't find it in my
> > dictionary.
> >
> > Rune
> My apologies.
>
> In the part of the woods I grew up, central Connecticut (high school
> shop had more stuff than UCONN's), the knob on a micrometer was called
> often called a vernier, some called the focus knob on telescope eye
> piece a vernier. The term was loosely applied to many fine scaled
> adjustment knobs on machines and instruments.
Thanks. I knew of that sliding fine-scale-measurement thing Jerry pointed
to (funny how all those *useful* words in a foreign language eludes you,
even after practicing it for decades...), but I wasn't aware of the term
itself, nor the generalization.
Rune
Reply by Glenn Dixon●September 12, 20032003-09-12
allnor@tele.ntnu.no (Rune Allnor) wrote in message news:<f56893ae.0309120607.3aad6d3e@posting.google.com>...
> Stan Pawlukiewicz <stanp@nospam_mitre.org> wrote in message news:<bjo33t$a04$1@newslocal.mitre.org>...
>
> > Back in the old days, one used knobs, led's, and other archaic forms of
> > user interface. One might have used some sort of digital encoder to
> > select something like a frequency. Integers would have a nice smooth
> > vernier control as you hunt for a specific frequency.
>
> At the chance of displaying my ignorance, what is a "vernier control"?
> I have seen the term once or twice before and I can't find it in my
> dictionary.
>
> Rune
After the French mathematician Pierre Vernier. Before digital
calipers and dial calipers, there were Vernier calipers. The lowest
significant digit of the measurement was determined by matching a
scale marked with ten increments against one where the same distance
was marked with nine. It gave pretty fine precision in its day. The
term Vernier later came to mean anything with fine adjustment, so a
Vernier control had two knobs: one for course adjustment, and one for
fine.
Glenn Dixon
The applet reads to the nearest .1 mm. In practice, .05 mm is easily
estimated.
Jerry
--
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������
Reply by Jerry Avins●September 12, 20032003-09-12
Rune Allnor wrote:
>
> Stan Pawlukiewicz <stanp@nospam_mitre.org> wrote in message news:<bjo33t$a04$1@newslocal.mitre.org>...
>
> > Back in the old days, one used knobs, led's, and other archaic forms of
> > user interface. One might have used some sort of digital encoder to
> > select something like a frequency. Integers would have a nice smooth
> > vernier control as you hunt for a specific frequency.
>
> At the chance of displaying my ignorance, what is a "vernier control"?
> I have seen the term once or twice before and I can't find it in my
> dictionary.
>
> Rune
I assume you know what a Vernier scale is, and how to read one. If not,
see http://www.phy.ntnu.edu.tw/java/ruler/vernier.html
As an analogy with a Vernier scale which allows one to read a coarse
scale with high precision, controls that allow fine adjustments, like
the extra narrow-range voltage control on a power supply are called
Vernier knobs, with or without capitalizing the inventor's name. (On a
microscope, it is called "fine focus". If Stan were describing one
without knowing the usual nomenclature -- hardly conceivable! -- he
might call it "vernier focus".)
Jerry
--
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������
Reply by Stan Pawlukiewicz●September 12, 20032003-09-12
Rune Allnor wrote:
> Stan Pawlukiewicz <stanp@nospam_mitre.org> wrote in message news:<bjo33t$a04$1@newslocal.mitre.org>...
>
>
>>Back in the old days, one used knobs, led's, and other archaic forms of
>>user interface. One might have used some sort of digital encoder to
>>select something like a frequency. Integers would have a nice smooth
>>vernier control as you hunt for a specific frequency.
>
>
> At the chance of displaying my ignorance, what is a "vernier control"?
> I have seen the term once or twice before and I can't find it in my
> dictionary.
>
> Rune
My apologies.
In the part of the woods I grew up, central Connecticut (high school
shop had more stuff than UCONN's), the knob on a micrometer was called
often called a vernier, some called the focus knob on telescope eye
piece a vernier. The term was loosely applied to many fine scaled
adjustment knobs on machines and instruments.
Floating point numbers are sort of log spaced. Integers have a uniform
increment. My basic point is that I would use integers if I wanted an
adjustment to emulate a micrometer vernier.
Reply by Rune Allnor●September 12, 20032003-09-12
Stan Pawlukiewicz <stanp@nospam_mitre.org> wrote in message news:<bjo33t$a04$1@newslocal.mitre.org>...
> Back in the old days, one used knobs, led's, and other archaic forms of
> user interface. One might have used some sort of digital encoder to
> select something like a frequency. Integers would have a nice smooth
> vernier control as you hunt for a specific frequency.
At the chance of displaying my ignorance, what is a "vernier control"?
I have seen the term once or twice before and I can't find it in my
dictionary.
Rune
> Jon Harris wrote:
> >
> > I'm trying to find and plot the frequency response of a single bin from
a
> > DFT/FFT. Then, as an extension, I'd also like to do the same for the
> > Goertzel algorithm implemented with non-integer 'k', i.e. centered at an
> > arbitrary frequency. Any pointers or tips? Matlab code would be ideal.
>
> I've got a not-too-embarrasing C implementation of the goertzel
> transform here:
>
> http://leesburg.bittware.com/goertzel.tgz
>
> It has an open_goertzel() function that calculates a floting-point k
> based on a center frequency (freq) and sample rate (fs). I dunno why I
> coded freq and fs as ints though.
>
> --
> Jim Thomas Principal Applications Engineer Bittware, Inc
> jthomas@bittware.com http://www.bittware.com (703) 779-7770
> Unix IS user friendly. It's just more particular about its friends.