Compass Modules
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Posts: 46,084
Hi Folks,
I am trying to track the position of rotating disk over a 45 degree
range. Using a pot is too mechanical and prone to failiur. So I am
thinking of using a digital compass.
I found the "Precision Navigation Inc" compass module which sounds
perfect with a 1deg resolution but it outputs its data in a 3 wire
serial format(according to the Jameco Catalog it is compatible
with Motorola SPI and National Microware).
Here are my questions:
Can I read the 3 wire serial using a BS2?
Can I modify that signal into a standard RS232? how?
Is there a different module that can give me the precision but already
in an RS232 format that I can plug directly into the BS2?
Many Thanks
Al Najjar
I am trying to track the position of rotating disk over a 45 degree
range. Using a pot is too mechanical and prone to failiur. So I am
thinking of using a digital compass.
I found the "Precision Navigation Inc" compass module which sounds
perfect with a 1deg resolution but it outputs its data in a 3 wire
serial format(according to the Jameco Catalog it is compatible
with Motorola SPI and National Microware).
Here are my questions:
Can I read the 3 wire serial using a BS2?
Can I modify that signal into a standard RS232? how?
Is there a different module that can give me the precision but already
in an RS232 format that I can plug directly into the BS2?
Many Thanks
Al Najjar
Comments
This may work, it's not RS232 but it is easy to interface to a BS2.
http://www.robot-electronics.co.uk/htm/cmps.shtml
Later
Dan
--- In basicstamps@y..., brownstamp@y... wrote:
> Hi Folks,
>
> I am trying to track the position of rotating disk over a 45 degree
> range. Using a pot is too mechanical and prone to failiur. So I
am
> thinking of using a digital compass.
>
> I found the "Precision Navigation Inc" compass module which sounds
> perfect with a 1deg resolution but it outputs its data in a 3 wire
> serial format(according to the Jameco Catalog it is compatible
> with Motorola SPI and National Microware).
>
> Here are my questions:
>
> Can I read the 3 wire serial using a BS2?
> Can I modify that signal into a standard RS232? how?
> Is there a different module that can give me the precision but
already
> in an RS232 format that I can plug directly into the BS2?
>
>
> Many Thanks
>
> Al Najjar
use an optical encoder, or a Hall effect sensor. Will be more cheap and
reliable. How many bits (accuracy) do you need ?
ACJacques
very ease
>
> Hi Folks,
>
> I am trying to track the position of rotating disk over a 45 degree
> range. Using a pot is too mechanical and prone to failiur. So I am
> thinking of using a digital compass.
>
> I found the "Precision Navigation Inc" compass module which sounds
> perfect with a 1deg resolution but it outputs its data in a 3 wire
> serial format(according to the Jameco Catalog it is compatible
> with Motorola SPI and National Microware).
>
> Here are my questions:
>
> Can I read the 3 wire serial using a BS2?
> Can I modify that signal into a standard RS232? how?
> Is there a different module that can give me the precision but already
> in an RS232 format that I can plug directly into the BS2?
>
> Many Thanks
>
> Al Najjar
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
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of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
not have the problems pointed, but they are a bit expensive. Since range
is only 45 degree it seems to me easy to implement a proximity sensing.
The only drawback is translation from rotary movement into a linear. May
be a lookup table or a simple rack pinion gear mechanical device solve
this. This approach may be more accurate that a V2X compass, that output
may vary with several factors like temperature, magnetic fields in
nearby and also does not have the required lineary because the inherent
2 axis field distortion. The V2X may output 30 degree or less for a real
45 movement in certain angle sector,and in another moment change to 50.
ACJacques
brownstamp@y... wrote:
>
> Thanks for the suggestion. I need a 1 degree resolution. I used a
> high quality Pot that but that gets abused badly as this is an exhibit
> in a very busy museum. The pot brush or wiper wears out somehow!
>
> Optical encoders is something that I considered, the problem here is
> that I need to give it some initial position feedback as a starting
> point everytime the unit is powered down. SInce I have little space,
> I am trying to avoid additional contact switches etc. Is the BS2
> fast enough to count the rotation from an encoder via the "pulsin"
> command?
>
> I thought that Hall Effect sensors give you proximity linear
> measurement and I am not sure how I can use it to give me angular
> position! Could you clarify your suggestions?
>
> Al
brownstamp@y... wrote:
>
> Hi Folks,
>
> I am trying to track the position of rotating disk over a 45 degree
> range. Using a pot is too mechanical and prone to failiur. So I am
> thinking of using a digital compass.
>
> I found the "Precision Navigation Inc" compass module which sounds
> perfect with a 1deg resolution but it outputs its data in a 3 wire
> serial format(according to the Jameco Catalog it is compatible
> with Motorola SPI and National Microware).
>
> Here are my questions:
>
> Can I read the 3 wire serial using a BS2?
> Can I modify that signal into a standard RS232? how?
> Is there a different module that can give me the precision but already
> in an RS232 format that I can plug directly into the BS2?
>
> Many Thanks
>
> Al Najjar
>
> 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/
> Hi Folks,
>
> I am trying to track the position of rotating disk over a 45 degree
> range. Using a pot is too mechanical and prone to failiur. So I
am
> thinking of using a digital compass.
>
> I found the "Precision Navigation Inc" compass module which sounds
> perfect with a 1deg resolution but it outputs its data in a 3 wire
> serial format(according to the Jameco Catalog it is compatible
> with Motorola SPI and National Microware).
>
> Here are my questions:
>
> Can I read the 3 wire serial using a BS2?
> Can I modify that signal into a standard RS232? how?
> Is there a different module that can give me the precision but
already
> in an RS232 format that I can plug directly into the BS2?
>
>
> Many Thanks
>
> Al Najjar
Al:
If you need 1 degree resolution, a Vector Compass module is not what
you want. Go to www.schaevitz.com for precision rotational sensors.
Regards,
J. Ross
ps: Vector takes at least 4 wires, preferably 6 to interface.
fairly good resoultion )couple of degrees possible??) as I was to be able to
feed the Stamp a realitive bearing of a directional antenna realitive to the
front of the vechile and come up with the actual magnetic bearing of the
antenna..
Thanks..
Mike B.
[noparse][[/noparse]Non-text portions of this message have been removed]
sensors at http://www.dinsmoresensors.com
Of which Parallax just happens to already have setup as a Appmod module.
http://www.parallax.com/detail.asp?product_id=29113
Another "digital"compass is the Deventech unit
http://www.acroname.com/robotics/parts/R117-COMPASS.html or at
http://www.junun.org/MarkIII/Info.jsp?item=26
Another nice one from Motorola is this one
http://www.ssec.honeywell.com/magnetic/landnav.html
But it appears to be expensive.
Another possibility is a handheld digital compass that has a serial
interface. Sort of like this one
http://sciencekit.com/category.asp?c=477284 (which doesn't have a serial
interface).
There are also a couple of different Hall effect sensor based compass
kits such as at http://www.alltronics.com/kits.htm.
These use a needle magnet with a circle of hall effect sensors arranged
around the circumference. As the needle moves past a hall effect sensor,
that sensor detects the needle and you can get the bearing.
Your sensitivity would be based on how many hall effect sensors you
arrange around the circumference of the magnetic needle.
Try a Google search on things like "digital compass", "digital compass
kit", and "hall effect compass kit".
Original Message
From: Mike Blier [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=H8q4I-ke1OhfOh3ha97j2izX5cg-c4rhhBvupwRX3N1Ih_H9U-4osDkVX4xaJBRy8qgZsjNZLjxp8FYhVCU]w4fej@b...[/url
Sent: Saturday, April 10, 2004 10:32 PM
To: Basicstamps@Yahoogroups.Com
Subject: [noparse][[/noparse]basicstamps] Compass modules
Anyone have and reccomendations for a compass chip to use with a Stamp?
Need fairly good resoultion )couple of degrees possible??) as I was to
be able to feed the Stamp a realitive bearing of a directional antenna
realitive to the front of the vechile and come up with the actual
magnetic bearing of the antenna..
Thanks..
Mike B.
[noparse][[/noparse]Non-text portions of this message have been removed]
To UNSUBSCRIBE, just send mail to:
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sensitive to nearby metal or stray magnetic fields. This tends to throw
them off, sometimes as much as 180 degrees too.
The metal in a vehicle may interfere too much with the compasses.
What you may have to do is use a GPS unit with a serial interface and
use it to get the heading or bearing. The GPS unit would effectively
move the compass itself way out into space away from your vehicle or
nearby stray magnetic fields that would interfere with a good reading.
There are places in the United States (and other countries) where the
compass can read almost 180 degrees off, due to the iron ore deposits in
the ground. The Deventech or Dinsmore compasses I mentioned earlier are
so sensitive that they can pick up a small magnetized screwdriver tip
from several inches away or farther. Thus a metal building or electric
motors or nuts and bolts could cause it to be off a considerable amount.
Original Message
From: Mike Blier [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=4AHst_RrJ9wJJt8icddKU5GOZVhIgm6M7aKyJVoGXEuiOGnM7u0xChT-bz-EkHetIvmbVjGAtsx1mjo]w4fej@b...[/url
Sent: Saturday, April 10, 2004 10:32 PM
To: Basicstamps@Yahoogroups.Com
Subject: [noparse][[/noparse]basicstamps] Compass modules
Anyone have and reccomendations for a compass chip to use with a Stamp?
Need fairly good resoultion )couple of degrees possible??) as I was to
be able to feed the Stamp a realitive bearing of a directional antenna
realitive to the front of the vechile and come up with the actual
magnetic bearing of the antenna..
Thanks..
Mike B.
[noparse][[/noparse]Non-text portions of this message have been removed]
To UNSUBSCRIBE, just send mail to:
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that isn't a problem, regardless of which BASIC Stamp module you use.
If you're using something other than a BS2p or BS2pe, you'll need to
bit-bang the I2C routines.
-- Jon Williams
-- Applications Engineer, Parallax
-- Dallas Office
Original Message
From: Mike Blier [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Ee_e8GSObyV3zfU7oLzv1ZMoT8Ay2ax070sogSxkQjJdJUzfEsQD6gFvaEqoez2MI0RHKo1z3r_NlDo]w4fej@b...[/url
Sent: Saturday, April 10, 2004 10:32 PM
To: Basicstamps@Yahoogroups.Com
Subject: [noparse][[/noparse]basicstamps] Compass modules
Anyone have and reccomendations for a compass chip to use with a Stamp?
Need fairly good resoultion )couple of degrees possible??) as I was to
be able to feed the Stamp a realitive bearing of a directional antenna
realitive to the front of the vechile and come up with the actual
magnetic bearing of the antenna..
Thanks..
Mike B.
[noparse][[/noparse]Non-text portions of this message have been removed]
To UNSUBSCRIBE, just send mail to:
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from the same email address that you subscribed. Text in the Subject
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This message has been scanned by WebShield. Please report SPAM to
abuse@p....
it is several inches higher than my BOE-Bot.
-- Jon Williams
-- Applications Engineer, Parallax
-- Dallas Office
Original Message
From: Earl Bollinger [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Xr69AtYDfKuvFyWHAQGGk5NRTX8ZU1oCodIqnHgM95pDGTLFfKKX_ZEOWge44hv5o1SYSKnBKsC_0JIt-ULW6I7A_Vc]earlwbollinger@c...[/url
Sent: Sunday, April 11, 2004 8:17 AM
To: basicstamps@yahoogroups.com
Subject: RE: [noparse][[/noparse]basicstamps] Compass modules
I forgot to mention earlier that the compass modules are extremely
sensitive to nearby metal or stray magnetic fields. This tends to throw
them off, sometimes as much as 180 degrees too. The metal in a vehicle
may interfere too much with the compasses. What you may have to do is
use a GPS unit with a serial interface and use it to get the heading or
bearing. The GPS unit would effectively move the compass itself way out
into space away from your vehicle or nearby stray magnetic fields that
would interfere with a good reading.
There are places in the United States (and other countries) where the
compass can read almost 180 degrees off, due to the iron ore deposits in
the ground. The Deventech or Dinsmore compasses I mentioned earlier are
so sensitive that they can pick up a small magnetized screwdriver tip
from several inches away or farther. Thus a metal building or electric
motors or nuts and bolts could cause it to be off a considerable amount.
Original Message
From: Mike Blier [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=wrC4geerCPByrnhqFhLKDWz7ewV73hLSsE_gQZtioxhg9d9K8a9neq-LRaIPp_Nl5nJFpf6mUjq2RY4-Rw]w4fej@b...[/url
Sent: Saturday, April 10, 2004 10:32 PM
To: Basicstamps@Yahoogroups.Com
Subject: [noparse][[/noparse]basicstamps] Compass modules
Anyone have and reccomendations for a compass chip to use with a Stamp?
Need fairly good resoultion )couple of degrees possible??) as I was to
be able to feed the Stamp a realitive bearing of a directional antenna
realitive to the front of the vechile and come up with the actual
magnetic bearing of the antenna..
Thanks..
Mike B.
[noparse][[/noparse]Non-text portions of this message have been removed]
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Keep in mind that in places away from the equator the Earth's field is stronger
pointing down than it is in the horizontal plane. So if whatever sensor you're
using is not level an error will be introduced.
Dinsmore has a cleaver sensor that uses a magnet on a pivot that rotates like a
compass needle and a couple of Hall sensors at 90 degrees to each other.
Normal Hall sensors are not sensitive enough to detect the Earth's magnetic
field. You can read the output voltage of the two sensors as Sine and Cosine
and compute the direction. For more on sensors see my web page:
http://www.pacificsites.com/~brooke/Sensors.shtml
Have Fun,
Brooke Clarke, N6GCE
http://www.PRC68.com
From: Mike Blier [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=bJYomOKCc0lnhDtr5WD8ErtUGJvjkd65Fk5q5pHIZKQWtAT3heaPP4wblJd3Bt34eFkCzzgNw1j1]w4fej@b...[/url
Sent: Saturday, April 10, 2004 10:32 PM
To: Basicstamps@Yahoogroups.Com
Subject: [noparse][[/noparse]basicstamps] Compass modules
Anyone have and reccomendations for a compass chip to use with a Stamp?
Need fairly good resoultion )couple of degrees possible??) as I was to
be able to feed the Stamp a realitive bearing of a directional antenna
realitive to the front of the vechile and come up with the actual
magnetic bearing of the antenna..
Thanks..
Mike B.
to the Stamp before so no problem getting the data. I haven't noticed what
happens to the heading info (in the GPS) once the car has stopped for a
period of time. Most of the direction finding will take place in a stopped
condition. Does the heading "stick" to the last heading when the car was in
motion?? If it does then the GPS is probably the way to go. If it tends to
drift due to EPE (position error) then that could be a problem. I'll be
turning the antenna using a stepper so the realitive bearing to the front of
the car will infer it's bearing plus the car heading to come up with the
"true" bearing of the signal.. Am I missing anything here that might bite
me in the back side later??
Mike B.
Original Message
From: "Earl Bollinger" <earlwbollinger@c...>
To: <basicstamps@yahoogroups.com>
Sent: Sunday, April 11, 2004 9:16 AM
Subject: RE: [noparse][[/noparse]basicstamps] Compass modules
> I forgot to mention earlier that the compass modules are extremely
> sensitive to nearby metal or stray magnetic fields. This tends to throw
> them off, sometimes as much as 180 degrees too.
> The metal in a vehicle may interfere too much with the compasses.
> What you may have to do is use a GPS unit with a serial interface and
> use it to get the heading or bearing. The GPS unit would effectively
> move the compass itself way out into space away from your vehicle or
> nearby stray magnetic fields that would interfere with a good reading.
>
> There are places in the United States (and other countries) where the
> compass can read almost 180 degrees off, due to the iron ore deposits in
> the ground. The Deventech or Dinsmore compasses I mentioned earlier are
> so sensitive that they can pick up a small magnetized screwdriver tip
> from several inches away or farther. Thus a metal building or electric
> motors or nuts and bolts could cause it to be off a considerable amount.
>
>
Original Message
> From: Mike Blier [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=gqZNP0VwvLEuQeOHn_EJH2GeFjtB9Kj4v47GbMcnoZugqBM5CdWpZZVXTZyq7WSRDvrOc8oqOXKj19jm]w4fej@b...[/url
> Sent: Saturday, April 10, 2004 10:32 PM
> To: Basicstamps@Yahoogroups.Com
> Subject: [noparse][[/noparse]basicstamps] Compass modules
>
> Anyone have and reccomendations for a compass chip to use with a Stamp?
> Need fairly good resoultion )couple of degrees possible??) as I was to
> be able to feed the Stamp a realitive bearing of a directional antenna
> realitive to the front of the vechile and come up with the actual
> magnetic bearing of the antenna..
>
> Thanks..
>
> Mike B.
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
>
>
> 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:
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>
work a bit differently. The GPS compass will get 'stuck' at the last
heading the car was moving. However if you have a hand held GPS and
stay stationary then rotate and come back to your original heading,
the GPS compass may get confused and show a heading 180 degree's off.
Taking a few steps in any direction will correct the reading.
One other thing to keep in mind. Most lower priced portable GPS units
don't actually have a compass built into them. They use satellite GPS
information + movement to infer a compass heading. But some GPS units
also include an electronic compass that works independently of the GPS.
The Garmin eTrex Summit is a midpriced ($229) portable GPS with a
built-in compass and altimeter.
moving (heading is calculated from movement speed in two vectors [noparse][[/noparse]N/S
and E/W]). There are GPS units -- like the Garmin Summit -- that have a
built-in compass that will work when not moving.
-- Jon Williams
-- Applications Engineer, Parallax
-- Dallas Office
Original Message
From: Mike Blier [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=zAmORlKOQfRkcGecfCo957gHoyDbUO1t5H6a-vNg5QCkkd22qNsx3x_hq-aGuahi_X84nDZvS8t0Mg]w4fej@b...[/url
Sent: Sunday, April 11, 2004 10:18 AM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Compass modules
Thanks for the replys. I do have GPS available in the car and have
"talked" to the Stamp before so no problem getting the data. I haven't
noticed what happens to the heading info (in the GPS) once the car has
stopped for a period of time. Most of the direction finding will take
place in a stopped condition. Does the heading "stick" to the last
heading when the car was in motion?? If it does then the GPS is
probably the way to go. If it tends to drift due to EPE (position error)
then that could be a problem. I'll be turning the antenna using a
stepper so the realitive bearing to the front of the car will infer it's
bearing plus the car heading to come up with the "true" bearing of the
signal.. Am I missing anything here that might bite me in the back side
later??
Mike B.
Original Message
From: "Earl Bollinger" <earlwbollinger@c...>
To: <basicstamps@yahoogroups.com>
Sent: Sunday, April 11, 2004 9:16 AM
Subject: RE: [noparse][[/noparse]basicstamps] Compass modules
> I forgot to mention earlier that the compass modules are extremely
> sensitive to nearby metal or stray magnetic fields. This tends to
> throw them off, sometimes as much as 180 degrees too. The metal in a
> vehicle may interfere too much with the compasses. What you may have
> to do is use a GPS unit with a serial interface and use it to get the
> heading or bearing. The GPS unit would effectively move the compass
> itself way out into space away from your vehicle or nearby stray
> magnetic fields that would interfere with a good reading.
>
> There are places in the United States (and other countries) where the
> compass can read almost 180 degrees off, due to the iron ore deposits
> in the ground. The Deventech or Dinsmore compasses I mentioned earlier
> are so sensitive that they can pick up a small magnetized screwdriver
> tip from several inches away or farther. Thus a metal building or
> electric motors or nuts and bolts could cause it to be off a
> considerable amount.
>
>
Original Message
> From: Mike Blier [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=zAmORlKOQfRkcGecfCo957gHoyDbUO1t5H6a-vNg5QCkkd22qNsx3x_hq-aGuahi_X84nDZvS8t0Mg]w4fej@b...[/url
> Sent: Saturday, April 10, 2004 10:32 PM
> To: Basicstamps@Yahoogroups.Com
> Subject: [noparse][[/noparse]basicstamps] Compass modules
>
> Anyone have and reccomendations for a compass chip to use with a
> Stamp? Need fairly good resoultion )couple of degrees possible??) as I
> was to be able to feed the Stamp a realitive bearing of a directional
> antenna realitive to the front of the vechile and come up with the
> actual magnetic bearing of the antenna..
>
> Thanks..
>
> Mike B.
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
>
>
> To UNSUBSCRIBE, just send mail to:
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> and Body of the message will be ignored.
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>
>
>
>
>
>
>
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you stop the vehicle.
But, sounds it like you need to try a test and see what it does for
real.
Original Message
From: Mike Blier [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=z_PW6qym-yVmw_EqLHtJUJHPLqv5tRf8pzkgl9ZqVuLUgqqGdZdZECYF8lruTFsHFi5FjoIagIWC]w4fej@b...[/url
Sent: Sunday, April 11, 2004 10:18 AM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Compass modules
Thanks for the replys. I do have GPS available in the car and have
"talked"
to the Stamp before so no problem getting the data. I haven't noticed
what
happens to the heading info (in the GPS) once the car has stopped for a
period of time. Most of the direction finding will take place in a
stopped
condition. Does the heading "stick" to the last heading when the car
was in
motion?? If it does then the GPS is probably the way to go. If it tends
to
drift due to EPE (position error) then that could be a problem. I'll be
turning the antenna using a stepper so the realitive bearing to the
front of
the car will infer it's bearing plus the car heading to come up with the
"true" bearing of the signal.. Am I missing anything here that might
bite
me in the back side later??
Mike B.
Original Message
From: "Earl Bollinger" <earlwbollinger@c...>
To: <basicstamps@yahoogroups.com>
Sent: Sunday, April 11, 2004 9:16 AM
Subject: RE: [noparse][[/noparse]basicstamps] Compass modules
> I forgot to mention earlier that the compass modules are extremely
> sensitive to nearby metal or stray magnetic fields. This tends to
throw
> them off, sometimes as much as 180 degrees too.
> The metal in a vehicle may interfere too much with the compasses.
> What you may have to do is use a GPS unit with a serial interface and
> use it to get the heading or bearing. The GPS unit would effectively
> move the compass itself way out into space away from your vehicle or
> nearby stray magnetic fields that would interfere with a good reading.
>
> There are places in the United States (and other countries) where the
> compass can read almost 180 degrees off, due to the iron ore deposits
in
> the ground. The Deventech or Dinsmore compasses I mentioned earlier
are
> so sensitive that they can pick up a small magnetized screwdriver tip
> from several inches away or farther. Thus a metal building or electric
> motors or nuts and bolts could cause it to be off a considerable
amount.
>
>
Original Message
> From: Mike Blier [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=z_PW6qym-yVmw_EqLHtJUJHPLqv5tRf8pzkgl9ZqVuLUgqqGdZdZECYF8lruTFsHFi5FjoIagIWC]w4fej@b...[/url
> Sent: Saturday, April 10, 2004 10:32 PM
> To: Basicstamps@Yahoogroups.Com
> Subject: [noparse][[/noparse]basicstamps] Compass modules
>
> Anyone have and reccomendations for a compass chip to use with a
Stamp?
> Need fairly good resoultion )couple of degrees possible??) as I was to
> be able to feed the Stamp a realitive bearing of a directional antenna
> realitive to the front of the vechile and come up with the actual
> magnetic bearing of the antenna..
>
> Thanks..
>
> Mike B.
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
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compass readout but I believe it derives it's information from movement as
Jon stated. Might be a "sticky wicket" for my application unless I do
something like save the last heading when the speed hits zero or the like..
Interesting problem... Thanks for the input..
Mike B.
Original Message
From: "fab4442003" <fab4442003@y...>
To: <basicstamps@yahoogroups.com>
Sent: Sunday, April 11, 2004 1:21 PM
Subject: [noparse][[/noparse]basicstamps] Re: Compass modules
> I'm only familiar with hand held GPS units - so a built-in car GPS may
> work a bit differently. The GPS compass will get 'stuck' at the last
> heading the car was moving. However if you have a hand held GPS and
> stay stationary then rotate and come back to your original heading,
> the GPS compass may get confused and show a heading 180 degree's off.
> Taking a few steps in any direction will correct the reading.
>
> One other thing to keep in mind. Most lower priced portable GPS units
> don't actually have a compass built into them. They use satellite GPS
> information + movement to infer a compass heading. But some GPS units
> also include an electronic compass that works independently of the GPS.
> The Garmin eTrex Summit is a midpriced ($229) portable GPS with a
> built-in compass and altimeter.
>
>
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