pendulum, accelerometer alternative? For Basic stamp2
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Posts: 46,084
Hi folks,
Im working on a project that involves measuring the movement of
pendulums, on one axis only. I had initially intended using
accelerometerss placed in the weight of the pendulum to give me the
information I need to give a continuously changing value that
indicated the amount of "swing" in one axis only.
The weights are suspended on fishing line, though the cabling
necessary for the accelerometer would be fed up the line as well. I
envisage the weights and length of line suspending the pendulums to
be great enough such that the cabling wont affect movement in any way
great enough to cause me problems...
Now, the real problem is, these Memsic Accelerometer devices are
quite expensive. I envisage having up to about 8 pendulums of
differing lengths
[url=etc....http://www.hvwtech.com/pages/products_view.asp?ProductID=373]etc....http://www.hvwtech.com/pages/products_view.asp?ProductID=373[/url]
They seem ideal really.....
Could anyone here suggest a cheaper, yest effective way of me being
able to measure the extent of the swing of the pendulum in one axis
only? It would have to be something that didnt impact the swing of
the weights too much, if at all.
Has anyone done something similar?
Any suggestions at all would be gratefully received...
Many thanks
Alan
Im working on a project that involves measuring the movement of
pendulums, on one axis only. I had initially intended using
accelerometerss placed in the weight of the pendulum to give me the
information I need to give a continuously changing value that
indicated the amount of "swing" in one axis only.
The weights are suspended on fishing line, though the cabling
necessary for the accelerometer would be fed up the line as well. I
envisage the weights and length of line suspending the pendulums to
be great enough such that the cabling wont affect movement in any way
great enough to cause me problems...
Now, the real problem is, these Memsic Accelerometer devices are
quite expensive. I envisage having up to about 8 pendulums of
differing lengths
[url=etc....http://www.hvwtech.com/pages/products_view.asp?ProductID=373]etc....http://www.hvwtech.com/pages/products_view.asp?ProductID=373[/url]
They seem ideal really.....
Could anyone here suggest a cheaper, yest effective way of me being
able to measure the extent of the swing of the pendulum in one axis
only? It would have to be something that didnt impact the swing of
the weights too much, if at all.
Has anyone done something similar?
Any suggestions at all would be gratefully received...
Many thanks
Alan
Comments
I don't know what kind of resolution you need, but how about
measuring the rotation at the top-side pivot point of the pendulum arm? In
this case it's the mounting point of the line that your weight hangs
from. If this point were to be a shaft or pulley that rotates with the
movement of the pendulum, you could have that rotation turn a potentiometer
(directly or through gears to adjust resolution) and measure that change
via an ADC or by using the RCtime instruction.
Food for thought,
Tim
>Could anyone here suggest a cheaper, yest effective way of me being
>able to measure the extent of the swing of the pendulum in one axis
>only? It would have to be something that didnt impact the swing of
>the weights too much, if at all.
>
>Has anyone done something similar?
>
>Any suggestions at all would be gratefully received...
>
>Many thanks
>
>
>Alan
>
>
>
>
>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.
>
>Yahoo! Groups Links
>
>
>
>
pendulum end, put an arm on a potentiometer and have that arm attached
against the pendulum weight with the pot positioned at the center of its
rotation. As the pendulum moves either way, it turns the pot -- you can
measure this as mentioned before. The attachment of the pot arm to the
weight would have to allow the arm to slide some -- maybe the arm could
slide through a close-fitting hole in the weight???
More to think about,
Tim
>Could anyone here suggest a cheaper, yest effective way of me being
>able to measure the extent of the swing of the pendulum in one axis
>only? It would have to be something that didnt impact the swing of
>the weights too much, if at all.
>
>Has anyone done something similar?
>
>Any suggestions at all would be gratefully received...
>
>Many thanks
>
>
>Alan
>
>
>
>
>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.
>
>Yahoo! Groups Links
>
>
>
>
the swing.
-- Jon Williams
-- Parallax
Original Message
From: advice_sought [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=oOehTbFSx-oEba1KmXz7L9ioUPoayWtxsMWa4xQn3gqStYYqiValUGIcZADzt6DsvAGpCytPS3M9f5xqLxA]aptn95@d...[/url
Sent: Tuesday, March 23, 2004 1:57 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative? For Basic
stamp2
Hi folks,
Im working on a project that involves measuring the movement of
pendulums, on one axis only. I had initially intended using
accelerometerss placed in the weight of the pendulum to give me the
information I need to give a continuously changing value that
indicated the amount of "swing" in one axis only.
The weights are suspended on fishing line, though the cabling
necessary for the accelerometer would be fed up the line as well. I
envisage the weights and length of line suspending the pendulums to
be great enough such that the cabling wont affect movement in any way
great enough to cause me problems...
Now, the real problem is, these Memsic Accelerometer devices are
quite expensive. I envisage having up to about 8 pendulums of
differing lengths
[url=etc....http://www.hvwtech.com/pages/products_view.asp?ProductID=373]etc....http://www.hvwtech.com/pages/products_view.asp?ProductID=373[/url]
They seem ideal really.....
Could anyone here suggest a cheaper, yest effective way of me being
able to measure the extent of the swing of the pendulum in one axis
only? It would have to be something that didnt impact the swing of
the weights too much, if at all.
Has anyone done something similar?
Any suggestions at all would be gratefully received...
Many thanks
Alan
Retails out of digikey and probably electrosonic too!
I just picked up the ADXL210AE for like $30 shipping and all. I didn't
think that was too much.
But this IS a mechanical device as opposed to memsics moving bubble method!
Original Message
From: "advice_sought" <aptn95@d...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, March 23, 2004 2:57 PM
Subject: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative? For Basic stamp2
> Hi folks,
>
> Im working on a project that involves measuring the movement of
> pendulums, on one axis only. I had initially intended using
> accelerometerss placed in the weight of the pendulum to give me the
> information I need to give a continuously changing value that
> indicated the amount of "swing" in one axis only.
>
> The weights are suspended on fishing line, though the cabling
> necessary for the accelerometer would be fed up the line as well. I
> envisage the weights and length of line suspending the pendulums to
> be great enough such that the cabling wont affect movement in any way
> great enough to cause me problems...
>
> Now, the real problem is, these Memsic Accelerometer devices are
> quite expensive. I envisage having up to about 8 pendulums of
> differing lengths
> [url=etc....http://www.hvwtech.com/pages/products_view.asp?ProductID=373]etc....http://www.hvwtech.com/pages/products_view.asp?ProductID=373[/url]
>
> They seem ideal really.....
>
> Could anyone here suggest a cheaper, yest effective way of me being
> able to measure the extent of the swing of the pendulum in one axis
> only? It would have to be something that didnt impact the swing of
> the weights too much, if at all.
>
> Has anyone done something similar?
>
> Any suggestions at all would be gratefully received...
>
> Many thanks
>
>
> Alan
>
>
>
>
> 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.
>
> Yahoo! Groups Links
>
>
>
>
>
photocell. Make the geometry such that on the far swing you cover most of
the photocell, and on the near swing you UNcover most of the photocell. Then
simply put the photocell in line with a pull-up resistor as a voltage
divider, and measure that value with an ADC on the Stamp. No friction, no
wear, etc... and you should be able to get sub-degree accuracy even with an
8-bit ADC. If you were very clever you could fix any non-linearity issues in
the geometry of the flag, or do a look-up table within the stamp itself.
Mike Sokol
mike@f...
www.fitsandstarts.com
" One should not increase, beyond what is necessary,
the number of entities required to explain anything"...
-William of Occam-
Original Message
From: "Jon Williams" <jwilliams@p...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, March 23, 2004 3:56 PM
Subject: RE: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative? For Basic
stamp2
> Hang your pendulum on the end of a pot shaft and use an ADC to measure
> the swing.
>
> -- Jon Williams
> -- Parallax
>
>
>
Original Message
> From: advice_sought [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=ofLTWGxmbLayuJDTo7tLC4mEdyRqkw0DrB-QlVTkpZ_bbuwWuRuGfPdTF2z0SfBgy7YAT4IyCiVqrQ]aptn95@d...[/url
> Sent: Tuesday, March 23, 2004 1:57 PM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative? For Basic
> stamp2
>
>
> Hi folks,
>
> Im working on a project that involves measuring the movement of
> pendulums, on one axis only. I had initially intended using
> accelerometerss placed in the weight of the pendulum to give me the
> information I need to give a continuously changing value that
> indicated the amount of "swing" in one axis only.
>
> The weights are suspended on fishing line, though the cabling
> necessary for the accelerometer would be fed up the line as well. I
> envisage the weights and length of line suspending the pendulums to
> be great enough such that the cabling wont affect movement in any way
> great enough to cause me problems...
>
> Now, the real problem is, these Memsic Accelerometer devices are
> quite expensive. I envisage having up to about 8 pendulums of
> differing lengths
> [url=etc....http://www.hvwtech.com/pages/products_view.asp?ProductID=373]etc....http://www.hvwtech.com/pages/products_view.asp?ProductID=373[/url]
>
> They seem ideal really.....
>
> Could anyone here suggest a cheaper, yest effective way of me being
> able to measure the extent of the swing of the pendulum in one axis
> only? It would have to be something that didnt impact the swing of
> the weights too much, if at all.
>
> Has anyone done something similar?
>
> Any suggestions at all would be gratefully received...
>
> Many thanks
>
>
> Alan
>
>
> 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.
>
> Yahoo! Groups Links
>
>
>
>
>
>
I was able to order mine as engineering samples.
Steve, it's not a mechanical device, like the things worn by the crash
test dummies, its an electronic device, using the MEMS process.
In fact, contrary to the other companies which advertise in the trade
magazines, they were the first. I've trying to get their gyroscope
chips from them, which were made using the same process, but those are
expensive.
Gregg C Levine hansolofalcon@w...
"The Force will be with you...Always." Obi-Wan Kenobi
"Use the Force, Luke."· Obi-Wan Kenobi
>
Original Message
> From: SB [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=7Xr8_5bj_5-lgI5hMjf2_oJWAKuF-pJ9pjOq_qDhYAlVfaG38nouplbvnvrIxb41yEJf_yY2KxCYjb1q39A]steve.brady@r...[/url
> Sent: Tuesday, March 23, 2004 4:34 PM
> To: basicstamps@yahoogroups.com
> Subject: Re: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative? For
Basic stamp2
>
> Analog Devices sells accelerometers!
>
> Retails out of digikey and probably electrosonic too!
> I just picked up the ADXL210AE for like $30 shipping and all. I
didn't
> think that was too much.
> But this IS a mechanical device as opposed to memsics moving bubble
method!
>
>
Original Message
> From: "advice_sought" <aptn95@d...>
> To: <basicstamps@yahoogroups.com>
> Sent: Tuesday, March 23, 2004 2:57 PM
> Subject: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative? For
Basic stamp2
>
>
> > Hi folks,
> >
> > Im working on a project that involves measuring the movement of
> > pendulums, on one axis only. I had initially intended using
> > accelerometerss placed in the weight of the pendulum to give me
the
> > information I need to give a continuously changing value that
> > indicated the amount of "swing" in one axis only.
> >
> > The weights are suspended on fishing line, though the cabling
> > necessary for the accelerometer would be fed up the line as well.
I
> > envisage the weights and length of line suspending the pendulums
to
> > be great enough such that the cabling wont affect movement in any
way
> > great enough to cause me problems...
> >
> > Now, the real problem is, these Memsic Accelerometer devices are
> > quite expensive. I envisage having up to about 8 pendulums of
> > differing lengths
> >
[url=etc....http://www.hvwtech.com/pages/products_view.asp?ProductID=373]etc....http://www.hvwtech.com/pages/products_view.asp?ProductID=373[/url]
> >
> > They seem ideal really.....
> >
> > Could anyone here suggest a cheaper, yest effective way of me
being
> > able to measure the extent of the swing of the pendulum in one
axis
> > only? It would have to be something that didnt impact the swing of
> > the weights too much, if at all.
> >
> > Has anyone done something similar?
> >
> > Any suggestions at all would be gratefully received...
> >
> > Many thanks
> >
> >
> > Alan
Sounds mechanical to me!! I hate to say it...but if it says mechanical in
it....I figure it's mechanical!!
The memsic ones use a heater and traveling bubble (for lack of a better
word)....so they advertise no moving parts.
There's no rotor or anything on the ADXL's but it sounds like a strain guage
to me.
But you're right that it's not like the dummies use. Those are much more
sturdy and probably have a higher resolution.
Original Message
From: "Gregg C Levine" <hansolofalcon@w...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, March 23, 2004 7:24 PM
Subject: RE: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative? For Basic
stamp2
Hello from Gregg C Levine
I was able to order mine as engineering samples.
Steve, it's not a mechanical device, like the things worn by the crash
test dummies, its an electronic device, using the MEMS process.
In fact, contrary to the other companies which advertise in the trade
magazines, they were the first. I've trying to get their gyroscope
chips from them, which were made using the same process, but those are
expensive.
Gregg C Levine hansolofalcon@w...
"The Force will be with you...Always." Obi-Wan Kenobi
"Use the Force, Luke." Obi-Wan Kenobi
>
Original Message
> From: SB [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=_ZIf3NX2IgNSL4J0kfUimSYZOggjNnNlFdMVAUHNviA1-YFOl9D9zUOc_hZZxo66kUUlIzpF0zJe78KeEOXx6Q]steve.brady@r...[/url
> Sent: Tuesday, March 23, 2004 4:34 PM
> To: basicstamps@yahoogroups.com
> Subject: Re: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative? For
Basic stamp2
>
> Analog Devices sells accelerometers!
>
> Retails out of digikey and probably electrosonic too!
> I just picked up the ADXL210AE for like $30 shipping and all. I
didn't
> think that was too much.
> But this IS a mechanical device as opposed to memsics moving bubble
method!
>
>
Original Message
> From: "advice_sought" <aptn95@d...>
> To: <basicstamps@yahoogroups.com>
> Sent: Tuesday, March 23, 2004 2:57 PM
> Subject: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative? For
Basic stamp2
>
>
> > Hi folks,
> >
> > Im working on a project that involves measuring the movement of
> > pendulums, on one axis only. I had initially intended using
> > accelerometerss placed in the weight of the pendulum to give me
the
> > information I need to give a continuously changing value that
> > indicated the amount of "swing" in one axis only.
> >
> > The weights are suspended on fishing line, though the cabling
> > necessary for the accelerometer would be fed up the line as well.
I
> > envisage the weights and length of line suspending the pendulums
to
> > be great enough such that the cabling wont affect movement in any
way
> > great enough to cause me problems...
> >
> > Now, the real problem is, these Memsic Accelerometer devices are
> > quite expensive. I envisage having up to about 8 pendulums of
> > differing lengths
> >
[url=etc....http://www.hvwtech.com/pages/products_view.asp?ProductID=373]etc....http://www.hvwtech.com/pages/products_view.asp?ProductID=373[/url]
> >
> > They seem ideal really.....
> >
> > Could anyone here suggest a cheaper, yest effective way of me
being
> > able to measure the extent of the swing of the pendulum in one
axis
> > only? It would have to be something that didnt impact the swing of
> > the weights too much, if at all.
> >
> > Has anyone done something similar?
> >
> > Any suggestions at all would be gratefully received...
> >
> > Many thanks
> >
> >
> > Alan
To UNSUBSCRIBE, just send mail to:
basicstamps-unsubscribe@yahoogroups.com
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Yahoo! Groups Links
Your close. Very close. According to the bright guys at Analog, their
implementation of the accelerometer design, using the MEMS technology,
is actually better then the ones that are used inside the crash
dummies. In fact those chips are even being used in the aircraft, and
spacecraft market. That is, those that can survive the shocks
generated at those speeds.
In fact the MEMS design, according to an article on them, in Sensors
magazine, a few months ago, stated that they were better then the
Memsic designs. Yours are based on technology that was invented some
forty years ago. For my money, I'd use the Analog components.
In fact somewhere on the Parallax website is an excellent article on
using one with a Stamp2 device.
Jon, care to comment on that?
Gregg C Levine hansolofalcon@w...
"The Force will be with you...Always." Obi-Wan Kenobi
"Use the Force, Luke."· Obi-Wan Kenobi
>
Original Message
> From: SB [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=hA7j_0CYGcuLcsDk8xFwRj02HZwSAsPaE6CPRG_pCGoJOX9gaTRg4Jv3Lo9XqlnFh8suiKC6jGtp8ymO]steve.brady@r...[/url
> Sent: Tuesday, March 23, 2004 9:42 PM
> To: basicstamps@yahoogroups.com
> Subject: Re: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative? For
Basic stamp2
>
> The Analog Device XL brands use a micro electro mechanical system
(MEMS).
> Sounds mechanical to me!! I hate to say it...but if it says
mechanical in
> it....I figure it's mechanical!!
>
> The memsic ones use a heater and traveling bubble (for lack of a
better
> word)....so they advertise no moving parts.
> There's no rotor or anything on the ADXL's but it sounds like a
strain guage
> to me.
>
> But you're right that it's not like the dummies use. Those are much
more
> sturdy and probably have a higher resolution.
>
>
>
>
Original Message
> From: "Gregg C Levine" <hansolofalcon@w...>
> To: <basicstamps@yahoogroups.com>
> Sent: Tuesday, March 23, 2004 7:24 PM
> Subject: RE: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative? For
Basic
> stamp2
>
>
> Hello from Gregg C Levine
> I was able to order mine as engineering samples.
> Steve, it's not a mechanical device, like the things worn by the
crash
> test dummies, its an electronic device, using the MEMS process.
>
> In fact, contrary to the other companies which advertise in the
trade
> magazines, they were the first. I've trying to get their gyroscope
> chips from them, which were made using the same process, but those
are
> expensive.
>
> Gregg C Levine hansolofalcon@w...
>
> "The Force will be with you...Always." Obi-Wan Kenobi
> "Use the Force, Luke." Obi-Wan Kenobi
>
> >
Original Message
> > From: SB [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=hA7j_0CYGcuLcsDk8xFwRj02HZwSAsPaE6CPRG_pCGoJOX9gaTRg4Jv3Lo9XqlnFh8suiKC6jGtp8ymO]steve.brady@r...[/url
> > Sent: Tuesday, March 23, 2004 4:34 PM
> > To: basicstamps@yahoogroups.com
> > Subject: Re: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative?
For
> Basic stamp2
> >
> > Analog Devices sells accelerometers!
> >
> > Retails out of digikey and probably electrosonic too!
> > I just picked up the ADXL210AE for like $30 shipping and all. I
> didn't
> > think that was too much.
> > But this IS a mechanical device as opposed to memsics moving
bubble
> method!
> >
> >
Original Message
> > From: "advice_sought" <aptn95@d...>
> > To: <basicstamps@yahoogroups.com>
> > Sent: Tuesday, March 23, 2004 2:57 PM
> > Subject: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative? For
> Basic stamp2
> >
> >
> > > Hi folks,
> > >
> > > Im working on a project that involves measuring the movement of
> > > pendulums, on one axis only. I had initially intended using
> > > accelerometerss placed in the weight of the pendulum to give me
> the
> > > information I need to give a continuously changing value that
> > > indicated the amount of "swing" in one axis only.
> > >
> > > The weights are suspended on fishing line, though the cabling
> > > necessary for the accelerometer would be fed up the line as
well.
> I
> > > envisage the weights and length of line suspending the pendulums
> to
> > > be great enough such that the cabling wont affect movement in
any
> way
> > > great enough to cause me problems...
> > >
> > > Now, the real problem is, these Memsic Accelerometer devices are
> > > quite expensive. I envisage having up to about 8 pendulums of
> > > differing lengths
> > >
> [url=etc....http://www.hvwtech.com/pages/products_view.asp?ProductID=373]etc....http://www.hvwtech.com/pages/products_view.asp?ProductID=373[/url]
> > >
> > > They seem ideal really.....
> > >
> > > Could anyone here suggest a cheaper, yest effective way of me
> being
> > > able to measure the extent of the swing of the pendulum in one
> axis
> > > only? It would have to be something that didnt impact the swing
of
> > > the weights too much, if at all.
> > >
> > > Has anyone done something similar?
> > >
> > > Any suggestions at all would be gratefully received...
> > >
> > > Many thanks
> > >
> > >
> > > Alan
>
>
>
> 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.
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
> 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.
>
> Yahoo! Groups Links
>
>
>
>
weapons!!
I'll post my final code! We've got the chip...but it's surface mount
(PLCC?? or a PGA) it's only 6 pins though so shouldn't be too bad. We order
the evaluation board too. We should see the board tomorrow or by the end of
the week.
Been using a pulse generator to get my code going.
It's nice using the 0.5mS period, so with the BS2's pulsin resolution (2uS)
you get 250 counts. Which means it fits in to a Byte instead of wasting a
Word (did I get that right?)
Anyhow...I'll post it when it works!
Cheers
SB
Original Message
From: "Gregg C Levine" <hansolofalcon@w...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, March 24, 2004 1:53 AM
Subject: RE: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative? For Basic
stamp2
Hello (again) from Gregg C Levine
Your close. Very close. According to the bright guys at Analog, their
implementation of the accelerometer design, using the MEMS technology,
is actually better then the ones that are used inside the crash
dummies. In fact those chips are even being used in the aircraft, and
spacecraft market. That is, those that can survive the shocks
generated at those speeds.
In fact the MEMS design, according to an article on them, in Sensors
magazine, a few months ago, stated that they were better then the
Memsic designs. Yours are based on technology that was invented some
forty years ago. For my money, I'd use the Analog components.
In fact somewhere on the Parallax website is an excellent article on
using one with a Stamp2 device.
Jon, care to comment on that?
Gregg C Levine hansolofalcon@w...
"The Force will be with you...Always." Obi-Wan Kenobi
"Use the Force, Luke." Obi-Wan Kenobi
>
Original Message
> From: SB [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=booaHWKboCAjdKsSVkj3XnuQ5smyZ4wSRhJC1fDviE7KiZh5J2TJPaSlCI_VycJZdtqLldI0b66Owqpnrw]steve.brady@r...[/url
> Sent: Tuesday, March 23, 2004 9:42 PM
> To: basicstamps@yahoogroups.com
> Subject: Re: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative? For
Basic stamp2
>
> The Analog Device XL brands use a micro electro mechanical system
(MEMS).
> Sounds mechanical to me!! I hate to say it...but if it says
mechanical in
> it....I figure it's mechanical!!
>
> The memsic ones use a heater and traveling bubble (for lack of a
better
> word)....so they advertise no moving parts.
> There's no rotor or anything on the ADXL's but it sounds like a
strain guage
> to me.
>
> But you're right that it's not like the dummies use. Those are much
more
> sturdy and probably have a higher resolution.
>
>
>
>
Original Message
> From: "Gregg C Levine" <hansolofalcon@w...>
> To: <basicstamps@yahoogroups.com>
> Sent: Tuesday, March 23, 2004 7:24 PM
> Subject: RE: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative? For
Basic
> stamp2
>
>
> Hello from Gregg C Levine
> I was able to order mine as engineering samples.
> Steve, it's not a mechanical device, like the things worn by the
crash
> test dummies, its an electronic device, using the MEMS process.
>
> In fact, contrary to the other companies which advertise in the
trade
> magazines, they were the first. I've trying to get their gyroscope
> chips from them, which were made using the same process, but those
are
> expensive.
>
> Gregg C Levine hansolofalcon@w...
>
> "The Force will be with you...Always." Obi-Wan Kenobi
> "Use the Force, Luke." Obi-Wan Kenobi
>
> >
Original Message
> > From: SB [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=booaHWKboCAjdKsSVkj3XnuQ5smyZ4wSRhJC1fDviE7KiZh5J2TJPaSlCI_VycJZdtqLldI0b66Owqpnrw]steve.brady@r...[/url
> > Sent: Tuesday, March 23, 2004 4:34 PM
> > To: basicstamps@yahoogroups.com
> > Subject: Re: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative?
For
> Basic stamp2
> >
> > Analog Devices sells accelerometers!
> >
> > Retails out of digikey and probably electrosonic too!
> > I just picked up the ADXL210AE for like $30 shipping and all. I
> didn't
> > think that was too much.
> > But this IS a mechanical device as opposed to memsics moving
bubble
> method!
> >
> >
Original Message
> > From: "advice_sought" <aptn95@d...>
> > To: <basicstamps@yahoogroups.com>
> > Sent: Tuesday, March 23, 2004 2:57 PM
> > Subject: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative? For
> Basic stamp2
> >
> >
> > > Hi folks,
> > >
> > > Im working on a project that involves measuring the movement of
> > > pendulums, on one axis only. I had initially intended using
> > > accelerometerss placed in the weight of the pendulum to give me
> the
> > > information I need to give a continuously changing value that
> > > indicated the amount of "swing" in one axis only.
> > >
> > > The weights are suspended on fishing line, though the cabling
> > > necessary for the accelerometer would be fed up the line as
well.
> I
> > > envisage the weights and length of line suspending the pendulums
> to
> > > be great enough such that the cabling wont affect movement in
any
> way
> > > great enough to cause me problems...
> > >
> > > Now, the real problem is, these Memsic Accelerometer devices are
> > > quite expensive. I envisage having up to about 8 pendulums of
> > > differing lengths
> > >
> [url=etc....http://www.hvwtech.com/pages/products_view.asp?ProductID=373]etc....http://www.hvwtech.com/pages/products_view.asp?ProductID=373[/url]
> > >
> > > They seem ideal really.....
> > >
> > > Could anyone here suggest a cheaper, yest effective way of me
> being
> > > able to measure the extent of the swing of the pendulum in one
> axis
> > > only? It would have to be something that didnt impact the swing
of
> > > the weights too much, if at all.
> > >
> > > Has anyone done something similar?
> > >
> > > Any suggestions at all would be gratefully received...
> > >
> > > Many thanks
> > >
> > >
> > > Alan
>
>
>
> To UNSUBSCRIBE, just send mail to:
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>
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>
>
>
>
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Yahoo! Groups Links
You forgot, phasers, and photon torpedoes, and proton torpedoes, and
blasters. The first two, are of course Star Trek, the second are Star
Wars.
But that's good news. And while your at it, post a digital photo of it
someplace.
Gregg C Levine hansolofalcon@w...
"The Force will be with you...Always." Obi-Wan Kenobi
"Use the Force, Luke."· Obi-Wan Kenobi
>
Original Message
> From: SB [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Co1AV1vPUiWOCwdUr8xzi8vuSW2M8kyA0ezS69EEyyW7u0gM6C-xD52bP_NrLJwPsORxrL-L32roJpTFeZ8]steve.brady@r...[/url
> Sent: Wednesday, March 24, 2004 6:57 AM
> To: basicstamps@yahoogroups.com
> Subject: Re: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative? For
Basic stamp2
>
> Ha...close works for drive-in and horseshoes...oh and low yield
nuclear
> weapons!!
>
> I'll post my final code! We've got the chip...but it's surface
mount
> (PLCC?? or a PGA) it's only 6 pins though so shouldn't be too bad.
We order
> the evaluation board too. We should see the board tomorrow or by
the end of
> the week.
>
> Been using a pulse generator to get my code going.
> It's nice using the 0.5mS period, so with the BS2's pulsin
resolution (2uS)
> you get 250 counts. Which means it fits in to a Byte instead of
wasting a
> Word (did I get that right?)
>
> Anyhow...I'll post it when it works!
> Cheers
> SB
>
>
Original Message
> From: "Gregg C Levine" <hansolofalcon@w...>
> To: <basicstamps@yahoogroups.com>
> Sent: Wednesday, March 24, 2004 1:53 AM
> Subject: RE: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative? For
Basic
> stamp2
>
>
> Hello (again) from Gregg C Levine
> Your close. Very close. According to the bright guys at Analog,
their
> implementation of the accelerometer design, using the MEMS
technology,
> is actually better then the ones that are used inside the crash
> dummies. In fact those chips are even being used in the aircraft,
and
> spacecraft market. That is, those that can survive the shocks
> generated at those speeds.
>
> In fact the MEMS design, according to an article on them, in Sensors
> magazine, a few months ago, stated that they were better then the
> Memsic designs. Yours are based on technology that was invented some
> forty years ago. For my money, I'd use the Analog components.
>
> In fact somewhere on the Parallax website is an excellent article on
> using one with a Stamp2 device.
>
> Jon, care to comment on that?
>
> Gregg C Levine hansolofalcon@w...
>
> "The Force will be with you...Always." Obi-Wan Kenobi
> "Use the Force, Luke." Obi-Wan Kenobi
>
> >
Original Message
> > From: SB [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Co1AV1vPUiWOCwdUr8xzi8vuSW2M8kyA0ezS69EEyyW7u0gM6C-xD52bP_NrLJwPsORxrL-L32roJpTFeZ8]steve.brady@r...[/url
> > Sent: Tuesday, March 23, 2004 9:42 PM
> > To: basicstamps@yahoogroups.com
> > Subject: Re: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative?
For
> Basic stamp2
> >
> > The Analog Device XL brands use a micro electro mechanical system
> (MEMS).
> > Sounds mechanical to me!! I hate to say it...but if it says
> mechanical in
> > it....I figure it's mechanical!!
> >
> > The memsic ones use a heater and traveling bubble (for lack of a
> better
> > word)....so they advertise no moving parts.
> > There's no rotor or anything on the ADXL's but it sounds like a
> strain guage
> > to me.
> >
> > But you're right that it's not like the dummies use. Those are
much
> more
> > sturdy and probably have a higher resolution.
> >
> >
> >
> >
Original Message
> > From: "Gregg C Levine" <hansolofalcon@w...>
> > To: <basicstamps@yahoogroups.com>
> > Sent: Tuesday, March 23, 2004 7:24 PM
> > Subject: RE: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative?
For
> Basic
> > stamp2
> >
> >
> > Hello from Gregg C Levine
> > I was able to order mine as engineering samples.
> > Steve, it's not a mechanical device, like the things worn by the
> crash
> > test dummies, its an electronic device, using the MEMS process.
> >
> > In fact, contrary to the other companies which advertise in the
> trade
> > magazines, they were the first. I've trying to get their gyroscope
> > chips from them, which were made using the same process, but those
> are
> > expensive.
> >
> > Gregg C Levine hansolofalcon@w...
> >
> > "The Force will be with you...Always." Obi-Wan Kenobi
> > "Use the Force, Luke." Obi-Wan Kenobi
> >
> > >
Original Message
> > > From: SB [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Co1AV1vPUiWOCwdUr8xzi8vuSW2M8kyA0ezS69EEyyW7u0gM6C-xD52bP_NrLJwPsORxrL-L32roJpTFeZ8]steve.brady@r...[/url
> > > Sent: Tuesday, March 23, 2004 4:34 PM
> > > To: basicstamps@yahoogroups.com
> > > Subject: Re: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative?
> For
> > Basic stamp2
> > >
> > > Analog Devices sells accelerometers!
> > >
> > > Retails out of digikey and probably electrosonic too!
> > > I just picked up the ADXL210AE for like $30 shipping and all. I
> > didn't
> > > think that was too much.
> > > But this IS a mechanical device as opposed to memsics moving
> bubble
> > method!
> > >
> > >
Original Message
> > > From: "advice_sought" <aptn95@d...>
> > > To: <basicstamps@yahoogroups.com>
> > > Sent: Tuesday, March 23, 2004 2:57 PM
> > > Subject: [noparse][[/noparse]basicstamps] pendulum, accelerometer alternative? For
> > Basic stamp2
> > >
> > >
> > > > Hi folks,
> > > >
> > > > Im working on a project that involves measuring the movement
of
> > > > pendulums, on one axis only. I had initially intended using
> > > > accelerometerss placed in the weight of the pendulum to give
me
> > the
> > > > information I need to give a continuously changing value that
> > > > indicated the amount of "swing" in one axis only.
> > > >
> > > > The weights are suspended on fishing line, though the cabling
> > > > necessary for the accelerometer would be fed up the line as
> well.
> > I
> > > > envisage the weights and length of line suspending the
pendulums
> > to
> > > > be great enough such that the cabling wont affect movement in
> any
> > way
> > > > great enough to cause me problems...
> > > >
> > > > Now, the real problem is, these Memsic Accelerometer devices
are
> > > > quite expensive. I envisage having up to about 8 pendulums of
> > > > differing lengths
> > > >
> >
[url=etc....http://www.hvwtech.com/pages/products_view.asp?ProductID=373]etc....http://www.hvwtech.com/pages/products_view.asp?ProductID=373[/url]
> > > >
> > > > They seem ideal really.....
> > > >
> > > > Could anyone here suggest a cheaper, yest effective way of me
> > being
> > > > able to measure the extent of the swing of the pendulum in one
> > axis
> > > > only? It would have to be something that didnt impact the
swing
> of
> > > > the weights too much, if at all.
> > > >
> > > > Has anyone done something similar?
> > > >
> > > > Any suggestions at all would be gratefully received...
> > > >
> > > > Many thanks
> > > >
> > > >
> > > > Alan
I have seen several good responses to your request, and perhaps
you have already found a solution. May I offer yet another
approach?
1) If you use two open air coils perpendicular to each other and
inside one another so that if you are looking at them on end
they would form a + in the Zero degree position. Attach one to
the pendulum and the other to the pendulum fixture. Supply a
sine wave to one coil (doesn't matter which one) and monitor
the voltage magnitude produced on the second coil as well as
the phase between coils to determine direction and degree.
2) Use three open air coils positioned to form OOO. Wire the outer
two coils so that they are reverse biased and use these as your
input signal (sine wave) monitor the voltage magnitude produced
on the center coil as well as the phase between the signal going
to the outer coils to determine direction and degree. Near the
pendulum position the coils so that the center coil is in alignment
with the pendulum when it is at rest. On the pendulum attach a
metal slug (nail) so that it is horizontal to the ground.
<--- ######Iron###### --->
o--((Coil1((--o o--((Coil2((--o o--((Coil3((--o
| | | | | |
| o
o |
Signal In | | Signal In
| |
Signal Out Signal Out
>Hi folks,
>
>Im working on a project that involves measuring the movement of
>pendulums, on one axis only. I had initially intended using
>accelerometerss placed in the weight of the pendulum to give me the
>information I need to give a continuously changing value that
>indicated the amount of "swing" in one axis only.
>
>The weights are suspended on fishing line, though the cabling
>necessary for the accelerometer would be fed up the line as well. I
>envisage the weights and length of line suspending the pendulums to
>be great enough such that the cabling wont affect movement in any way
>great enough to cause me problems...
>
>Now, the real problem is, these Memsic Accelerometer devices are
>quite expensive. I envisage having up to about 8 pendulums of
>differing lengths
>[url=etc....http://www.hvwtech.com/pages/products_view.asp?ProductID=373]etc....http://www.hvwtech.com/pages/products_view.asp?ProductID=373[/url]
>
>They seem ideal really.....
>
>Could anyone here suggest a cheaper, yest effective way of me being
>able to measure the extent of the swing of the pendulum in one axis
>only? It would have to be something that didnt impact the swing of
>the weights too much, if at all.
>
>Has anyone done something similar?
>
>Any suggestions at all would be gratefully received...
>
>Many thanks
>
>
>Alan
>
Beau Schwabe Mask Designer National Semiconductor Corporation
500 Pinnacle Court, Suite 525
Home: polygon_man@h... Mail Stop GA1
Work: bschwabe@a... Norcross, GA 30071