Beaver
Guest
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 Posted:
Thu Dec 23, 2004 10:38 pm Post subject:
Folowup : Looking for Notebook GPS with both USB and Serial |
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Thank U for all the responses, what a great group
What I would like to achieve is a mouse type gps WAAS enabled if possible
that would transmit an NMEA string to both my USB input notebook and serial
input ham radio and this simultaneously and have GPS on all the time without
having to turn on a power switch. I understand that power has to be fed to
the gps, it could be by 12V DC, PS2 or USB depending on notebook , ham radio
usage or both. Can I build such an wiring pigtail ? Any schematic ?
Thank U Davi for the Deluo.com info, they offer 2 type of adapters
http://www.deluoelectronics.com/customer/product.php?productid=12
But I would like to feed both at the same time when needed.
Thank you all again
Paul |
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Jack Erbes
Guest
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| Posted:
Fri Dec 24, 2004 6:47 pm Post subject:
Re: Folowup : Looking for Notebook GPS with both USB and Ser |
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Beaver wrote:
| Quote: | Thank U for all the responses, what a great group
What I would like to achieve is a mouse type gps WAAS enabled if possible
that would transmit an NMEA string to both my USB input notebook and serial
input ham radio and this simultaneously and have GPS on all the time without
having to turn on a power switch. I understand that power has to be fed to
the gps, it could be by 12V DC, PS2 or USB depending on notebook , ham radio
usage or both. Can I build such an wiring pigtail ? Any schematic ?
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Is this in an automobile or something that has a battery for starting?
If yes, it sounds like you want to power your GPS receiver off the
battery or always on side of your ignition system. I'd put a switch
(and a fuse of course) on the connection anyway just in case I wanted to
isolate it for long term non-use, trouble shooting, storage or something.
I assume your GPS receiver will have a DC-DC adapter to drop the voltage
for the receiver, that is a good thing to have in this install because
it will isolate the GPS receiver from any voltage variations from the
battery. It the GPS will handle a wide range input voltages, like 10 to
40 Volts, it has a DC-DC adapter built into it and should be fine wired
direct to the battery voltage (again fused and maybe switched).
Doing that means your GPS receiver can, in theory, drain your starting
battery but that happening would be a real long shot unless the battery
was not charged for several months or more.
Your notebook and ham radio are both NMEA listeners, not talkers, so
they can both listen to the one NMEA data stream from the GPS.
Run the NMEA data lines to a terminal strip and make two connections
there, one to the radio and the other to the laptop. The USB connection
will need a serial to USB adapter either at the point where the NMEA
connections are made or at the notebook.
There are a lot of options for the permanent or built into the car
connectors for the two NMEA outputs. A project box or small panel with
a pair of panel mount DB-9F connectors are one method. Then you could
run a DB9-M/DB9-F cable to the serial port and connect a serial to USB
adapter (normally DB9-M) to the other.
The wiring is simple enough. If you skip the terminal strip and simply
connect the NMEA leads to the two DB9F connectors it would be like this:
GPS NMEA+(aka TXD)---DB9F Pin 2 (RXD)--DB9F Pin 2 (RXD)
GPS NMEA-(aka RXD)---DB9F Pin 3 (TXD)--DB9F Pin 3 (TXD)
GPS Ground-----------DB9F Pin 5 (GND)--DB9F Pin 5 (GND)
Note that TXD and RXD are not matched up, TXD goes to RXD and vice
versa. The ground connection on the GPS will most likely be the
negative side of the power source.
The two DB9F connectors are the ones on the panel or project box and
anything connected there will simply extend the run to where it is
needed. In the case of the serial to USB adapter, it both adapts to USB
and extends the run.
Jack
--
Jack Erbes in Ellsworth, Maine, USA - jackerbes at adelphia dot net
(also receiving email at jacker at midmaine.com) |
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