Garmin GPS III+ interface
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Posts: 46,084
Hi Everybody,
I'm looking to interface a Garmin GPS III plus with a B2SX. Since I ride the
short bus, sample code and connections would be a really big plus.
Hope y'all had a good summer!
Jonathan Peakall
I'm looking to interface a Garmin GPS III plus with a B2SX. Since I ride the
short bus, sample code and connections would be a really big plus.
Hope y'all had a good summer!
Jonathan Peakall
Comments
take a look at the Parallax web site for Jon Williams articles on
interfacing a GPS receiver with a BS2 in the model airplane. There is also
some articles published in Nuts & Volts that cover this. You just have to
make sure the Garmin has an output available for the Tx0 and Rx0 serial code
lines (raised to TTL levels) to interface the receiver with the Stamp before
you begin to play with the code. Real time GPS is a little difficult to
acquire at times as I think you are saying that you are riding a bus. I
have it in vehicles from a wrist worn device, acquisition is good, but not
perfect all the time. You will see as you experiment with getting "good
fixes". A good gain antenna ~26 dB is essential and it must be an active
type, LNA with 3.3 volts going to it from the receiver. Most of the sats
come in around 20 degrees off the horizon and the GPS antennas are omni
directional. Some do better than others in portable applications. A ground
plane such as a vehicle using a magnet mount is the best. Without some sort
of ground plane, it is a lot harder to acquire in a short time period
whether it be a cold boot ( no data stored) or a warm boot ( battery backup)
I am doing some work with our design right now before production and it
takes a lot of time to test.
have fun
mike m
Original Message
From: Jonathan Peakall <jpeakall@m...>
To: <basicstamps@yahoogroups.com>
Sent: Thursday, August 22, 2002 9:42 PM
Subject: [noparse][[/noparse]basicstamps] Garmin GPS III+ interface
> Hi Everybody,
>
> I'm looking to interface a Garmin GPS III plus with a B2SX. Since I ride
the
> short bus, sample code and connections would be a really big plus.
>
> Hope y'all had a good summer!
>
> Jonathan Peakall
>
>
> 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/
>
>
>
The reference to the short bus was a disparagement of my mental abilities,
not where I will be using the unit. I have seen the article you mention, but
it was using a b2p and an Etrex gps, not a III+. I didn't see any hook up
details. I just want to be sure of what I am doing before I hook it up to
the GPS, I don't want to buy a new one, I need it for other purposes!
So, is it as easy as one pin to the TX pin of the GPS and one to the RX,
connect to two stamp pins of my choice, and do a few serin/serouts? Will
the code in the article work for a b2sx?
Thanks,
Jonathan Peakall
> Dear Jonathan,
> take a look at the Parallax web site for Jon Williams articles on
> interfacing a GPS receiver with a BS2 in the model airplane. There is
also
> some articles published in Nuts & Volts that cover this. You just have to
> make sure the Garmin has an output available for the Tx0 and Rx0 serial
code
> lines (raised to TTL levels) to interface the receiver with the Stamp
before
> you begin to play with the code. Real time GPS is a little difficult to
> acquire at times as I think you are saying that you are riding a bus. I
> have it in vehicles from a wrist worn device, acquisition is good, but
not
> perfect all the time. You will see as you experiment with getting "good
> fixes". A good gain antenna ~26 dB is essential and it must be an active
> type, LNA with 3.3 volts going to it from the receiver. Most of the
sats
> come in around 20 degrees off the horizon and the GPS antennas are omni
> directional. Some do better than others in portable applications. A
ground
> plane such as a vehicle using a magnet mount is the best. Without some
sort
> of ground plane, it is a lot harder to acquire in a short time period
> whether it be a cold boot ( no data stored) or a warm boot ( battery
backup)
> I am doing some work with our design right now before production and it
> takes a lot of time to test.
> have fun
>
> mike m
we all go through that, trust me! I used the BS2 and the BS2p chips with
the code and I am not sure if the sx will do the same. best thing is to put
the question out to Jon or the group. I would think it would work, but the
code may have to be changed and I would say to use the chip it was written
for and not waste time doing code change. The only thing I can say is to
try and find out from Garmin (good luck) if the I/O connector on the unit
has the Tx0 and Rx0 lines on it. I have an older Street Pilot that has it
on the power connector pins. Look at your owner's manual and you might find
it on the power plug diagram. Make sure you run it through a MAX 2323 or
232 chip tom change the levels as you won't see a thing in the Stamp. Not
hard to do only 2 pins in and 2 out with a cap or two. If you need
schematic, e-mail me and I will show you. Keep on trying Worst case, buy a
little GPS OEM module which I use and it works fine. I can seer you to
some inexpensive ones as I did to others in the group before cya
mike m
Original Message
From: Jonathan Peakall <jpeakall@m...>
To: <basicstamps@yahoogroups.com>
Sent: Thursday, August 22, 2002 11:03 PM
Subject: Re: [noparse][[/noparse]basicstamps] Garmin GPS III+ interface
> Mike,
>
> The reference to the short bus was a disparagement of my mental abilities,
> not where I will be using the unit. I have seen the article you mention,
but
> it was using a b2p and an Etrex gps, not a III+. I didn't see any hook up
> details. I just want to be sure of what I am doing before I hook it up to
> the GPS, I don't want to buy a new one, I need it for other purposes!
>
> So, is it as easy as one pin to the TX pin of the GPS and one to the RX,
> connect to two stamp pins of my choice, and do a few serin/serouts? Will
> the code in the article work for a b2sx?
> Thanks,
>
> Jonathan Peakall
>
>
> > Dear Jonathan,
> > take a look at the Parallax web site for Jon Williams articles on
> > interfacing a GPS receiver with a BS2 in the model airplane. There is
> also
> > some articles published in Nuts & Volts that cover this. You just have
to
> > make sure the Garmin has an output available for the Tx0 and Rx0 serial
> code
> > lines (raised to TTL levels) to interface the receiver with the Stamp
> before
> > you begin to play with the code. Real time GPS is a little difficult to
> > acquire at times as I think you are saying that you are riding a bus. I
> > have it in vehicles from a wrist worn device, acquisition is good, but
> not
> > perfect all the time. You will see as you experiment with getting "good
> > fixes". A good gain antenna ~26 dB is essential and it must be an
active
> > type, LNA with 3.3 volts going to it from the receiver. Most of the
> sats
> > come in around 20 degrees off the horizon and the GPS antennas are omni
> > directional. Some do better than others in portable applications. A
> ground
> > plane such as a vehicle using a magnet mount is the best. Without some
> sort
> > of ground plane, it is a lot harder to acquire in a short time period
> > whether it be a cold boot ( no data stored) or a warm boot ( battery
> backup)
> > I am doing some work with our design right now before production and it
> > takes a lot of time to test.
> > have fun
> >
> > mike m
>
>
>
> 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/
>
>
Well, I'm commited to using the 2SX, I'm a poor rural science teacher, and I
have it ;-)
The GPS III + does have TxO and RxO pins. A circuit example would be
terrific. Is it possible to use 741 op amps or 386 audio amps to amplify the
signal. My access to parts is mail order, and it takes a while to get here.
Let's guess the Radio Shack in Fort Bragg CA (pop. 15k, 25 miles away,
nearest "big town") doesn't have the MAX2323 chip.
I also have a Motorola GT plus Oncore that I haven't played with at all yet,
don't have an antenna. Is it any easier to interface this one? For now, my
main desire is to access the atomic clock time for a seismograph I have
built. What OEM modules do you have access to, and how much?
I assume as long as I don't allow any stray voltage into the GPS pins, the
GPS should be relativly safe? It can handle the 5v input for the stamp,
right? Just don't want to blow the GPS.
Original Message
From: M. E. M. Electronics <memelectronics@e...>
To: <basicstamps@yahoogroups.com>
Sent: Friday, August 23, 2002 5:40 AM
Subject: Re: [noparse][[/noparse]basicstamps] Garmin GPS III+ interface
> Dear Jonathan,
> we all go through that, trust me! I used the BS2 and the BS2p chips with
> the code and I am not sure if the sx will do the same. best thing is to
put
> the question out to Jon or the group. I would think it would work, but
the
> code may have to be changed and I would say to use the chip it was written
> for and not waste time doing code change. The only thing I can say is to
> try and find out from Garmin (good luck) if the I/O connector on the unit
> has the Tx0 and Rx0 lines on it. I have an older Street Pilot that has it
> on the power connector pins. Look at your owner's manual and you might
find
> it on the power plug diagram. Make sure you run it through a MAX 2323
or
> 232 chip tom change the levels as you won't see a thing in the Stamp. Not
> hard to do only 2 pins in and 2 out with a cap or two. If you need
> schematic, e-mail me and I will show you. Keep on trying Worst case, buy
a
> little GPS OEM module which I use and it works fine. I can seer you to
> some inexpensive ones as I did to others in the group before cya
> mike m
>
Original Message
> From: Jonathan Peakall <jpeakall@m...>
> To: <basicstamps@yahoogroups.com>
> Sent: Thursday, August 22, 2002 11:03 PM
> Subject: Re: [noparse][[/noparse]basicstamps] Garmin GPS III+ interface
>
>
> > Mike,
> >
> > The reference to the short bus was a disparagement of my mental
abilities,
> > not where I will be using the unit. I have seen the article you mention,
> but
> > it was using a b2p and an Etrex gps, not a III+. I didn't see any hook
up
> > details. I just want to be sure of what I am doing before I hook it up
to
> > the GPS, I don't want to buy a new one, I need it for other purposes!
> >
> > So, is it as easy as one pin to the TX pin of the GPS and one to the RX,
> > connect to two stamp pins of my choice, and do a few serin/serouts?
Will
> > the code in the article work for a b2sx?
> > Thanks,
> >
> > Jonathan Peakall
> >
> >
> > > Dear Jonathan,
> > > take a look at the Parallax web site for Jon Williams articles on
> > > interfacing a GPS receiver with a BS2 in the model airplane. There is
> > also
> > > some articles published in Nuts & Volts that cover this. You just
have
> to
> > > make sure the Garmin has an output available for the Tx0 and Rx0
serial
> > code
> > > lines (raised to TTL levels) to interface the receiver with the Stamp
> > before
> > > you begin to play with the code. Real time GPS is a little difficult
to
> > > acquire at times as I think you are saying that you are riding a bus.
I
> > > have it in vehicles from a wrist worn device, acquisition is good,
but
> > not
> > > perfect all the time. You will see as you experiment with getting
"good
> > > fixes". A good gain antenna ~26 dB is essential and it must be an
> active
> > > type, LNA with 3.3 volts going to it from the receiver. Most of the
> > sats
> > > come in around 20 degrees off the horizon and the GPS antennas are
omni
> > > directional. Some do better than others in portable applications. A
> > ground
> > > plane such as a vehicle using a magnet mount is the best. Without
some
> > sort
> > > of ground plane, it is a lot harder to acquire in a short time period
> > > whether it be a cold boot ( no data stored) or a warm boot ( battery
> > backup)
> > > I am doing some work with our design right now before production and
it
> > > takes a lot of time to test.
> > > have fun
> > >
> > > mike m
> >
> >
> >
> > 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/
>
>
>
I have a Garmin 12XL and a BS2p. I can't verify the BS2sx but you
can experiment with the code. First of all I had to remember to
switch mine from native Garmin to NMEA 4800 baud then it began
working but I got Very Strange numbers. The code for the
Garmin E-Trax needed some modification for the 12XL. The NMEA
output is a comma separated format so I just added a small section
of code to print the NMEA sentance and stop. The I read off the
positions that I needed to take the data from and it worked fine.
Here is the block of code I added:
'This block will write out the NMEA Sentance with byte positions
debug "Here is the NMEA Sentance", cr, cr
FOR temp = 1 to 65
debug temp
Next
debug "123456789012345678901234567890123456789012345678901234567890123
45", cr
debug " 1 2 3 4 5
6", cr, cr
debug "this is your NMEA Sentance and the strings byte positions."
end
' End of NMEA Sentance Writing Section
Good Luck
Phillip
--- In basicstamps@y..., "M. E. M. Electronics" <memelectronics@e...>
wrote:
> Dear Jonathan,
> we all go through that, trust me! I used the BS2 and the BS2p
chips with
> the code and I am not sure if the sx will do the same. best thing
is to put
> the question out to Jon or the group. I would think it would work,
but the
> code may have to be changed and I would say to use the chip it was
written
> for and not waste time doing code change. The only thing I can say
is to
> try and find out from Garmin (good luck) if the I/O connector on
the unit
> has the Tx0 and Rx0 lines on it. I have an older Street Pilot that
has it
> on the power connector pins. Look at your owner's manual and you
might find
> it on the power plug diagram. Make sure you run it through a
MAX 2323 or
> 232 chip tom change the levels as you won't see a thing in the
Stamp. Not
> hard to do only 2 pins in and 2 out with a cap or two. If you need
> schematic, e-mail me and I will show you. Keep on trying Worst
case, buy a
> little GPS OEM module which I use and it works fine. I can seer
you to
> some inexpensive ones as I did to others in the group before cya
> mike m
>
Original Message
> From: Jonathan Peakall <jpeakall@m...>
> To: <basicstamps@y...>
> Sent: Thursday, August 22, 2002 11:03 PM
> Subject: Re: [noparse][[/noparse]basicstamps] Garmin GPS III+ interface
>
>
> > Mike,
> >
> > The reference to the short bus was a disparagement of my mental
abilities,
> > not where I will be using the unit. I have seen the article you
mention,
> but
> > it was using a b2p and an Etrex gps, not a III+. I didn't see any
hook up
> > details. I just want to be sure of what I am doing before I hook
it up to
> > the GPS, I don't want to buy a new one, I need it for other
purposes!
> >
> > So, is it as easy as one pin to the TX pin of the GPS and one to
the RX,
> > connect to two stamp pins of my choice, and do a few
serin/serouts? Will
> > the code in the article work for a b2sx?
> > Thanks,
> >
> > Jonathan Peakall
> >
> >
> > > Dear Jonathan,
> > > take a look at the Parallax web site for Jon Williams
articles on
> > > interfacing a GPS receiver with a BS2 in the model airplane.
There is
> > also
> > > some articles published in Nuts & Volts that cover this. You
just have
> to
> > > make sure the Garmin has an output available for the Tx0 and
Rx0 serial
> > code
> > > lines (raised to TTL levels) to interface the receiver with the
Stamp
> > before
> > > you begin to play with the code. Real time GPS is a little
difficult to
> > > acquire at times as I think you are saying that you are riding
a bus. I
> > > have it in vehicles from a wrist worn device, acquisition is
good, but
> > not
> > > perfect all the time. You will see as you experiment with
getting "good
> > > fixes". A good gain antenna ~26 dB is essential and it must be
an
> active
> > > type, LNA with 3.3 volts going to it from the receiver. Most
of the
> > sats
> > > come in around 20 degrees off the horizon and the GPS antennas
are omni
> > > directional. Some do better than others in portable
applications. A
> > ground
> > > plane such as a vehicle using a magnet mount is the best.
Without some
> > sort
> > > of ground plane, it is a lot harder to acquire in a short time
period
> > > whether it be a cold boot ( no data stored) or a warm boot (
battery
> > backup)
> > > I am doing some work with our design right now before
production and it
> > > takes a lot of time to test.
> > > have fun
> > >
> > > mike m
> >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@y...
> > 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/
> >
> >
The NMEA interface specification is available on the Web and
explains the different types of sentences that can be transmitted by a GPS.
I would recommend getting a program to read the serial output from your GPS,
such RS232M from www.viddata.com to see which sentences your GPS actually
transmits and the exact format it uses. Then using the sentence structure
that you know you system is transmitting, begin to experiment with the serin
command. As you will learn, most GPS transmit at 4800 baud, although yours
might have other capability.
While you could direct connect the transmit terminal and ground from
the GPS to your Stamp, I would recommend putting a resistor of about 10K
between the transmit terminal and the input pin on the Stamp. This avoids
problems with a direct short and helps deal with the different voltage
levels. Serial data from the GPS is +/- 12 volts and the stamp expects 0 -
5 volts.
The biggest problem you will likely encounter is that reading a
single and entire NMEA sentence on the BS2SX is very hard. The BS2P has the
ability to input directly to the scratch pad ram using serin, as done in the
sample code from the Parallax site. That command is not available on the
2SX. So, you have to settle for reading the NMEA sentence in sections or
pieces (i.e. read the first part of the sentence with one serin, store to
eeprom or something, and read the second part of the sentence in another
serin).
Recently, I have successfully interfaced a Garmin Etrex to the 2SX
to accomplish dead reckoning when the GPS signal is lost, and would be happy
to send you the code and schematic if you want.
Chris
Original Message
From: Jonathan Peakall [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=JjQwuSWF89dC1tpDJCQ1oOEU70td6To6EEEu9CYOaLtmdDZqHf3GlKHPziWxhiaNpFIMjVVrgxqgqnrA]jpeakall@m...[/url
Sent: Thursday, August 22, 2002 9:43 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Garmin GPS III+ interface
Hi Everybody,
I'm looking to interface a Garmin GPS III plus with a B2SX. Since I ride the
short bus, sample code and connections would be a really big plus.
Hope y'all had a good summer!
Jonathan Peakall
To UNSUBSCRIBE, just send mail to:
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[noparse][[/noparse]Non-text portions of this message have been removed]
with BSII to read gps info and control a Remote Control truck. I am currently
working on GPS guided model airplane using micromint picstic 34, the BSII will
be in there also for some other tasks. Info at www.stoneflyers.com Good
luck,Matt Klarich
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[noparse][[/noparse]Non-text portions of this message have been removed]