I understand that it only detects changes in speed, but how sensitive is it?
My robot will be taking .5-1" steps every few seconds using a worm gear
drive.
> Date: Thu, 22 Nov 2001 21:05:36 -0500 (EST)
> From: carl@g...
> Subject: Re: Accelerometer
>
> Only a change in speed or direction would be registered. Once it is
moving,
> at speed everything becomes steady-state. Think about floating in a canoe
> down a peaceful river with your eyes closed. Can you tell that you're
moving?
Carl,
How small is small? I used the Innovation FIRST accelerometer during
a robotics competition to measure rotational speed, however I don't
think this is what your looking for. It looks like it was an adapted
automotive sensor and is about 3" X 3". There is a sensor from A that
measures linear acceleration thats about the size of quarter. You can
check the datasheet for response time and sensitivity if it's size is
appropriate. Part #ADXL202. A is located in Norwood, Massachussetts
on Technology Way or check the Parallax website for the kit.
--- In basicstamps@y..., carl@g... wrote:
> >If you strap an accelerometer to the back of a snail on a
leisurely stroll,
> will it read anything? What I'm asking is how sensitive are these
devices?
> Is there a minimum acceleration rate before it starts detecting
motion?
> >
> >I'm working on an application where I need to know if a slow-
moving robot
> has gotten stuck (i.e. no acceleration when motors are turning).
It has to
> be a small solution because the robot I'm building is going to be
used to
> explore some very cramped spaces.
> >
>
> Only a change in speed or direction would be registered. Once it
is moving,
> at speed everything becomes steady-state. Think about floating in
a canoe
> down a peaceful river with your eyes closed. Can you tell that
you're moving?
Mentioned often on this list is Analog Devices ADXL202, 2-axis
accelerometer chip. The spec sheet says 5 milli-g resolution. That's
sensitive enough for your application, because any practical robot will
generate pulses of acceleration/deceleration during motion. This device
is readily interfaced to a Stamp or PIC, and costs around $20. See the
mfr's application notes for very helpful information.
If you strap an accelerometer to the back of a snail on a leisurely
stroll, will it read anything? What I'm asking is how sensitive are
these devices? Is there a minimum acceleration rate before it starts
detecting motion?
I'm working on an application where I need to know if a slow-moving
robot has gotten stuck (i.e. no acceleration when motors are turning).
It has to be a small solution because the robot I'm building is going to
be used to explore some very cramped spaces.
Thanks,
Barry
[noparse][[/noparse]Non-text portions of this message have been removed]
To UNSUBSCRIBE, just send mail to: basicstamps-unsubscribe@yahoogroups.com
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>Carl,
>How small is small? I used the Innovation FIRST accelerometer during
>a robotics competition to measure rotational speed, however I don't
>think this is what your looking for. It looks like it was an adapted
I don't have any knowlege of accelerometers. I wanted to be certain
that you realized that once the robot reaches cruising speed that accer-
ation stops, even though the robot is still moving.
Get the ADXL202 Evaluation Board part number ADXL202EB. It's only $29.95
and it makes using it a piece of cake as the connections come out to a 5-pin
header. Trust me... it's worth it to not have to solder leads to the micro
SMT part!
Email me if you'd like a copy of the ADXL202 BS2 code I use on my robots. I
hope this helps.
Regards,
Brice D. Hornback
Clisby Miniature Machines - USA
(miniature vertical milling machines and lathes) http://www.cyberbound.net/clisby
Original Message
From: "thekoookooo" <thekoookooo@y...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, September 18, 2002 12:47 PM
Subject: [noparse][[/noparse]basicstamps] Accelerometer
> Hi,
>
> I'm looking for a low cost accelerometer, in order to interface it to
> my basic stamp. I have found the ADXL202 from analog devices, but I
> don't know it is the best solution. If anyone have worked with those
> kind of chips, I would be glad to hear from you.
>
> Thanks a lot.
I'll second that ! I have the Eval board and it works great. What amazes
me about the device is how stable the output is. I was expecting output
only during a CHANGE in attitude but it's output is proportional to the
angle of the device as long as the device is displaced from the reference
plane, PERFECT for my application.. (depth/pitch control in a R/C submarine)
A great device and great price on the eval board.
Mike B.
Original Message
From: "Brice D. Hornback" <bdh@c...>
To: <basicstamps@yahoogroups.com>
Sent: Sunday, September 22, 2002 7:55 AM
Subject: Re: [noparse][[/noparse]basicstamps] Accelerometer
> Get the ADXL202 Evaluation Board part number ADXL202EB. It's only $29.95
> and it makes using it a piece of cake as the connections come out to a
5-pin
> header. Trust me... it's worth it to not have to solder leads to the
micro
> SMT part!
>
> Download the datasheet. Here's a link:
> http://products.analog.com/products/info.asp?product=ADXL202
>
> Also, here is an application note (includes sample code) on using the
> ADXL202 with a Basic Stamp:
> http://www.analog.com/library/applicationNotes/mems/AN596.pdf
>
> Email me if you'd like a copy of the ADXL202 BS2 code I use on my robots.
I
> hope this helps.
>
> Regards,
>
> Brice D. Hornback
> Clisby Miniature Machines - USA
> (miniature vertical milling machines and lathes)
> http://www.cyberbound.net/clisby
>
>
>
Original Message
> From: "thekoookooo" <thekoookooo@y...>
> To: <basicstamps@yahoogroups.com>
> Sent: Wednesday, September 18, 2002 12:47 PM
> Subject: [noparse][[/noparse]basicstamps] Accelerometer
>
>
> > Hi,
> >
> > I'm looking for a low cost accelerometer, in order to interface it to
> > my basic stamp. I have found the ADXL202 from analog devices, but I
> > don't know it is the best solution. If anyone have worked with those
> > kind of chips, I would be glad to hear from you.
> >
> > Thanks a lot.
>
>
>
> 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/
>
>
If these are the same ones I'm thinking of, they look like fat SOICs.
Here's a tip: Get a surfboard made for a 14/16 pin SOIC. Rotate the chip
so that pin 1 is "backwards" relative to the board. You'll see that one
row of pins will line up with the pads and the others will almost
perfectly line up with the line pattern on the surfboard. Scrape the
solder mask from the line pattern and solder. You'll notice that two
pins are shorted and one pin is N/C, but they are all N/C pins on the
device anyway (that's why you have to rotate the chip).
>
Original Message
> From: Mike Blier [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Q-8EdwsVc7zmei85NAtSabpBaUk1KhuVNUJpZzYJi7ULrP6e2ojoYUuZFhv_TMvo1gxEFR-ccuiDAn8]w6ffc@p...[/url
> Sent: Sunday, September 22, 2002 10:26 AM
> To: basicstamps@yahoogroups.com
> Subject: Re: [noparse][[/noparse]basicstamps] Accelerometer
>
>
> I'll second that ! I have the Eval board and it works great.
> What amazes me about the device is how stable the output is.
> I was expecting output only during a CHANGE in attitude but
> it's output is proportional to the angle of the device as
> long as the device is displaced from the reference plane,
> PERFECT for my application.. (depth/pitch control in a R/C submarine)
>
> A great device and great price on the eval board.
>
> Mike B.
>
>
Original Message
> From: "Brice D. Hornback" <bdh@c...>
> To: <basicstamps@yahoogroups.com>
> Sent: Sunday, September 22, 2002 7:55 AM
> Subject: Re: [noparse][[/noparse]basicstamps] Accelerometer
>
>
> > Get the ADXL202 Evaluation Board part number ADXL202EB. It's only
> > $29.95 and it makes using it a piece of cake as the
> connections come
> > out to a
> 5-pin
> > header. Trust me... it's worth it to not have to solder
> leads to the
> micro
> > SMT part!
> >
> > Download the datasheet. Here's a link:
> > http://products.analog.com/products/info.asp?product=ADXL202
> >
> > Also, here is an application note (includes sample code) on
> using the
> > ADXL202 with a Basic Stamp:
> > http://www.analog.com/library/applicationNotes/mems/AN596.pdf
> >
> > Email me if you'd like a copy of the ADXL202 BS2 code I use on my
> > robots.
> I
> > hope this helps.
> >
> > Regards,
> >
> > Brice D. Hornback
> > Clisby Miniature Machines - USA
> > (miniature vertical milling machines and lathes)
> > http://www.cyberbound.net/clisby
> >
> >
> >
Original Message
> > From: "thekoookooo" <thekoookooo@y...>
> > To: <basicstamps@yahoogroups.com>
> > Sent: Wednesday, September 18, 2002 12:47 PM
> > Subject: [noparse][[/noparse]basicstamps] Accelerometer
> >
> >
> > > Hi,
> > >
> > > I'm looking for a low cost accelerometer, in order to
> interface it
> > > to my basic stamp. I have found the ADXL202 from analog
> devices, but
> > > I don't know it is the best solution. If anyone have worked with
> > > those kind of chips, I would be glad to hear from you.
> > >
> > > Thanks a lot.
> >
> >
> >
> > 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/
> >
> >
>
>
>
> 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/
Nope... they are a 5 mm x 5 mm x 2 mm 8-lead hermetic LCC package. They are
VERY tiny and almost impossible to solder to. I haven't found a surfboard
that will work. What I have done is solder tiny pieces of wirewrap wire to
the "pins" and soldered that to a 8-pin DIP socket to act as a carrier. Of
course... I did that using a 10X loupe and having the soldering iron that
close to my nose did make me a bit nervous! ;-)
It's the same price direct from Analog Devices... so please support
Parallax, Inc. They've been good to us.
Regards,
Brice D. Hornback
Clisby Miniature Machines - USA
(miniature vertical milling machines and lathes) http://www.cyberbound.net/clisby
Original Message
From: "Al Williams" <alw@a...>
To: <basicstamps@yahoogroups.com>
Sent: Sunday, September 22, 2002 10:40 AM
Subject: RE: [noparse][[/noparse]basicstamps] Accelerometer
>
> If these are the same ones I'm thinking of, they look like fat SOICs.
> Here's a tip: Get a surfboard made for a 14/16 pin SOIC. Rotate the chip
> so that pin 1 is "backwards" relative to the board. You'll see that one
> row of pins will line up with the pads and the others will almost
> perfectly line up with the line pattern on the surfboard. Scrape the
> solder mask from the line pattern and solder. You'll notice that two
> pins are shorted and one pin is N/C, but they are all N/C pins on the
> device anyway (that's why you have to rotate the chip).
>
> Al Williams
> AWC
> * Easy RS-232 Prototyping
> http://www.al-williams.com/awce/rs1.htm
>
>
> >
Original Message
> > From: Mike Blier [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=i_G7f4Bty97-prlA0jre44-fqiclzBVJS2spI0QcdcKtEii3d33eE3Bqr9CylLLKXh86-YA3lg]w6ffc@p...[/url
> > Sent: Sunday, September 22, 2002 10:26 AM
> > To: basicstamps@yahoogroups.com
> > Subject: Re: [noparse][[/noparse]basicstamps] Accelerometer
> >
> >
> > I'll second that ! I have the Eval board and it works great.
> > What amazes me about the device is how stable the output is.
> > I was expecting output only during a CHANGE in attitude but
> > it's output is proportional to the angle of the device as
> > long as the device is displaced from the reference plane,
> > PERFECT for my application.. (depth/pitch control in a R/C submarine)
> >
> > A great device and great price on the eval board.
> >
> > Mike B.
> >
> >
Original Message
> > From: "Brice D. Hornback" <bdh@c...>
> > To: <basicstamps@yahoogroups.com>
> > Sent: Sunday, September 22, 2002 7:55 AM
> > Subject: Re: [noparse][[/noparse]basicstamps] Accelerometer
> >
> >
> > > Get the ADXL202 Evaluation Board part number ADXL202EB. It's only
> > > $29.95 and it makes using it a piece of cake as the
> > connections come
> > > out to a
> > 5-pin
> > > header. Trust me... it's worth it to not have to solder
> > leads to the
> > micro
> > > SMT part!
> > >
> > > Download the datasheet. Here's a link:
> > > http://products.analog.com/products/info.asp?product=ADXL202
> > >
> > > Also, here is an application note (includes sample code) on
> > using the
> > > ADXL202 with a Basic Stamp:
> > > http://www.analog.com/library/applicationNotes/mems/AN596.pdf
> > >
> > > Email me if you'd like a copy of the ADXL202 BS2 code I use on my
> > > robots.
> > I
> > > hope this helps.
> > >
> > > Regards,
> > >
> > > Brice D. Hornback
> > > Clisby Miniature Machines - USA
> > > (miniature vertical milling machines and lathes)
> > > http://www.cyberbound.net/clisby
> > >
> > >
> > >
Original Message
> > > From: "thekoookooo" <thekoookooo@y...>
> > > To: <basicstamps@yahoogroups.com>
> > > Sent: Wednesday, September 18, 2002 12:47 PM
> > > Subject: [noparse][[/noparse]basicstamps] Accelerometer
> > >
> > >
> > > > Hi,
> > > >
> > > > I'm looking for a low cost accelerometer, in order to
> > interface it
> > > > to my basic stamp. I have found the ADXL202 from analog
> > devices, but
> > > > I don't know it is the best solution. If anyone have worked with
> > > > those kind of chips, I would be glad to hear from you.
> > > >
> > > > Thanks a lot.
> > >
> > >
> > >
> > > 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/
> > >
> > >
> >
> >
> >
> > 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/
>
>
>
> 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/
>
>
This is one of our club members with way too much time on his hands.
Original Message
> I'll second that ! I have the Eval board and it works great. What amazes
> me about the device is how stable the output is. I was expecting output
> only during a CHANGE in attitude but it's output is proportional to the
> angle of the device as long as the device is displaced from the reference
> plane, PERFECT for my application.. (depth/pitch control in a R/C
submarine)
>
> A great device and great price on the eval board.
> > Get the ADXL202 Evaluation Board part number ADXL202EB. It's only
$29.95
> > and it makes using it a piece of cake as the connections come out to a
> 5-pin
> > header. Trust me... it's worth it to not have to solder leads to the
> micro
> > SMT part!
> >
> > Download the datasheet. Here's a link:
> > http://products.analog.com/products/info.asp?product=ADXL202
> >
> > Also, here is an application note (includes sample code) on using the
> > ADXL202 with a Basic Stamp:
> > http://www.analog.com/library/applicationNotes/mems/AN596.pdf
> >
> > Email me if you'd like a copy of the ADXL202 BS2 code I use on my
robots.
Nope... they are a 5 mm x 5 mm x 2 mm 8-lead hermetic LCC package. They are
VERY tiny and almost impossible to solder to. I haven't found a surfboard
that will work. What I have done is solder tiny pieces of wirewrap wire to
the "pins" and soldered that to a 8-pin DIP socket to act as a carrier. Of
course... I did that using a 10X loupe and having the soldering iron that
close to my nose did make me a bit nervous! ;-)
It's the same price direct from Analog Devices... so please support
Parallax, Inc. They've been good to us.
Regards,
Brice D. Hornback
Clisby Miniature Machines - USA
(miniature vertical milling machines and lathes) http://www.cyberbound.net/clisby
Original Message
From: "Al Williams" <alw@a...>
To: <basicstamps@yahoogroups.com>
Sent: Sunday, September 22, 2002 10:40 AM
Subject: RE: [noparse][[/noparse]basicstamps] Accelerometer
>
> If these are the same ones I'm thinking of, they look like fat SOICs.
> Here's a tip: Get a surfboard made for a 14/16 pin SOIC. Rotate the chip
> so that pin 1 is "backwards" relative to the board. You'll see that one
> row of pins will line up with the pads and the others will almost
> perfectly line up with the line pattern on the surfboard. Scrape the
> solder mask from the line pattern and solder. You'll notice that two
> pins are shorted and one pin is N/C, but they are all N/C pins on the
> device anyway (that's why you have to rotate the chip).
>
> Al Williams
> AWC
> * Easy RS-232 Prototyping
> http://www.al-williams.com/awce/rs1.htm
>
>
> >
Original Message
> > From: Mike Blier [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=SZpC0EJcVYewzSf4badE_0QJyUkXOVkySW7aHMEs0rUAtAHFf4Rvk3f9RfTLbhwFti78waYS1whsfak]w6ffc@p...[/url
> > Sent: Sunday, September 22, 2002 10:26 AM
> > To: basicstamps@yahoogroups.com
> > Subject: Re: [noparse][[/noparse]basicstamps] Accelerometer
> >
> >
> > I'll second that ! I have the Eval board and it works great.
> > What amazes me about the device is how stable the output is.
> > I was expecting output only during a CHANGE in attitude but
> > it's output is proportional to the angle of the device as
> > long as the device is displaced from the reference plane,
> > PERFECT for my application.. (depth/pitch control in a R/C submarine)
> >
> > A great device and great price on the eval board.
> >
> > Mike B.
> >
> >
Original Message
> > From: "Brice D. Hornback" <bdh@c...>
> > To: <basicstamps@yahoogroups.com>
> > Sent: Sunday, September 22, 2002 7:55 AM
> > Subject: Re: [noparse][[/noparse]basicstamps] Accelerometer
> >
> >
> > > Get the ADXL202 Evaluation Board part number ADXL202EB. It's only
> > > $29.95 and it makes using it a piece of cake as the
> > connections come
> > > out to a
> > 5-pin
> > > header. Trust me... it's worth it to not have to solder
> > leads to the
> > micro
> > > SMT part!
> > >
> > > Download the datasheet. Here's a link:
> > > http://products.analog.com/products/info.asp?product=ADXL202
> > >
> > > Also, here is an application note (includes sample code) on
> > using the
> > > ADXL202 with a Basic Stamp:
> > > http://www.analog.com/library/applicationNotes/mems/AN596.pdf
> > >
> > > Email me if you'd like a copy of the ADXL202 BS2 code I use on my
> > > robots.
> > I
> > > hope this helps.
> > >
> > > Regards,
> > >
> > > Brice D. Hornback
> > > Clisby Miniature Machines - USA
> > > (miniature vertical milling machines and lathes)
> > > http://www.cyberbound.net/clisby
> > >
> > >
> > >
Original Message
> > > From: "thekoookooo" <thekoookooo@y...>
> > > To: <basicstamps@yahoogroups.com>
> > > Sent: Wednesday, September 18, 2002 12:47 PM
> > > Subject: [noparse][[/noparse]basicstamps] Accelerometer
> > >
> > >
> > > > Hi,
> > > >
> > > > I'm looking for a low cost accelerometer, in order to
> > interface it
> > > > to my basic stamp. I have found the ADXL202 from analog
> > devices, but
> > > > I don't know it is the best solution. If anyone have worked with
> > > > those kind of chips, I would be glad to hear from you.
> > > >
> > > > Thanks a lot.
> > >
> > >
> > >
> > > 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/
> > >
> > >
> >
> >
> >
> > 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/
>
>
>
> 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/
>
>
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.
Original Message
From: "Rodent" <daweasel@s...>
To: <basicstamps@yahoogroups.com>
Sent: Sunday, September 22, 2002 9:29 AM
Subject: Re: [noparse][[/noparse]basicstamps] Accelerometer
> Here's a good use for an accelerometer:
>
> http://www.geology.smu.edu/~dpa-www/robo/nbot/index.html
>
> This is one of our club members with way too much time on his hands.
>
>
Original Message
>
> > I'll second that ! I have the Eval board and it works great. What
amazes
> > me about the device is how stable the output is. I was expecting output
> > only during a CHANGE in attitude but it's output is proportional to the
> > angle of the device as long as the device is displaced from the
reference
> > plane, PERFECT for my application.. (depth/pitch control in a R/C
> submarine)
> >
> > A great device and great price on the eval board.
>
> > > Get the ADXL202 Evaluation Board part number ADXL202EB. It's only
> $29.95
> > > and it makes using it a piece of cake as the connections come out to a
> > 5-pin
> > > header. Trust me... it's worth it to not have to solder leads to the
> > micro
> > > SMT part!
> > >
> > > Download the datasheet. Here's a link:
> > > http://products.analog.com/products/info.asp?product=ADXL202
> > >
> > > Also, here is an application note (includes sample code) on using the
> > > ADXL202 with a Basic Stamp:
> > > http://www.analog.com/library/applicationNotes/mems/AN596.pdf
> > >
> > > Email me if you'd like a copy of the ADXL202 BS2 code I use on my
> robots.
>
>
>
>
> 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/
>
>
would one of these devices from Parallex work
correctly as an artificial horizon for a model
aircraft?
I've been investigating solutions involving gyros and
accelerometers, but I thought accelerometers only gave
you rate of change, not the current angle (with
respect to ground plane) at time(t) for example.
Also, do they still work if they are upside down? For
example giving angles > 90 degrees?
thank you
chris
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Actually you would want to use a http://www2.towerhobbies.com/cgi-bin/wti0001p.pgm?Q=1&I=LXNA35&P=7
Autopilot (PA-2 Pilot AssistLink) sensor from Futaba.
This uses the horizon to maintain level flight.
The larger well stocked RC hobby shops also usually have these in stock too.
Accelerometers measure sudden movements from the current reference point.
would one of these devices from Parallex work
correctly as an artificial horizon for a model
aircraft?
I've been investigating solutions involving gyros and
accelerometers, but I thought accelerometers only gave
you rate of change, not the current angle (with
respect to ground plane) at time(t) for example.
Also, do they still work if they are upside down? For
example giving angles > 90 degrees?
thank you
chris
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thanks for the tip Earl. Actually though it isn't an
autopilot/flight leveller i'm looking for. I have a
radio modem on the aircraft sending down telemetry to
a laptop. I'm writing software on the laptop to
display the telemetry. I wanted an artificial horizon
as one of my instruments.
I thought accelerometers only measured sudden
movements as you describe, but it sounds like some
people on the list are getting more of a gyroscopic
type reading (offset from ground/reference plane).
Can anyone confirm/refute this? thank you
chris
--- Earl Bollinger <earlwbollinger@a...> wrote:
> Actually you would want to use a
> http://www2.towerhobbies.com/cgi-bin/wti0001p.pgm?Q=1&I=LXNA35&P=7
> Autopilot (PA-2 Pilot AssistLink) sensor from
> Futaba.
> This uses the horizon to maintain level flight.
> The larger well stocked RC hobby shops also usually
> have these in stock too.
> Accelerometers measure sudden movements from the
> current reference point.
>
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The Futaba horizon unit sends a servo signal that can be measured to
determine how far off from horizon level you are. You can send this signal
back down to the receiving station to feed a horizon indicator meter or
something. For example a 1.5ms pulse width is center(level), 1.6ms is tilt
right, 1.4 ms is tilt left.
The Futaba unit is actually feeding in a correction, so the signal tilt is
actually reversed from normal, as the unit is telling a aileron servo to
level the model plane.
Actually they use a simple potentiometer to measure from ground level.
One way is to have a little tail with the pot at one end and a stick just
touching the floor or ground, as the robot leans forward or back you can
measure the pot to determine how far off you are. But after you get the
formulas and math working you can forgo the pot then. Ultrasound and IR
sensors aren't sensitive enough to small changes.
thanks for the tip Earl. Actually though it isn't an
autopilot/flight leveller i'm looking for. I have a
radio modem on the aircraft sending down telemetry to
a laptop. I'm writing software on the laptop to
display the telemetry. I wanted an artificial horizon
as one of my instruments.
I thought accelerometers only measured sudden
movements as you describe, but it sounds like some
people on the list are getting more of a gyroscopic
type reading (offset from ground/reference plane).
Can anyone confirm/refute this? thank you
chris
--- Earl Bollinger <earlwbollinger@a...> wrote:
> Actually you would want to use a
> http://www2.towerhobbies.com/cgi-bin/wti0001p.pgm?Q=1&I=LXNA35&P=7
> Autopilot (PA-2 Pilot AssistLink) sensor from
> Futaba.
> This uses the horizon to maintain level flight.
> The larger well stocked RC hobby shops also usually
> have these in stock too.
> Accelerometers measure sudden movements from the
> current reference point.
>
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Apparently my earlier reply was missed or mis-read as Earl makes a
incorrect assumption about the ADXL202. It does indeed output a STEADY
pulse width signal in 2 axis WHILE the device is tilted, so yes in that case
it would work as a horizion.
I too was surprised to learn that it didn't JUST respond when a change
was made and then go back to "idle". This mode of operation is referred to
by AD as the "tilt sensor" mode. I am using it in my R/C submarine project
for exactly the purpose of determining the pitch angle of the boat ( to help
control depth while submerged) and will use the other axis (roll) to tell me
(the on board processor that is) if the sub has hit a wave and rolled over
there by letting all the air out of the ballast tanks. (Not good !)
Buy the eval board, you'll love it..
Mike B.
Original Message
From: "chris smith" <chris_smith_inc@y...>
To: <basicstamps@yahoogroups.com>
Sent: Sunday, September 22, 2002 11:07 AM
Subject: [noparse][[/noparse]basicstamps] re: Accelerometer
> would one of these devices from Parallex work
> correctly as an artificial horizon for a model
> aircraft?
>
> I've been investigating solutions involving gyros and
> accelerometers, but I thought accelerometers only gave
> you rate of change, not the current angle (with
> respect to ground plane) at time(t) for example.
> Also, do they still work if they are upside down? For
> example giving angles > 90 degrees?
>
> thank you
>
> chris
>
>
> __________________________________________________
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> New DSL Internet Access from SBC & Yahoo!
> http://sbc.yahoo.com
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
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Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
Thanks Mike! That's exactly what I needed to hear.
:-)
chris
--- Mike Blier <w6ffc@p...> wrote:
> Hi Chris:
>
> Apparently my earlier reply was missed or
> mis-read as Earl makes a
> incorrect assumption about the ADXL202. It does
> indeed output a STEADY
> pulse width signal in 2 axis WHILE the device is
> tilted, so yes in that case
> it would work as a horizion.
>
> I too was surprised to learn that it didn't JUST
> respond when a change
> was made and then go back to "idle". This mode of
> operation is referred to
> by AD as the "tilt sensor" mode. I am using it in
> my R/C submarine project
> for exactly the purpose of determining the pitch
> angle of the boat ( to help
> control depth while submerged) and will use the
> other axis (roll) to tell me
> (the on board processor that is) if the sub has hit
> a wave and rolled over
> there by letting all the air out of the ballast
> tanks. (Not good !)
>
> Buy the eval board, you'll love it..
>
> Mike B.
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New DSL Internet Access from SBC & Yahoo! http://sbc.yahoo.com
Comments
My robot will be taking .5-1" steps every few seconds using a worm gear
drive.
> Date: Thu, 22 Nov 2001 21:05:36 -0500 (EST)
> From: carl@g...
> Subject: Re: Accelerometer
>
> Only a change in speed or direction would be registered. Once it is
moving,
> at speed everything becomes steady-state. Think about floating in a canoe
> down a peaceful river with your eyes closed. Can you tell that you're
moving?
How small is small? I used the Innovation FIRST accelerometer during
a robotics competition to measure rotational speed, however I don't
think this is what your looking for. It looks like it was an adapted
automotive sensor and is about 3" X 3". There is a sensor from A that
measures linear acceleration thats about the size of quarter. You can
check the datasheet for response time and sensitivity if it's size is
appropriate. Part #ADXL202. A is located in Norwood, Massachussetts
on Technology Way or check the Parallax website for the kit.
--- In basicstamps@y..., carl@g... wrote:
> >If you strap an accelerometer to the back of a snail on a
leisurely stroll,
> will it read anything? What I'm asking is how sensitive are these
devices?
> Is there a minimum acceleration rate before it starts detecting
motion?
> >
> >I'm working on an application where I need to know if a slow-
moving robot
> has gotten stuck (i.e. no acceleration when motors are turning).
It has to
> be a small solution because the robot I'm building is going to be
used to
> explore some very cramped spaces.
> >
>
> Only a change in speed or direction would be registered. Once it
is moving,
> at speed everything becomes steady-state. Think about floating in
a canoe
> down a peaceful river with your eyes closed. Can you tell that
you're moving?
accelerometer chip. The spec sheet says 5 milli-g resolution. That's
sensitive enough for your application, because any practical robot will
generate pulses of acceleration/deceleration during motion. This device
is readily interfaced to a Stamp or PIC, and costs around $20. See the
mfr's application notes for very helpful information.
Dennis
Original Message
From: Barry Michels [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=fj538DMMy9hxP4FZUZdEtiCehKrZS3tUayk_gezIKUI6ckJpIeycTX1KZ6sS-M-cwFQQyRI3Tw8]bmichels@e...[/url
Sent: Thursday, November 22, 2001 3:54 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Accelerometer
If you strap an accelerometer to the back of a snail on a leisurely
stroll, will it read anything? What I'm asking is how sensitive are
these devices? Is there a minimum acceleration rate before it starts
detecting motion?
I'm working on an application where I need to know if a slow-moving
robot has gotten stuck (i.e. no acceleration when motors are turning).
It has to be a small solution because the robot I'm building is going to
be used to explore some very cramped spaces.
Thanks,
Barry
[noparse][[/noparse]Non-text portions of this message have been removed]
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>How small is small? I used the Innovation FIRST accelerometer during
>a robotics competition to measure rotational speed, however I don't
>think this is what your looking for. It looks like it was an adapted
I don't have any knowlege of accelerometers. I wanted to be certain
that you realized that once the robot reaches cruising speed that accer-
ation stops, even though the robot is still moving.
and it makes using it a piece of cake as the connections come out to a 5-pin
header. Trust me... it's worth it to not have to solder leads to the micro
SMT part!
Download the datasheet. Here's a link:
http://products.analog.com/products/info.asp?product=ADXL202
Also, here is an application note (includes sample code) on using the
ADXL202 with a Basic Stamp:
http://www.analog.com/library/applicationNotes/mems/AN596.pdf
Email me if you'd like a copy of the ADXL202 BS2 code I use on my robots. I
hope this helps.
Regards,
Brice D. Hornback
Clisby Miniature Machines - USA
(miniature vertical milling machines and lathes)
http://www.cyberbound.net/clisby
Original Message
From: "thekoookooo" <thekoookooo@y...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, September 18, 2002 12:47 PM
Subject: [noparse][[/noparse]basicstamps] Accelerometer
> Hi,
>
> I'm looking for a low cost accelerometer, in order to interface it to
> my basic stamp. I have found the ADXL202 from analog devices, but I
> don't know it is the best solution. If anyone have worked with those
> kind of chips, I would be glad to hear from you.
>
> Thanks a lot.
me about the device is how stable the output is. I was expecting output
only during a CHANGE in attitude but it's output is proportional to the
angle of the device as long as the device is displaced from the reference
plane, PERFECT for my application.. (depth/pitch control in a R/C submarine)
A great device and great price on the eval board.
Mike B.
Original Message
From: "Brice D. Hornback" <bdh@c...>
To: <basicstamps@yahoogroups.com>
Sent: Sunday, September 22, 2002 7:55 AM
Subject: Re: [noparse][[/noparse]basicstamps] Accelerometer
> Get the ADXL202 Evaluation Board part number ADXL202EB. It's only $29.95
> and it makes using it a piece of cake as the connections come out to a
5-pin
> header. Trust me... it's worth it to not have to solder leads to the
micro
> SMT part!
>
> Download the datasheet. Here's a link:
> http://products.analog.com/products/info.asp?product=ADXL202
>
> Also, here is an application note (includes sample code) on using the
> ADXL202 with a Basic Stamp:
> http://www.analog.com/library/applicationNotes/mems/AN596.pdf
>
> Email me if you'd like a copy of the ADXL202 BS2 code I use on my robots.
I
> hope this helps.
>
> Regards,
>
> Brice D. Hornback
> Clisby Miniature Machines - USA
> (miniature vertical milling machines and lathes)
> http://www.cyberbound.net/clisby
>
>
>
Original Message
> From: "thekoookooo" <thekoookooo@y...>
> To: <basicstamps@yahoogroups.com>
> Sent: Wednesday, September 18, 2002 12:47 PM
> Subject: [noparse][[/noparse]basicstamps] Accelerometer
>
>
> > Hi,
> >
> > I'm looking for a low cost accelerometer, in order to interface it to
> > my basic stamp. I have found the ADXL202 from analog devices, but I
> > don't know it is the best solution. If anyone have worked with those
> > kind of chips, I would be glad to hear from you.
> >
> > Thanks a lot.
>
>
>
> 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/
>
>
Here's a tip: Get a surfboard made for a 14/16 pin SOIC. Rotate the chip
so that pin 1 is "backwards" relative to the board. You'll see that one
row of pins will line up with the pads and the others will almost
perfectly line up with the line pattern on the surfboard. Scrape the
solder mask from the line pattern and solder. You'll notice that two
pins are shorted and one pin is N/C, but they are all N/C pins on the
device anyway (that's why you have to rotate the chip).
Al Williams
AWC
* Easy RS-232 Prototyping
http://www.al-williams.com/awce/rs1.htm
>
Original Message
> From: Mike Blier [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Q-8EdwsVc7zmei85NAtSabpBaUk1KhuVNUJpZzYJi7ULrP6e2ojoYUuZFhv_TMvo1gxEFR-ccuiDAn8]w6ffc@p...[/url
> Sent: Sunday, September 22, 2002 10:26 AM
> To: basicstamps@yahoogroups.com
> Subject: Re: [noparse][[/noparse]basicstamps] Accelerometer
>
>
> I'll second that ! I have the Eval board and it works great.
> What amazes me about the device is how stable the output is.
> I was expecting output only during a CHANGE in attitude but
> it's output is proportional to the angle of the device as
> long as the device is displaced from the reference plane,
> PERFECT for my application.. (depth/pitch control in a R/C submarine)
>
> A great device and great price on the eval board.
>
> Mike B.
>
>
Original Message
> From: "Brice D. Hornback" <bdh@c...>
> To: <basicstamps@yahoogroups.com>
> Sent: Sunday, September 22, 2002 7:55 AM
> Subject: Re: [noparse][[/noparse]basicstamps] Accelerometer
>
>
> > Get the ADXL202 Evaluation Board part number ADXL202EB. It's only
> > $29.95 and it makes using it a piece of cake as the
> connections come
> > out to a
> 5-pin
> > header. Trust me... it's worth it to not have to solder
> leads to the
> micro
> > SMT part!
> >
> > Download the datasheet. Here's a link:
> > http://products.analog.com/products/info.asp?product=ADXL202
> >
> > Also, here is an application note (includes sample code) on
> using the
> > ADXL202 with a Basic Stamp:
> > http://www.analog.com/library/applicationNotes/mems/AN596.pdf
> >
> > Email me if you'd like a copy of the ADXL202 BS2 code I use on my
> > robots.
> I
> > hope this helps.
> >
> > Regards,
> >
> > Brice D. Hornback
> > Clisby Miniature Machines - USA
> > (miniature vertical milling machines and lathes)
> > http://www.cyberbound.net/clisby
> >
> >
> >
Original Message
> > From: "thekoookooo" <thekoookooo@y...>
> > To: <basicstamps@yahoogroups.com>
> > Sent: Wednesday, September 18, 2002 12:47 PM
> > Subject: [noparse][[/noparse]basicstamps] Accelerometer
> >
> >
> > > Hi,
> > >
> > > I'm looking for a low cost accelerometer, in order to
> interface it
> > > to my basic stamp. I have found the ADXL202 from analog
> devices, but
> > > I don't know it is the best solution. If anyone have worked with
> > > those kind of chips, I would be glad to hear from you.
> > >
> > > Thanks a lot.
> >
> >
> >
> > 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/
> >
> >
>
>
>
> 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/
VERY tiny and almost impossible to solder to. I haven't found a surfboard
that will work. What I have done is solder tiny pieces of wirewrap wire to
the "pins" and soldered that to a 8-pin DIP socket to act as a carrier. Of
course... I did that using a 10X loupe and having the soldering iron that
close to my nose did make me a bit nervous! ;-)
The eval board is MUCH easier to work with.
Here's a link to the eval board on the Parallax Online store:
http://www.parallaxinc.com/html_files/component_shop/ICs.asp#adxl
It's the same price direct from Analog Devices... so please support
Parallax, Inc. They've been good to us.
Regards,
Brice D. Hornback
Clisby Miniature Machines - USA
(miniature vertical milling machines and lathes)
http://www.cyberbound.net/clisby
Original Message
From: "Al Williams" <alw@a...>
To: <basicstamps@yahoogroups.com>
Sent: Sunday, September 22, 2002 10:40 AM
Subject: RE: [noparse][[/noparse]basicstamps] Accelerometer
>
> If these are the same ones I'm thinking of, they look like fat SOICs.
> Here's a tip: Get a surfboard made for a 14/16 pin SOIC. Rotate the chip
> so that pin 1 is "backwards" relative to the board. You'll see that one
> row of pins will line up with the pads and the others will almost
> perfectly line up with the line pattern on the surfboard. Scrape the
> solder mask from the line pattern and solder. You'll notice that two
> pins are shorted and one pin is N/C, but they are all N/C pins on the
> device anyway (that's why you have to rotate the chip).
>
> Al Williams
> AWC
> * Easy RS-232 Prototyping
> http://www.al-williams.com/awce/rs1.htm
>
>
> >
Original Message
> > From: Mike Blier [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=i_G7f4Bty97-prlA0jre44-fqiclzBVJS2spI0QcdcKtEii3d33eE3Bqr9CylLLKXh86-YA3lg]w6ffc@p...[/url
> > Sent: Sunday, September 22, 2002 10:26 AM
> > To: basicstamps@yahoogroups.com
> > Subject: Re: [noparse][[/noparse]basicstamps] Accelerometer
> >
> >
> > I'll second that ! I have the Eval board and it works great.
> > What amazes me about the device is how stable the output is.
> > I was expecting output only during a CHANGE in attitude but
> > it's output is proportional to the angle of the device as
> > long as the device is displaced from the reference plane,
> > PERFECT for my application.. (depth/pitch control in a R/C submarine)
> >
> > A great device and great price on the eval board.
> >
> > Mike B.
> >
> >
Original Message
> > From: "Brice D. Hornback" <bdh@c...>
> > To: <basicstamps@yahoogroups.com>
> > Sent: Sunday, September 22, 2002 7:55 AM
> > Subject: Re: [noparse][[/noparse]basicstamps] Accelerometer
> >
> >
> > > Get the ADXL202 Evaluation Board part number ADXL202EB. It's only
> > > $29.95 and it makes using it a piece of cake as the
> > connections come
> > > out to a
> > 5-pin
> > > header. Trust me... it's worth it to not have to solder
> > leads to the
> > micro
> > > SMT part!
> > >
> > > Download the datasheet. Here's a link:
> > > http://products.analog.com/products/info.asp?product=ADXL202
> > >
> > > Also, here is an application note (includes sample code) on
> > using the
> > > ADXL202 with a Basic Stamp:
> > > http://www.analog.com/library/applicationNotes/mems/AN596.pdf
> > >
> > > Email me if you'd like a copy of the ADXL202 BS2 code I use on my
> > > robots.
> > I
> > > hope this helps.
> > >
> > > Regards,
> > >
> > > Brice D. Hornback
> > > Clisby Miniature Machines - USA
> > > (miniature vertical milling machines and lathes)
> > > http://www.cyberbound.net/clisby
> > >
> > >
> > >
Original Message
> > > From: "thekoookooo" <thekoookooo@y...>
> > > To: <basicstamps@yahoogroups.com>
> > > Sent: Wednesday, September 18, 2002 12:47 PM
> > > Subject: [noparse][[/noparse]basicstamps] Accelerometer
> > >
> > >
> > > > Hi,
> > > >
> > > > I'm looking for a low cost accelerometer, in order to
> > interface it
> > > > to my basic stamp. I have found the ADXL202 from analog
> > devices, but
> > > > I don't know it is the best solution. If anyone have worked with
> > > > those kind of chips, I would be glad to hear from you.
> > > >
> > > > Thanks a lot.
> > >
> > >
> > >
> > > 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/
> > >
> > >
> >
> >
> >
> > 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/
>
>
>
> To UNSUBSCRIBE, just send mail to:
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>
>
http://www.geology.smu.edu/~dpa-www/robo/nbot/index.html
This is one of our club members with way too much time on his hands.
Original Message
> I'll second that ! I have the Eval board and it works great. What amazes
> me about the device is how stable the output is. I was expecting output
> only during a CHANGE in attitude but it's output is proportional to the
> angle of the device as long as the device is displaced from the reference
> plane, PERFECT for my application.. (depth/pitch control in a R/C
submarine)
>
> A great device and great price on the eval board.
> > Get the ADXL202 Evaluation Board part number ADXL202EB. It's only
$29.95
> > and it makes using it a piece of cake as the connections come out to a
> 5-pin
> > header. Trust me... it's worth it to not have to solder leads to the
> micro
> > SMT part!
> >
> > Download the datasheet. Here's a link:
> > http://products.analog.com/products/info.asp?product=ADXL202
> >
> > Also, here is an application note (includes sample code) on using the
> > ADXL202 with a Basic Stamp:
> > http://www.analog.com/library/applicationNotes/mems/AN596.pdf
> >
> > Email me if you'd like a copy of the ADXL202 BS2 code I use on my
robots.
Devices ADXL202 eval boards. No fuss no mess. You don't have to make a PCB
and solder anything down or get all the right parts.
Try http://www.parallaxinc.com/html_files/component_shop/ICs.asp for more
details.
You can also get if from Analog Devices direct too.
It is pretty popular as they are backordered until the middle of October
sometime.
Original Message
From: Brice D. Hornback [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=r7UQHELmTtocF83CCyfYM6Eu8zKHXbKKZRpppr7FAvscGHm8mmeGW3KHXd_js9jpFyWDwGlwzp5_]bdh@c...[/url
Sent: Sunday, September 22, 2002 10:55 AM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Accelerometer
Nope... they are a 5 mm x 5 mm x 2 mm 8-lead hermetic LCC package. They are
VERY tiny and almost impossible to solder to. I haven't found a surfboard
that will work. What I have done is solder tiny pieces of wirewrap wire to
the "pins" and soldered that to a 8-pin DIP socket to act as a carrier. Of
course... I did that using a 10X loupe and having the soldering iron that
close to my nose did make me a bit nervous! ;-)
The eval board is MUCH easier to work with.
Here's a link to the eval board on the Parallax Online store:
http://www.parallaxinc.com/html_files/component_shop/ICs.asp#adxl
It's the same price direct from Analog Devices... so please support
Parallax, Inc. They've been good to us.
Regards,
Brice D. Hornback
Clisby Miniature Machines - USA
(miniature vertical milling machines and lathes)
http://www.cyberbound.net/clisby
Original Message
From: "Al Williams" <alw@a...>
To: <basicstamps@yahoogroups.com>
Sent: Sunday, September 22, 2002 10:40 AM
Subject: RE: [noparse][[/noparse]basicstamps] Accelerometer
>
> If these are the same ones I'm thinking of, they look like fat SOICs.
> Here's a tip: Get a surfboard made for a 14/16 pin SOIC. Rotate the chip
> so that pin 1 is "backwards" relative to the board. You'll see that one
> row of pins will line up with the pads and the others will almost
> perfectly line up with the line pattern on the surfboard. Scrape the
> solder mask from the line pattern and solder. You'll notice that two
> pins are shorted and one pin is N/C, but they are all N/C pins on the
> device anyway (that's why you have to rotate the chip).
>
> Al Williams
> AWC
> * Easy RS-232 Prototyping
> http://www.al-williams.com/awce/rs1.htm
>
>
> >
Original Message
> > From: Mike Blier [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=SZpC0EJcVYewzSf4badE_0QJyUkXOVkySW7aHMEs0rUAtAHFf4Rvk3f9RfTLbhwFti78waYS1whsfak]w6ffc@p...[/url
> > Sent: Sunday, September 22, 2002 10:26 AM
> > To: basicstamps@yahoogroups.com
> > Subject: Re: [noparse][[/noparse]basicstamps] Accelerometer
> >
> >
> > I'll second that ! I have the Eval board and it works great.
> > What amazes me about the device is how stable the output is.
> > I was expecting output only during a CHANGE in attitude but
> > it's output is proportional to the angle of the device as
> > long as the device is displaced from the reference plane,
> > PERFECT for my application.. (depth/pitch control in a R/C submarine)
> >
> > A great device and great price on the eval board.
> >
> > Mike B.
> >
> >
Original Message
> > From: "Brice D. Hornback" <bdh@c...>
> > To: <basicstamps@yahoogroups.com>
> > Sent: Sunday, September 22, 2002 7:55 AM
> > Subject: Re: [noparse][[/noparse]basicstamps] Accelerometer
> >
> >
> > > Get the ADXL202 Evaluation Board part number ADXL202EB. It's only
> > > $29.95 and it makes using it a piece of cake as the
> > connections come
> > > out to a
> > 5-pin
> > > header. Trust me... it's worth it to not have to solder
> > leads to the
> > micro
> > > SMT part!
> > >
> > > Download the datasheet. Here's a link:
> > > http://products.analog.com/products/info.asp?product=ADXL202
> > >
> > > Also, here is an application note (includes sample code) on
> > using the
> > > ADXL202 with a Basic Stamp:
> > > http://www.analog.com/library/applicationNotes/mems/AN596.pdf
> > >
> > > Email me if you'd like a copy of the ADXL202 BS2 code I use on my
> > > robots.
> > I
> > > hope this helps.
> > >
> > > Regards,
> > >
> > > Brice D. Hornback
> > > Clisby Miniature Machines - USA
> > > (miniature vertical milling machines and lathes)
> > > http://www.cyberbound.net/clisby
> > >
> > >
> > >
Original Message
> > > From: "thekoookooo" <thekoookooo@y...>
> > > To: <basicstamps@yahoogroups.com>
> > > Sent: Wednesday, September 18, 2002 12:47 PM
> > > Subject: [noparse][[/noparse]basicstamps] Accelerometer
> > >
> > >
> > > > Hi,
> > > >
> > > > I'm looking for a low cost accelerometer, in order to
> > interface it
> > > > to my basic stamp. I have found the ADXL202 from analog
> > devices, but
> > > > I don't know it is the best solution. If anyone have worked with
> > > > those kind of chips, I would be glad to hear from you.
> > > >
> > > > Thanks a lot.
> > >
> > >
> > >
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> > Body of the message will be ignored.
> > >
> > >
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> > >
> > >
> >
> >
> >
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>
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Original Message
From: "Rodent" <daweasel@s...>
To: <basicstamps@yahoogroups.com>
Sent: Sunday, September 22, 2002 9:29 AM
Subject: Re: [noparse][[/noparse]basicstamps] Accelerometer
> Here's a good use for an accelerometer:
>
> http://www.geology.smu.edu/~dpa-www/robo/nbot/index.html
>
> This is one of our club members with way too much time on his hands.
>
>
Original Message
>
> > I'll second that ! I have the Eval board and it works great. What
amazes
> > me about the device is how stable the output is. I was expecting output
> > only during a CHANGE in attitude but it's output is proportional to the
> > angle of the device as long as the device is displaced from the
reference
> > plane, PERFECT for my application.. (depth/pitch control in a R/C
> submarine)
> >
> > A great device and great price on the eval board.
>
> > > Get the ADXL202 Evaluation Board part number ADXL202EB. It's only
> $29.95
> > > and it makes using it a piece of cake as the connections come out to a
> > 5-pin
> > > header. Trust me... it's worth it to not have to solder leads to the
> > micro
> > > SMT part!
> > >
> > > Download the datasheet. Here's a link:
> > > http://products.analog.com/products/info.asp?product=ADXL202
> > >
> > > Also, here is an application note (includes sample code) on using the
> > > ADXL202 with a Basic Stamp:
> > > http://www.analog.com/library/applicationNotes/mems/AN596.pdf
> > >
> > > Email me if you'd like a copy of the ADXL202 BS2 code I use on my
> robots.
>
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
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>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
correctly as an artificial horizon for a model
aircraft?
I've been investigating solutions involving gyros and
accelerometers, but I thought accelerometers only gave
you rate of change, not the current angle (with
respect to ground plane) at time(t) for example.
Also, do they still work if they are upside down? For
example giving angles > 90 degrees?
thank you
chris
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http://www2.towerhobbies.com/cgi-bin/wti0001p.pgm?Q=1&I=LXNA35&P=7
Autopilot (PA-2 Pilot AssistLink) sensor from Futaba.
This uses the horizon to maintain level flight.
The larger well stocked RC hobby shops also usually have these in stock too.
Accelerometers measure sudden movements from the current reference point.
Original Message
From: chris smith [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=oR0Q8i80wQJPOhEbapB1us4OmIwpq7bRdzUFIsCYa6Dxeb3ztZF1d9wIdtsn8ncHLsELn6uI6phX4zYNioYJGg]chris_smith_inc@y...[/url
Sent: Sunday, September 22, 2002 1:08 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] re: Accelerometer
would one of these devices from Parallex work
correctly as an artificial horizon for a model
aircraft?
I've been investigating solutions involving gyros and
accelerometers, but I thought accelerometers only gave
you rate of change, not the current angle (with
respect to ground plane) at time(t) for example.
Also, do they still work if they are upside down? For
example giving angles > 90 degrees?
thank you
chris
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autopilot/flight leveller i'm looking for. I have a
radio modem on the aircraft sending down telemetry to
a laptop. I'm writing software on the laptop to
display the telemetry. I wanted an artificial horizon
as one of my instruments.
I thought accelerometers only measured sudden
movements as you describe, but it sounds like some
people on the list are getting more of a gyroscopic
type reading (offset from ground/reference plane).
Can anyone confirm/refute this? thank you
chris
--- Earl Bollinger <earlwbollinger@a...> wrote:
> Actually you would want to use a
>
http://www2.towerhobbies.com/cgi-bin/wti0001p.pgm?Q=1&I=LXNA35&P=7
> Autopilot (PA-2 Pilot AssistLink) sensor from
> Futaba.
> This uses the horizon to maintain level flight.
> The larger well stocked RC hobby shops also usually
> have these in stock too.
> Accelerometers measure sudden movements from the
> current reference point.
>
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determine how far off from horizon level you are. You can send this signal
back down to the receiving station to feed a horizon indicator meter or
something. For example a 1.5ms pulse width is center(level), 1.6ms is tilt
right, 1.4 ms is tilt left.
The Futaba unit is actually feeding in a correction, so the signal tilt is
actually reversed from normal, as the unit is telling a aileron servo to
level the model plane.
Actually they use a simple potentiometer to measure from ground level.
One way is to have a little tail with the pot at one end and a stick just
touching the floor or ground, as the robot leans forward or back you can
measure the pot to determine how far off you are. But after you get the
formulas and math working you can forgo the pot then. Ultrasound and IR
sensors aren't sensitive enough to small changes.
The gyroscope only reacts to relatively fast changes, if the robot for
example is sitting still, a slow precesion or tilt can start to occur that
the gyro doesn't respond to, thus the accelerometer is used to catch this
slow creeping error that occurs. You could forgo the acceleromter if your
using a potentiometer to catch the error in drift as it occurs.
Original Message
From: chris smith [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Jyg30tslkZo3iaX36netrkRQrcGTEFlzgopE-otR7XEjg3N61Qf87hYrpKmtlTdXW-GYEMSt1jmUOtQUy2p7WvFSZ3k]chris_smith_inc@y...[/url
Sent: Sunday, September 22, 2002 2:24 PM
To: basicstamps@yahoogroups.com
Subject: RE: [noparse][[/noparse]basicstamps] re: Accelerometer
thanks for the tip Earl. Actually though it isn't an
autopilot/flight leveller i'm looking for. I have a
radio modem on the aircraft sending down telemetry to
a laptop. I'm writing software on the laptop to
display the telemetry. I wanted an artificial horizon
as one of my instruments.
I thought accelerometers only measured sudden
movements as you describe, but it sounds like some
people on the list are getting more of a gyroscopic
type reading (offset from ground/reference plane).
Can anyone confirm/refute this? thank you
chris
--- Earl Bollinger <earlwbollinger@a...> wrote:
> Actually you would want to use a
>
http://www2.towerhobbies.com/cgi-bin/wti0001p.pgm?Q=1&I=LXNA35&P=7
> Autopilot (PA-2 Pilot AssistLink) sensor from
> Futaba.
> This uses the horizon to maintain level flight.
> The larger well stocked RC hobby shops also usually
> have these in stock too.
> Accelerometers measure sudden movements from the
> current reference point.
>
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Apparently my earlier reply was missed or mis-read as Earl makes a
incorrect assumption about the ADXL202. It does indeed output a STEADY
pulse width signal in 2 axis WHILE the device is tilted, so yes in that case
it would work as a horizion.
I too was surprised to learn that it didn't JUST respond when a change
was made and then go back to "idle". This mode of operation is referred to
by AD as the "tilt sensor" mode. I am using it in my R/C submarine project
for exactly the purpose of determining the pitch angle of the boat ( to help
control depth while submerged) and will use the other axis (roll) to tell me
(the on board processor that is) if the sub has hit a wave and rolled over
there by letting all the air out of the ballast tanks. (Not good !)
Buy the eval board, you'll love it..
Mike B.
Original Message
From: "chris smith" <chris_smith_inc@y...>
To: <basicstamps@yahoogroups.com>
Sent: Sunday, September 22, 2002 11:07 AM
Subject: [noparse][[/noparse]basicstamps] re: Accelerometer
> would one of these devices from Parallex work
> correctly as an artificial horizon for a model
> aircraft?
>
> I've been investigating solutions involving gyros and
> accelerometers, but I thought accelerometers only gave
> you rate of change, not the current angle (with
> respect to ground plane) at time(t) for example.
> Also, do they still work if they are upside down? For
> example giving angles > 90 degrees?
>
> thank you
>
> chris
>
>
> __________________________________________________
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> New DSL Internet Access from SBC & Yahoo!
> http://sbc.yahoo.com
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> basicstamps-unsubscribe@yahoogroups.com
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Body of the message will be ignored.
>
>
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>
>
:-)
chris
--- Mike Blier <w6ffc@p...> wrote:
> Hi Chris:
>
> Apparently my earlier reply was missed or
> mis-read as Earl makes a
> incorrect assumption about the ADXL202. It does
> indeed output a STEADY
> pulse width signal in 2 axis WHILE the device is
> tilted, so yes in that case
> it would work as a horizion.
>
> I too was surprised to learn that it didn't JUST
> respond when a change
> was made and then go back to "idle". This mode of
> operation is referred to
> by AD as the "tilt sensor" mode. I am using it in
> my R/C submarine project
> for exactly the purpose of determining the pitch
> angle of the boat ( to help
> control depth while submerged) and will use the
> other axis (roll) to tell me
> (the on board processor that is) if the sub has hit
> a wave and rolled over
> there by letting all the air out of the ballast
> tanks. (Not good !)
>
> Buy the eval board, you'll love it..
>
> Mike B.
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