OT Sensor
Archiver
Posts: 46,084
Not only is this forum good for Basic Stamps, but hardware stuff too..........
Any suggestions/links for hardware that will measure displacement with a
resolution of 0.0001".
First thought is a micrometer with a serial output, but looking for other
possible ideas.
A while back somebody posted a home brew LVDT, if the creator of that LVDT
reads this, what resolution did you get?
[noparse][[/noparse]Non-text portions of this message have been removed]
Any suggestions/links for hardware that will measure displacement with a
resolution of 0.0001".
First thought is a micrometer with a serial output, but looking for other
possible ideas.
A while back somebody posted a home brew LVDT, if the creator of that LVDT
reads this, what resolution did you get?
[noparse][[/noparse]Non-text portions of this message have been removed]
Comments
the end of a thread. You can easily achieve one micron resolution with a
1000 count encoder on a 1mm thread. Inexpensive encoder wheels can be
bought here.
http://www.encoders.com/products/optical-encoders.shtml?source=google
Dave
Original Message
From: smartdim@a... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=yXx15TCMTQElf33KodyWjEWdoHVFT5YW6Yf1T8QzIxPrBYRYtDFLPl03CFER5_C6ZruJsaqF6HKql30]smartdim@a...[/url
Sent: Friday, September 26, 2003 9:32 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] OT Sensor
Not only is this forum good for Basic Stamps, but hardware stuff
too..........
Any suggestions/links for hardware that will measure displacement with a
resolution of 0.0001".
First thought is a micrometer with a serial output, but looking for
other
possible ideas.
A while back somebody posted a home brew LVDT, if the creator of that
LVDT
reads this, what resolution did you get?
[noparse][[/noparse]Non-text portions of this message have been removed]
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waddell@p... writes:
One of the easiest ways to do this is with an encoder wheel mounted on
the end of a thread. You can easily achieve one micron resolution with a
1000 count encoder on a 1mm thread. Inexpensive encoder wheels can be
bought here.
http://www.encoders.com/products/optical-encoders.shtml?source=google
Dave
______________________________________
Thank you Dave!
[noparse][[/noparse]Non-text portions of this message have been removed]
inch (0.0005) from a homemade LVDT... The main consideration is
temperature compensation, otherwise the amount of drift will severely
impact your results. Most of the examples that I have given over
the years involve a "free-running" oscillator, where a COIL of some
sort is part of the resonate circuit. The latest tests I was working
on before I changed jobs in 2000, involved a PI (Pulse Induction)
method for reading the coil, which provided faster coil sampling, and
was much more impervious to temperature variations.
I must say, I am curious as to why you need the 10 thousandth of an inch
resolution.
Try visiting:
http://groups.yahoo.com/group/basicstamps/
... and searching for these various topics below to see what I have
contributed to the list since 2000. Somewhere I think there is an archive
dating back further that might provide early E-mails where I myself
discovered the LVDT concept in the early to mid 90's.
Impact Sensor
Force Sensor
Measuring weight
LVDT or LDVDT
Linear displacement
Beau Schwabe - Mask Designer II
National Semiconductor
>Not only is this forum good for Basic Stamps, but hardware stuff too..........
>
>Any suggestions/links for hardware that will measure displacement with a
>resolution of 0.0001".
>
>First thought is a micrometer with a serial output, but looking for other
>possible ideas.
>
>A while back somebody posted a home brew LVDT, if the creator of that LVDT
>reads this, what resolution did you get?
(tenth) of an inch over 8 inches. Very common machinests level.
many milling machines and many metal working machines can do better
than one tenth. Surface grinders take more than a few passes to get
one tenth off a piece of metal.
My CNC machine takes 26,000 steps per inch, not for accuracy but for
torque reasons. I don't pretend that it is accurate, but it repeats
very well to one thousandth. I did speed it up as when it was doing
52,000 steps per inch it was too slow.
Astromony tracking for photographic reasons need better than one
tenth.
Dave
--- In basicstamps@yahoogroups.com, "Beau Schwabe" <bschwabe@a...>
wrote:
> The best resolution that I have observed is roughly 1/2000th of an
> inch (0.0005) from a homemade LVDT... The main consideration is
> temperature compensation, otherwise the amount of drift will
severely
> impact your results. Most of the examples that I have given over
> the years involve a "free-running" oscillator, where a COIL of some
> sort is part of the resonate circuit. The latest tests I was
working
> on before I changed jobs in 2000, involved a PI (Pulse Induction)
> method for reading the coil, which provided faster coil sampling,
and
> was much more impervious to temperature variations.
>
> I must say, I am curious as to why you need the 10 thousandth of an
inch
> resolution.
>
> Try visiting:
> http://groups.yahoo.com/group/basicstamps/
>
> ... and searching for these various topics below to see what I have
> contributed to the list since 2000. Somewhere I think there is an
archive
> dating back further that might provide early E-mails where I myself
> discovered the LVDT concept in the early to mid 90's.
>
> Impact Sensor
> Force Sensor
> Measuring weight
> LVDT or LDVDT
> Linear displacement
>
>
> Beau Schwabe - Mask Designer II
> National Semiconductor
>
> >Not only is this forum good for Basic Stamps, but hardware stuff
too..........
> >
> >Any suggestions/links for hardware that will measure displacement
with a
> >resolution of 0.0001".
> >
> >First thought is a micrometer with a serial output, but looking
for other
> >possible ideas.
> >
> >A while back somebody posted a home brew LVDT, if the creator of
that LVDT
> >reads this, what resolution did you get?
of interferometry. I've not done it, but colleagues in hearing research
use this approach to measure small movements of parts of the cochlea
(hearing receptor in the inner ear).
Dennis
Original Message
From: Beau Schwabe [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=MrlkK9fsyaruHIXG0RzEh6iIrqY_CIzd-0_cZc_YufWNUCPfx6YxFVOBv0in8Tw7AE4StfLX-wc1g5UJyR2GyA]bschwabe@a...[/url
Sent: Monday, September 29, 2003 2:47 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] OT Sensor
The best resolution that I have observed is roughly 1/2000th of an inch
(0.0005) from a homemade LVDT... The main consideration is temperature
compensation, otherwise the amount of drift will severely impact your
results. Most of the examples that I have given over the years involve
a "free-running" oscillator, where a COIL of some sort is part of the
resonate circuit. The latest tests I was working on before I changed
jobs in 2000, involved a PI (Pulse Induction) method for reading the
coil, which provided faster coil sampling, and was much more impervious
to temperature variations.
I must say, I am curious as to why you need the 10 thousandth of an inch
resolution.
Try visiting:
http://groups.yahoo.com/group/basicstamps/
... and searching for these various topics below to see what I have
contributed to the list since 2000. Somewhere I think there is an
archive dating back further that might provide early E-mails where I
myself discovered the LVDT concept in the early to mid 90's.
Impact Sensor
Force Sensor
Measuring weight
LVDT or LDVDT
Linear displacement
Beau Schwabe - Mask Designer II
National Semiconductor
>Not only is this forum good for Basic Stamps, but hardware stuff
>too..........
>
>Any suggestions/links for hardware that will measure displacement with
>a resolution of 0.0001".
>
>First thought is a micrometer with a serial output, but looking for
>other possible ideas.
>
>A while back somebody posted a home brew LVDT, if the creator of that
>LVDT reads this, what resolution did you get?
To UNSUBSCRIBE, just send mail to:
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> the years involve a "free-running" oscillator, where a COIL of some
> sort is part of the resonate circuit. The latest tests I was
working
> on before I changed jobs in 2000, involved a PI (Pulse Induction)
> method for reading the coil, which provided faster coil sampling,
and
> was much more impervious to temperature variations.
> Beau Schwabe - Mask Designer II
> National Semiconductor
Hi Beau,
I've reviewd your circuit using a coil as a free running oscillator,
but not the pulse induction.
do you have any examples ?
any tips ?
Dave
> > Most of the examples that I have given over
> > the years involve a "free-running" oscillator, where a COIL of some
> > sort is part of the resonate circuit. The latest tests I was
>working
> > on before I changed jobs in 2000, involved a PI (Pulse Induction)
> > method for reading the coil, which provided faster coil sampling,
>and
> > was much more impervious to temperature variations.
>
>
> > Beau Schwabe - Mask Designer II
> > National Semiconductor
>
>
>Hi Beau,
>
>I've reviewd your circuit using a coil as a free running oscillator,
>but not the pulse induction.
>
>do you have any examples ?
>
>any tips ?
>
>Dave
I can't give you any complete schematics, because this was when I was with
another company, and they own the rights. I can however explain some of
the theory.
Consider a basic coil test circuit for a scope:
D
o
|<
o--->GND
R | |
Square Wave>---/\/\---o---[noparse][[/noparse]COIL]---o
|
o
>Scope
There are two noticeable components that are effected by inductance changes
to the coil. One is the 'time' interval in which the spike takes to decay,
the Other is the 'amplitude' of the spike. You can use one or both methods
for accurate coil readings with a proper conditioning circuit. (Several ways
to skin a cat here)
Note: A single PULSE or PING to the coil is sufficient for an accurate
reading with this design.
Beau Schwabe - Mask Designer II
National Semiconductor
1/2 of a 1/10(0.0005) These are used in CMMS which are very accurate.
Leroy
Original Message
From: "Beau Schwabe" <bschwabe@a...>
To: <basicstamps@yahoogroups.com>
Sent: Monday, September 29, 2003 4:46 PM
Subject: Re: [noparse][[/noparse]basicstamps] OT Sensor
: The best resolution that I have observed is roughly 1/2000th of an
: inch (0.0005) from a homemade LVDT... The main consideration is
: temperature compensation, otherwise the amount of drift will severely
: impact your results. Most of the examples that I have given over
: the years involve a "free-running" oscillator, where a COIL of some
: sort is part of the resonate circuit. The latest tests I was working
: on before I changed jobs in 2000, involved a PI (Pulse Induction)
: method for reading the coil, which provided faster coil sampling, and
: was much more impervious to temperature variations.
:
: I must say, I am curious as to why you need the 10 thousandth of an inch
: resolution.
:
: Try visiting:
: http://groups.yahoo.com/group/basicstamps/
:
: ... and searching for these various topics below to see what I have
: contributed to the list since 2000. Somewhere I think there is an archive
: dating back further that might provide early E-mails where I myself
: discovered the LVDT concept in the early to mid 90's.
:
: Impact Sensor
: Force Sensor
: Measuring weight
: LVDT or LDVDT
: Linear displacement
:
:
: Beau Schwabe - Mask Designer II
: National Semiconductor
:
: >Not only is this forum good for Basic Stamps, but hardware stuff
too..........
: >
: >Any suggestions/links for hardware that will measure displacement with a
: >resolution of 0.0001".
: >
: >First thought is a micrometer with a serial output, but looking for other
: >possible ideas.
: >
: >A while back somebody posted a home brew LVDT, if the creator of that LVDT
: >reads this, what resolution did you get?
:
:
:
: To UNSUBSCRIBE, just send mail to:
: basicstamps-unsubscribe@yahoogroups.com
: from the same email address that you subscribed. Text in the Subject and Body
of the message will be ignored.
:
:
: Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
:
:
:
Yes, I absolutely agree that a properly designed and configured LVDT capable
of measuring Microns, even sub-Micron measurements is possible. ...But
not from a "homemade" variety as I describe.
Beau Schwabe - Mask Designer II
National Semiconductor
>I would expect a properly designed and configured LVDT to measure in
>Microns not
>1/2 of a 1/10(0.0005) These are used in CMMS which are very accurate.
>
>
>Leroy
>
>
Original Message
>From: "Beau Schwabe" <bschwabe@a...>
>To: <basicstamps@yahoogroups.com>
>Sent: Monday, September 29, 2003 4:46 PM
>Subject: Re: [noparse][[/noparse]basicstamps] OT Sensor
>
>
>: The best resolution that I have observed is roughly 1/2000th of an
>: inch (0.0005) from a homemade LVDT... The main consideration is
>: temperature compensation, otherwise the amount of drift will severely
>: impact your results. Most of the examples that I have given over
>: the years involve a "free-running" oscillator, where a COIL of some
>: sort is part of the resonate circuit. The latest tests I was working
>: on before I changed jobs in 2000, involved a PI (Pulse Induction)
>: method for reading the coil, which provided faster coil sampling, and
>: was much more impervious to temperature variations.
>:
>: I must say, I am curious as to why you need the 10 thousandth of an inch
>: resolution.
>:
>: Try visiting:
>: http://groups.yahoo.com/group/basicstamps/
>:
>: ... and searching for these various topics below to see what I have
>: contributed to the list since 2000. Somewhere I think there is an archive
>: dating back further that might provide early E-mails where I myself
>: discovered the LVDT concept in the early to mid 90's.
>:
>: Impact Sensor
>: Force Sensor
>: Measuring weight
>: LVDT or LDVDT
>: Linear displacement
>:
>:
>: Beau Schwabe - Mask Designer II
>: National Semiconductor
>:
>: >Not only is this forum good for Basic Stamps, but hardware stuff
>too..........
>: >
>: >Any suggestions/links for hardware that will measure displacement with a
>: >resolution of 0.0001".
>: >
>: >First thought is a micrometer with a serial output, but looking for other
>: >possible ideas.
>: >
>: >A while back somebody posted a home brew LVDT, if the creator of that LVDT
>: >reads this, what resolution did you get?
>: