DFM-09 Modification to GPS-Mouse

The DFM-09 is a series of small single-board Radiosonde's developed by Graw to carry out meteo soundings.
Inside houses a GPS Jupiter Telit JN3 or on older versions SL869 V2 is also used.
If the job is done, they are useless..
But they can be recycled to GPS Mouse.

Hardware Details

DFM-09 Details: https://www.gruan.org/instruments/radiosondes/sonde-models/graw-dfm-09/    

Telit Jupiter JN3 Details: https://www.telit.com/m2m-iot-products/positioning-timing-modules/positioning-gps-jupiter-n

GPS chips are often used on Radiosonde's to get a accurate position.
The SL869 version operates at NMEA 19200 baudrate if the platine stays intact.

A shorter modified SL869 version without controller will operate at NMEA 9600 Baud.
As the JN3 shorter version uses SIRF at 9600Baud.

Needed stuff

DFM-09.
USB-TTL converter.
Some wires.
Soldering tools.

NMEA 19200 Baud SL 869V2 Modification

Remove the Batteries.
White cable on the left should be removed.
Sensors and 400MHz transmit antenna on the right from the power button.

And solder TTL-USB converter on 4 tiny pins bottom right from JN3 GPS module:

1: GND -

2: RX

3: TX

4: +3.3V

Build together ->

NMEA 9600 Baud JN3/SL869 V2 Modification

For this modification, we did shorten the platine by cutting of just before the 4 tiny connection holes.

And solder TTL-USB converter on 4 tiny pins bottom right from JN3 GPS module:

1: GND -

2: RX

3: TX

4: +3.3V

Some Glue to tight up the wires.

Ready :)

Windows NMEA Mode SL869 V2

Place on a site with some good view.

Connect with USB cable to computer.

Select COM Port (most probaly Prolific driver is needed on Windows) start GPS application and choose 19200 baud.

Some Example programs:

DFM-09 works in NMEA 19200 Baud mode.

Sync time for Sat's with NMEA Time.
It's not possible to use Sirf mode.

Windows Using Sirf Mode JN3

                                                       

Download and start SirfDemo select COM Port (most probaly Prolific driver is needed on Windows) and use 9600 Baud to connect with the JN3 Short version.

JN3 starts itself in Binary Sirf mode.

From action menu choose Switch to NMEA Protocol.

Choose a desired Baudrate.

DFM-06 works in NMEA 4800 Baud mode.

Can use any GPS Application know.

But remember to follow whole procedure again when disconnecting the GPS Mouse, it will start again in Binairy Sirf Mode..

A batch file can be made for auto startup GPS mouse in NMEA Mode .

Example Com:1 4800 Baud:

@echo off

echo Switching DFM to GPS mouse.

mode com1 baud=9600 parity=n data=8 stop=1

copy sirfbinary2nmea.txt com1:

echo  4800 baud.

Windows NMEA Mode JN3

Select COM Port (most probaly Prolific driver is needed on Windows) start GPS application and choose 9600 baud.

Some programs cannot readout the location with this modification with exception of SAS-Planet.
Not all TPV's are send out.
This can be manually done with a terminal program or batch files if preferred.

$$PMTK353,1,0,0,0,0*2A$0D$0A

Baudrate change: $PMTK251,baud*checksum
Refresh rate change: $PMTK220,rate[ms]*checksum ($PMTK220,200*2F = 5Hz etc...)
Turn on Glonass & GPS: $PMTK353,1,1,0,0,0

Its not possible to use Sirf mode.

Linux NMEA/Sirf

In Linux no drivers are needed to install.

For Sifrmode on the 9600 JN3 Short Version a script can be made:

sirfbinary2nmea.txt

Make dfm.sh

#!/bin/sh

dmesg | grep ttyUSB0

echo "Switch DFM06 from binary 2 NMEA mode..."

cd /home/gps

sudo stty -F /dev/ttyUSB0 speed 9600

echo "Insert sirfbinary2nmea..."

cat sirfbinary2nmea.txt > /dev/ttyUSB0

echo "Switch to 4800 Baud..."

sudo stty -F /dev/ttyUSB0 speed 4800

echo "Done DFM on 4800 Baud"

Before make some sudo chown -R <username:username> /dev/ttyUSB0

You can use GPSD with some build in apps or use FoxtrotGPS/Viking.

gpsd /dev/ttyUSB0

NMEA Mode:
dmesg | grep ttyUSB

xgps /dev/ttyUSB0

cgps -s

gpsmon /dev/ttyUSB0

Make it work in Wine

Note: The shorter JN3 9600Baud version does not need the command for position when using GPSD the position shows fine.