This document describes creating an easy GPS tracker using an Arduino and Python. The goal is to develop a low-cost system with wide range to locate autonomous underwater vehicles (AUVs). It discusses using an Arduino with a GPS module to get location data and transmitting it via XBee radios. Python libraries are used to program the Arduino and process NMEA GPS strings. A graphical user interface (GUI) is created with PyQt to display the vehicle's position on georeferenced maps. Future plans include optimizing the system, testing coverage range, conducting field tests, adding bearing and range calculations between devices, and developing AUV utilities that use XBee communications.

1. Introduction
Arduino
GPS
Maps
GUI
Python and Arduino
Easy GPS Tracker using Arduino and Python
Núria Pujol Vilanova
Unitat de Tecnologia Marina (CMIMA-CSIC)
npujol@utm.csic.es
nuriapujolvilanova@gmail.com
16. January 2014
Future

2. Introduction
Arduino
GPS
Maps
What is my spech about?
1
2
3
4
5
Arduino
Xbee communications
NMEA strings
Georefed image
GUI using PyQt
GUI
Future

3. Introduction
Arduino
GPS
Maps
GUI
What problem we want to solve?
Main objective
Looking for a low cost and wide range system to locate AUV.
GPRS systems coverage problems far from coast
Iridium satellite communication costs
Future

4. Introduction
Our Solution
Arduino
GPS
Maps
GUI
Future

5. Introduction
Arduino
GPS
Maps
GUI
Arduino Family
ARDUINO UNO
CPU Speed: 16MHZ
Analog IN: 6
Digital I/O: 14
UART: 1
Flash: 32Kb
ARDUINO MEGA
CPU Speed: 16MHZ
Analog IN: 16
Digital I/O: 54
UART: 4
Flash: 128Kb
Future

6. Introduction
Arduino
GPS
Xbee Devices
ZIGBEE
Freq: 2.4GHz
Power OUT: 63mW*
Max. Range: 3.2Km
RF Data rate: 250 Kbps
802.11bgn ("Wifi")
Freq: 2.4GHz
Power OUT: 16 dBm
Max. Range: 300m
RF Data rate: 65 Mbps
"PROPRIETARY"
Freq: 868MHz
Power OUT: 350mW
Max. Range: 40Km
RF Data rate: 24 Kbps
* 10mW limited in most EU
Maps
GUI
Future

7. Introduction
Arduino
GPS
Maps
How can I program my Arduino?
Arduino IDE
Classical way to program your Arduino
Using Python Libraries:
Python Arduino Prototyping, Pyduino, Pyfirmata,etc.
PyMite (Python-on-chip)
GUI
Future

8. Introduction
Arduino
GPS
Maps
How can I configure Xbee comunication?
Manufacturer software (X-CTU)
Moltosenso Network Manager
Serial Port (pyserial)
GUI
Future

9. Introduction
Arduino
GPS
Maps
GUI
Pyserial example using AT commands
>>> import serial
>>> ser = serial . Serial ( ’/ dev / ttyUSB0 ’ , baudrate =9600)
>>> ser . write ( ’ +++ ’)
>>> ser . write ( ’ ATID r ’)
>>> ser . read (8)
’ OK r7FFF r ’
>>> ser . write ( ’ +++ ’)
>>> ser . write ( ’ ATID 7 FF1 r ’ ’)
>>> ser . read (8)
’ OK r7FF1 r ’
>>> ser . write ( ’ +++ ’)
>>> ser . write ( ’ ATRE r ’)
>>> ser . write ( ’ ATCN r ’)
Future

10. Introduction
Arduino
GPS
Maps
GUI
Future
Programing example with Arduino IDE
# include < SoftwareSerial .h >
# define rxPin 9
# define txPin 8
SoftwareSerial gps = SoftwareSerial ( rxPin , txPin );
* VARIABLES *
void setup (){
pinMode ( rxPin , INPUT );
pinMode ( txPin , OUTPUT );
gps . begin (4800);
Serial . begin (9600);
delay (1000);
}

11. Introduction
Arduino
GPS
Maps
Programing example with Arduino IDE
void loop (){
byteGPS = 0;
byteGPS = gps . read ();
while ( byteGPS != ’$ ’ ){
byteGPS = gps . read ();
}(*)
byteGPS = gps . read ();
if ( byteGPS == ’G ’ ){ (*)
while ( byteGPS != ’* ’)
{
byteGPS = gps . read ();
GPS [ i ] = byteGPS ;
i ++;
}(*)
while (j < i ){
Serial . write ( char ( GPS [ j ]));
j ++;
}
Serial . println ();
}
}
(*) Missing lines of code
GUI
Future

12. Introduction
Arduino
GPS
Maps
Programing example with Python
from arduino import Arduino
import time
b = Arduino ( ’/ dev / ttyUSB0 ’)
pin = 9
# declare output pins as a list / tuple
b . output ([ pin ])
for xrange (10):
b . setHigh ( pin )
time . sleep (1)
print b . getState ( pin )
b . setLow ( pin )
print b . getState ( pin )
time . sleep (1)
b . close ()
https://github.com/vascop/Python-Arduino-Proto-API-v2/
GUI
Future

13. Introduction
Arduino
GPS
Maps
GUI
Future
After programing what we get?
>>> import serial
>>> from serial . tools import list_ports
>>> for port in list_ports . comports ():
...
print port
...
( ’/ dev / ttyUSB0 ’ ,... , ’ VID : PID =0403:6001 SNR = A9014UV2 ’)
( ’/ dev / ttyACM0 ’ ,... , ’ VID : PID =2341:0043 SNR = 8 5 2 3 5 3 5 3 1 3 7 3 5 1 1 1 8 1 1 2 ’)
>>> ser = serial . Serial ( ’/ dev / ttyUSB0 ’ ,9600)
>>> ser . inWaiting ()
243
>>> ser . readline ()
’ $GPGGA ,203156.000 ,4122.5905 , N ,00208.1725 , E ,...*5 r r n ’

14. Introduction
Arduino
GPS
Maps
GUI
NMEA Strings
GPGGA,203156.000,4122.5950,N,00208.1621,E,1,05,1.7,-21.8,M,51.0
NMEA to Decimal conversion
LAT: 4122.5950 N(41o 22.5950’ N)→41+(22.5950/60)=41.376583 N
LON: 00208.1621 E(2o 08.1621’ E)→2+(0.81621/60)=2.136035 E
Decimal to UTM conversion
def from_latlon ( latitude , longitude )
def LLtoUTM ( ReferenceEllipsoid , Lat , Long )
Future

15. Introduction
Arduino
GPS
Maps
Georefed images formats
TIFF + TFW ⇐⇒ GeoTIFF
Using a .tif file and a .tfw
Geotiff (embedded georeferencing information)
Where to obtain this files for free?
Institut Cartogràfic de Catalunya
Centro Nacional de Información Geográfica
GUI
Future

16. Introduction
Arduino
GPS
Georefed images formats
exemple.tfw
0.93 187659192 3412
0.00 000000000 0000
0.00 000000000 0000
-0.931876591923412
41 4 6 8 5 . 6 8 3 8 9 8 5 8 0 1 4 0 0 0 0
4570442.677152497700000
Maps
GUI
Future

17. Introduction
Arduino
GPS
Maps
GUI
Future
How to plot a GeoTIFF?
from osgeo import gdal
import matplotlib . pyplot as plt
gtif = gdal . Open ( ’ canal . tif ’)
gtif . G et P r o j e c t i o n R e f ()
gtif_array = gtif . ReadAsArray ()
tfw = gtif . G et G eo Tr a ns f or m ()
A ,D ,B ,E ,C , F = tfw [1] , tfw [2] , tfw [4] , tfw [5] , tfw [0] , tfw [3]
L = gtif . RasterXSize
H = gtif . RasterYSize
BLX , BLY , TRX , TRY =C , F , C +( L * A ) , F +( H *( E ))
extent =[ BLX , TRX , TRY , BLY ]
fig = plt . figure ()
axes = fig . add_subplot (111)
axes . t i c k l a b e l _ f o r m a t ( useOffset = False , axis = ’ both ’)
plt . imshow ( gtif_array [:3 ,: ,:]. transpose ((1 ,2 ,0)) , extent = extent )
plt . show ()

18. Introduction
Arduino
GPS
Maps
GUI
How to plot a TIFF?
import matplotlib . pyplot as plt
twf_values =[]
file = open ( ’ c a na l_ E TR 89 _ H3 1 . tfw ’ , " r " )
for line in file :
twf_values . append ( float ( line ))
A , D , B , E , C , F = twf_values
file . close ()
file_im = plt . imread ( ’ ca na l _E T R8 9_ H 31 . tif ’ , " r " )
L = len ( file_im [1 , :])
H = len ( file_im [: , 1])
BLX , BLY , TRX , TRY =C , F , C +( L * A ) , F +( H *( E ))
fig = plt . figure ()
axes = fig . add_subplot (111)
axes . t i c k l a b e l _ f o r m a t ( useOffset = False ,
axis = ’ both ’)
plt . imshow ( file_im , extent =[ BLX , TRX , TRY , BLY ])
plt . show ()
Future

19. Introduction
Obtained Plot
Arduino
GPS
Maps
GUI
Future

20. Introduction
Arduino
GPS
Maps
Adding GUI
Eric Python IDE
GUI
Future

21. Introduction
Arduino
GPS
Maps
Adding GUI
Qt 4 Designer
GUI
Future

22. Introduction
Final Result
Arduino
GPS
Maps
GUI
Future

23. Introduction
Arduino
GPS
Future plans
Optimization
Coverage range testing
Field Tests
Get range and bearing
AUV utilities using Xbee
Maps
GUI
Future

24. Introduction
Arduino
GPS
Maps
QUESTIONS?
GUI
Future