Another solution for your bag of tricks

theprez98 · 09-04-2005

Here's one for your bag of tricks.

My setup is as follows: Dell Inspiron 4100 running Auditor Security Collection (Kismet + GPSdrive), Proxim 8470-WD (Atheros chipset), Magellan Meridian Platinum GPS.

I use a serial cable that runs from the back of the GPS to the serial port and also includes a lighter adapter to power the GPS. All of sudden, Kismet was reporting Lat/Longs of all zeroes and GPSdrive was reporting connection timed out to GPS. I confirmed the GPS was actually working and transmitting NMEA, no problem there. A cursory inspection of both the serial end of the cable and the GPS end of the cable found nothing amiss. I also inspected the serial port on the back of the laptop for bent/missing pins, still nothing.

I pulled out the multimeter to run some tests on the cable to determine if that could shed any light on the problem. About that time, I found several small pieces lying on the floor: a screw top, metal tip, fuse, and spring. The screw top of the lighter adapter had come apart, and the tip, fuse, and spring had actually fallen out of the lighter adapter!

I immediately replaced the spring, fuse and tip and screwed the top back on. My first inclination was that there wasn't any way that this could have been the source of the problem. But, I figured I might as well test it (and Dutch's prodding certainly helped). So, I re-connected the cable and of course, it worked immediately.

Perhaps someone else can shed some light on the details of why the lighter adapter had anything to do with the laptop not receiving the GPS data. The only information I can find is that it might have something to do with the ground.

Either way, it's another solution to add to your bag of tricks.

streaker69 · 09-04-2005

Could be an odd power save mode. Turn off serial port when running on battery.

King_Ice_Flash · 09-05-2005

Quote:

Originally Posted by streaker69

Could be an odd power save mode. Turn off serial port when running on battery.

Could the GPS require power to use the serial port (Does it work on another laptop w/o power)? Is it possible that the cable needs power to work? Could it be the laptop be shutting the serial port down when it doesn't have ext power? The inside of the power plug didn't short out when it fell apart, did it?

theprez98 · 09-05-2005

Quote:

Originally Posted by King_Ice_Flash

Could the GPS require power to use the serial port (Does it work on another laptop w/o power)? Is it possible that the cable needs power to work? Could it be the laptop be shutting the serial port down when it doesn't have ext power? The inside of the power plug didn't short out when it fell apart, did it?

The GPS has batteries which it uses for power when the lighter adapter is not being used. I usually run the laptop off an inverter but I run off the laptop batteries sometimes for short trips, neither has given me any problems with the serial port. So the laptop shutting down the serial port without external power is not an issue, either.

I have no idea what happened, other than that when I reassembled the lighter adapter, everything worked again.

Thorn · 09-05-2005

Quote:

Originally Posted by theprez98

The GPS has batteries which it uses for power when the lighter adapter is not being used. I usually run the laptop off an inverter but I run off the laptop batteries sometimes for short trips, neither has given me any problems with the serial port. So the laptop shutting down the serial port without external power is not an issue, either.

I have no idea what happened, other than that when I reassembled the lighter adapter, everything worked again.

Many jacks where the external power adapter plugs in contain a switch that turns off and isolates the internal batteries. If the power adapter was plugged in, and it had lost the power, that might explain the behavior. Effectively the GPS would be dead for that time, and kismet would be reading zeros.

Airstreamer · 09-05-2005

Quote:

Originally Posted by Thorn

Many jacks where the external power adapter plugs in contain a switch that turns off and isolates the internal batteries. If the power adapter was plugged in, and it had lost the power, that might explain the behavior. Effectively the GPS would be dead for that time, and kismet would be reading zeros.

My Garmin Etrex Ledgend times out after 30 seconds if the external power dies. You have to hit a button to keep it alive off of the internal batteries. However, when it shuts down, it stays off. Even if external power is re-applied, so that probably isn't it. (More of an FYI.)

Starpoint · 09-05-2005

Quote:

Originally Posted by Airstreamer

My Garmin Etrex Ledgend times out after 30 seconds if the external power dies. You have to hit a button to keep it alive off of the internal batteries. However, when it shuts down, it stays off. Even if external power is re-applied, so that probably isn't it. (More of an FYI.)

The Magellan Meridian series switch over in an instant if you loose power, but what you get is an alarm stating you lost external power and you have to press the ESC key to clear.

On a fresh set of AA (non rechargable) batteries I get about 6-7 hours if I run the back lite on (when I am out at night) and about 8 if I do not.

09-04-2005	#1 (permalink)
theprez98 SpoonfeederExtraordinaire Join Date: Jan 2005 Location: Maryland Posts: 3,709	Another solution for your bag of tricks Here's one for your bag of tricks. My setup is as follows: Dell Inspiron 4100 running Auditor Security Collection (Kismet + GPSdrive), Proxim 8470-WD (Atheros chipset), Magellan Meridian Platinum GPS. I use a serial cable that runs from the back of the GPS to the serial port and also includes a lighter adapter to power the GPS. All of sudden, Kismet was reporting Lat/Longs of all zeroes and GPSdrive was reporting connection timed out to GPS. I confirmed the GPS was actually working and transmitting NMEA, no problem there. A cursory inspection of both the serial end of the cable and the GPS end of the cable found nothing amiss. I also inspected the serial port on the back of the laptop for bent/missing pins, still nothing. I pulled out the multimeter to run some tests on the cable to determine if that could shed any light on the problem. About that time, I found several small pieces lying on the floor: a screw top, metal tip, fuse, and spring. The screw top of the lighter adapter had come apart, and the tip, fuse, and spring had actually fallen out of the lighter adapter! I immediately replaced the spring, fuse and tip and screwed the top back on. My first inclination was that there wasn't any way that this could have been the source of the problem. But, I figured I might as well test it (and Dutch's prodding certainly helped). So, I re-connected the cable and of course, it worked immediately. Perhaps someone else can shed some light on the details of why the lighter adapter had anything to do with the laptop not receiving the GPS data. The only information I can find is that it might have something to do with the ground. Either way, it's another solution to add to your bag of tricks. __________________ :00475160 0E A6 AE A0 19 E3 A3 46 .......F :00475168 0D 65 17 0C 53 70 6F 6F .e..Spoo :00475170 6E 66 65 65 64 65 72 2E nfeeder. :00475178 45 78 74 72 61 6F 72 64 Extraord :00475180 69 6E 61 69 72 65 5D 3B inaire]; :00475188 8B 9E 92 5A FF 5D A6 F0 ...Z.]..

09-04-2005	#2 (permalink)
streaker69 Psychic Amish Stumbler Join Date: Jul 2004 Location: Virginville, BlueBall, Bird In Hand, Intercourse, Paradise, PA Posts: 12,239	Could be an odd power save mode. Turn off serial port when running on battery. __________________ Treat your gun like your genitals, only whip it out when it's absolutely necessary.

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