Re: GPS Serial
- From: "Al Dente" <nobody@xxxxxxxx>
- Date: Thu, 21 Jul 2005 15:24:19 GMT
here's some info I put together a while ago regarding interfacing my serial
GPS receiver to a Jornada. I've since done the same with my Ipaq2215...
maybe it will help you...
m9876c at yahoo dot com
To interface a Jornada 547 to a GPS receiver, you need the following:
1. A suitable GPS receiver, capable of outputting a NMEA signal thru a
serial cable. Can be a receiver/antenna unit such as the one sold by
Rand-McNally, or a stand-alone handheld GPS unit.
2. A Jornada equipped with a serial port cable, having a 9-pin female
connector
3. A null modem and gender changer to connect the 9-pin female serial
connector from the GPS receiver to the 9-pin female serial connector from
the Jornada
4. suitable software for the Jornada, such as Streets&Trips2002 with the GPS
patch applied
5. A source of power (typically 5 or 6 volts) for the GPS receiver if it
doesn't provide it's own power.
NULL-MODEM
When devices communicate over a serial connection, each device typically
provides 3 signals: Data being received, Data being transmitted, and ground.
For two devices to exchange information, you need to connect the Receive
wire from one to the Transmit wire of the other, do the same for the
remaining receive and transmit wires, and connect the two ground wires
together. This is what the null-modem does. Since both cables are female,
you will also need to add a gender changer so that you end up with two male
9-pin serial connectors, with a null-modem between them. The null-modem and
gender changer can be purchased for less than $10 each in computer supply
stores, or you could simply buy two male 9-pin connectors and wire them
together. Basically, you want to connect pin3 of one to pin2 of the other,
then connect the other pin2 to pin3, and finally connect pin5 to pin5. How
do you know which pin is which? The connectors I've seen have tiny numbers
next to each pin when you look down into the connector. If you can't find
numbers, just look into the connector and the pins are numbered like this:
1 2 3 4 5
6 7 8 9
POWER
The Rand-McNally GPS receiver comes with a male PS-2 connector at the end of
the cable, to be plugged into the MOUSE port of a laptop computer in order
to get the 5volts to power the receiver. There is also a female 9pin
connector that plugs into the serial port on the laptop to transfer data. I
understand the DeLorme GPS receivers have built-in batteries to provide
power. To use the Rand-McNally GPS with a Jornada, you need to provide the
5volts from a battery pack, connected to the PS-2 connector. The easiest way
to do this is to buy a 4-cell battery clip to hold 4 AA cells (or 4-C or 4-D
cells, if you don't mind carrying around the extra weight!), which will
provide approximately 6volts. The wires from the battery clip are then
connected to a female PS-2 connector, into which the male connector can be
plugged to turn on the GPS receiver. Which hole is which? If you look into
the female PS-2 connector, holding it with the little rectangular hole(the
"0" in the diagram below) toward the top, the holes are arranged like this:
6 5
0
(+) 4 3 (-)
1 2
Hole4 is +5volts, and hole3 is the negative wire from the batteries. I was
unable to find a female PS-2 connector, so I used a regular 5-pin DIN socket
I had on hand, then used a keyboard adaptor to convert that to the PS-2
connector I needed. It turned out to be a quick, cheap, and easy-to-wire
solution to the problem. If you do the same, the connections for the 5-pin
DIN socket are as follows:
3 1
(+) 5 4 (-)
2
Be sure to note that the above diagrams are looking into the SOCKET from
what will be the plug side, and that the (+) and (-) symbols are for the
positive and negative wires from the 6volt battery pack.
SOFTWARE
You need three pieces of software to interface to the Jornada:
1. Streets&Trips2002, about $30, although SAMs and COSTCO sell it for $13
after a rebate.
2. a 1.6meg patch that enables the GPS, available at:
http://www.microsoft.com/pocketstreets/
3. ACTIVESYNC3.5 to install the software from your computer to the Jornada
thru the serial cable
Install Activesync on your computer, so it will be available later. Then
install Streets&Trips2002. Finally, run the patch, which will modify the S&T
program. When you connect the Jornada, it will ask if you want to install
the program. Answer yes, and you will soon have a GPS-enabled version of S&T
on the Jornada. You can then use S&T on the main computer to create some
small maps for the Jornada, covering the areas you expect to need. These
maps can be kept on a removable memory card, but I suggest that you copy any
map you want to use into the Jornada's memory, so it will be accessed
faster. Trust me, it does make a difference, especially with maps that are
several meg in size!
USING IT
Connect the GPS to the Jornada using the null-modem, connect the GPS to the
power source, start the Jornada, and then start the S&T program on it. You
will need to select a map (should be in main memory!), then go down to
TOOLS, select GPS, and start it up. Depending on how clear your view of the
sky is, it may take a few minutes to acquire the satellites, but eventually
it will draw the map with a circle in the center, representing your
position. You can zoom in or out, depending on how much detail you want to
see. When you are finished using the GPS, be sure to unplug the power cord.
The receiver draws about 115ma from the battery, which should last several
hours.
.
- References:
- GPS Serial
- From: Damian Burrin
- GPS Serial
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