KR1 and GPSd Technical Discussion

tz1 · Posted: Tue Feb 21, 2006 12:50 pm Post subject:

4800 might not be supported, or stty may have a problem (or something else might grab /dev/ttyS1). I also may have different firmware. My firmware differs from that file.

tz1 · Posted: Tue Feb 21, 2006 12:54 pm Post subject:

A vanilla serial adapter to the phone port might make /dev/ttyUSB2 or USB3 work. It seems to want to recognize everything as a serial adapter. A garmin USB will probably not work unless it is recognized as a serial device (without any fancy module) and gpsd supports the garmin protocol. A plainer usb gps might work.

hxmiller · EVDO User Joined: 30 Jun 2005 Posts: 46

tz1 · Posted: Tue Feb 21, 2006 11:45 pm Post subject:

Apparently FTDI isn't vanilla.

It has to be looking for some kind of modem to see the phone.

I also found my laptop's USB will power the KR1 - I found an old adapter cable (I think for a USB digiter I may no longer have) that works.

I also found my cable for my etrex. Now if I can only get ttyS1 to cooperate. Maybe a look into some kernel source might be revealing.

ttyS0 will do 115200 or 4800 with a simple stty command.

Using the updated firmware, ttyS1 starts out - stty -a works but says something about IRQ3 - at 9600 baud.

From a clean boot, at the console, "cat /dev/ttyS1" will display the text output from my etrex (can't do nmea at 9600 baud). This is with a standard USB cable to the ttyS1 "diagnostic port" with the black wire to pin 5 and the green wire to pin 2 (white to pin 3 for completeness).

I may have to port a real stty, setserial, or something.

tz1 · Posted: Wed Feb 22, 2006 9:53 am Post subject:

I am watching NMEA sentences from my laptop telnetted to the KR1 on port 2947 now (I am indoors so it is not as interesting).

It doesn't seem stable, but the existing gpsd DOES change the baud rate to 4800 and otherwise works.

I used gpsd -D 3 -N /dev/ttyS1 and my special cable to the diagnostic port, but had to fiddle with the garmin (putting it in garmin dgps protocol for a moment) before it worked.

It may be eating too much cpu (top shows 98% - ouch, I need to put it on a diet...). The processor also has no floating point but gpsd uses it extensively.

With this success, I may be able to go back to my very lightweight gpsmux which can at least send the raw NMEA over the air.

tz1 · Posted: Wed Feb 22, 2006 10:39 am Post subject:

My gpsmux program just reads ttyS1 and echoes it to up to 8 connections on port 2947 (same as gpsd with the R command).

binary: http://homepage.mac.com/tz1/.public/gpsmux

Source upon request, but I'll be tweaking it, maybe to be exactly like a gpsd that only supports the "r" command, or I will have to look at gpsd forwarding (have real gpsd run locally, but pull the nmea over the net).

Less than 1% cpu.

Apparently on ttyS1 you only get one shot at opening it and setting the baud rate after reset. But it does work. I got 4800 baud NMEA sentences over telnet.

1. You need to upgrade to the "production" firmware, at least if your KR1 runs diagnostic since it will do the baud rate set as part of the bootup. Note I had problems with firmware upgrades.

2. You still need a console, if only to do "chmod +x gpsmux" and "gpsmux &" to start things (using tftp to upload gpsmux to /var/tmp). At least until this could be installed in the firmware.

3. You need the special USB to male cable described in an earlier post. (USB standard colors) Green to pin 2, white to pin 3, black to pin 5.

hxmiller · EVDO User Joined: 30 Jun 2005 Posts: 46

tz1 · Posted: Thu Feb 23, 2006 7:00 am Post subject:

Some applications might be able to use GPSMUX directly - some just connect and give the "R" command to get the raw data streams.

For others, you can compile gpsd on a PC and point it at a pipe, e.g.

mkfifo /tmp/gpsdata
gpsd /tmp/gpsdata &
telnet mykr1hostname 2947 >/tmp/gpsdata &

tz1 · Posted: Fri Feb 24, 2006 8:12 pm Post subject:

One more thing about starting up gpsmux - you don't have to use tftp if the internet connection is up.

Set the serial port and you can just send the following commands:

wget http://homepage.mac.com/tz1/.Public/gpsmux
chmod 755 gpsmux
./gpsmux &

It will pull the program from my .mac homepage, and since it is only 9K it doesn't take much time.

tz1 · Posted: Fri Feb 24, 2006 9:02 pm Post subject:

OOPs, prefix the three commands with this one:

cd /var/tmp

tz1 · Posted: Tue Feb 28, 2006 1:09 pm Post subject: Success - part 1

gpsmux lives, out of power-up.

Of the 6 programs mentioned on the gpsd site, only kismet can't handle raw nmea (though a while ago I wrote a raw nmea patch). gpsdrive works fine.

I have my gps16 connected to the KR1 and can get the NMEA streams wirelessly or via the internet.

I'm still making adjustments to the image (putting my busier busybox with 100+ commands v.s. theirs in, adding socat), but what I have now works.

I may also try to do a gpsd-lite. The current verison is a kitchen sink program, and the earlier ones only implemented a few commands (which I think I can reduce so as not to use floating point or excessive CPU).

I will do something more for an announcement when there is an official firmware update for the KR1, and/or when I finish stabilizing it.

tz1 · Posted: Sun Mar 05, 2006 12:04 pm Post subject:

I was successfully able to track my drive with the KR1 in my car on my home computer (after some tweaking to handle disconnects in my map program - this isn't perfect yet but functions).

The USB port on the KR1 supplies enough power for my GPS, so I've built a dual USB connector (with a bit of mounting tape between), so the power comes from the phone port, and the serial attaches to the diagnostic port.

The only other problems come from trying to power the KR1 with backup. The diode-drop is too much, but I don't want to backfeed.

Michael · Posted: Sun Mar 05, 2006 12:10 pm Post subject:

Lets email today or tomorrow.

I have GoogleMaps integration working with a Stompbox and it should work with the GPSd running on a KR1, so lets test.
_________________
EVDO :: EVDO News :: EVDO Antennas :: Buy Verizon :: Buy Sprint :: EVDO Amplifier

morpheus · EVDO User Joined: 16 Jan 2006 Posts: 42

tz1 · Posted: Thu Mar 09, 2006 6:04 pm Post subject:

I am starting to get statistics and signal strength (and EVDO v.s. 1xRTT), at least for the KPC650. Since I'm right on the edge of EVDO service, as I watch see all the information from the card, it explains exactly what I am seeing with regards to throughput.

(Note that this uses the control port so works while connected)

I haven't decoded everything yet and the code is unstable, but it does return useful data.

I'll see if I can integrate that too into the software, at least for KPC650 cards.