Grove - GPS
Introduction
3.3V 5.0V UART
This Grove - GPS module is a cost-efficient and field-programmable gadget armed
with a SIM28 (u-blox 6 is the old version) and serial communication configuration. It
features 22 tracking / 66 acquisition channel GPS receiver. The sensitivity of tracking
and acquisition both reach up to -160dBm, making it a great choice for personal
navigation projects and location services, as well as an outstanding one among
products of the same price class.
Features
• Supports NMEA and u-blox 6 protocols. ( Till Jan,10 2014, after that SIM28 instead)
• Low power cons umptio n
• Baud r ates configurable
• Grove comp at ible interface
Tip
Parameter
Range/Value
Input Voltage
3.3/5V
BaudRate
4800 - 57600(u-blox version)
BaudRate
9600 - 115200(SIM28 version)
Default BaudRate
9600
Raspberry
Pi
LinkIt
ONE
More details about Grove modules please refer to Grove System
Specifications
Platforms Supported
Arduino Wio BeagleBone
Caution
The platforms mentioned above as supported is/are an indication of the module's hardware or theoritical compatibility. We only
provide software library or code examples for Arduino platform in most cases. It is not possible to provide software library /
demo code for all possible MCU platforms. Hence, users have to write their own software library.
Getting Started
Following documents help in getting the user started with Grove.
• to Grove system
Demos
With Arduino
This sample simply reads from the GPS using software serial and sends it back out
on the serial port.
1. Connect the Grove-GPS to Digital I/O 2 on the Grove - Base Shield using a Grove
Universal 4 pin cable.
2. Upload the code below.
// link between the computer and the SoftSerial Shield
//at 9600 bps 8-N-1
//Computer is connected to Hardware UART
//SoftSerial Shield is connected to the Software UART:D2&D3
#include <SoftwareSerial.h>
SoftwareSerial SoftSerial(2, 3);
unsigned char buffer[64]; // buffer array for data receive over serial port
int count=0; // counter for buffer array
void setup()
{
SoftSerial.begin(9600); // the SoftSerial baud rate
Serial.begin(9600); // the Serial port of Arduino baud rate.
}
void loop()
{
if (SoftSerial.available()) // if date is coming from software serial port
==> data is coming from SoftSerial shield
{
while(SoftSerial.available()) // reading data into char array
{
buffer[count++]=SoftSerial.read(); // writing data into array
if(count == 64)break;
}
Serial.write(buffer,count); // if no data transmission ends, write buffer to
hardware serial port
clearBufferArray(); // call clearBufferArray function to clear the
stored data from the array
count = 0; // set counter of while loop to zero
}
if (Serial.available()) // if data is available on hardware serial port ==> data
is coming from PC or notebook
SoftSerial.write(Serial.read()); // write it to the SoftSerial shield
}
void clearBufferArray() // function to clear buffer array
{
for (int i=0; i<count;i++)
{
buffer[i]=NULL;
} // clear all index of array with command NULL
}
• Install u-center. Upload the code below to your Arduino/Seeeduino and then open
u-center.
1. Click Receive r -> Port and select the COM port that the Ardui no is using.
2. Click Receive r -> Baudrate and make sure 9600 is selected.
3. Click View -> Text Console and you should get a window that will stream NMEA data.
4. Open the serial monitor,You can see as show below:
• To View data in Google Earth:
1. Click File -> Database Export -> Google Earth KML
2. This should launch Google Earth with the history that was captured by u-center.
3. Alternatively, data can be recorded by pressing the red circle on the toolbar which will
then ask you where you want to save the record.
4. When you have captured enough data, click the black square to stop recording.
5. You can then convert the .ubx file generated to KML by using uploading the ubx file
to GPSVisualizer.
With Rasp ber r y Pi
1.You need a Raspberry Pi and a GrovePi or GrovePi+.
2.You should have completed configuring the development environment, otherwise
follow here.
3.Connection
• Plug Grove GPS into grovepi socket RPISER.
4.Navigate to the demos’ directory:
cd yourpath/GrovePi/Software/Python/
• To see the code
nano grove_gps.py # "Ctrl+x" to exit #
import serial, time
import smbus
import math
import RPi.GPIO as GPIO
import struct
import sys
ser = serial.Serial('/dev/ttyAMA0', 9600, timeout = 0) #Open the serial port at 9600 baud
ser.flush()
class GPS:
#The GPS module used is a Grove GPS module http://www.seeedstudio.com/depot/Grove-GPS-p-959.html
inp=[]
# Refer to SIM28 NMEA spec file http://www.seeedstudio.com/wiki/images/a/a0/SIM28_DATA_File.zip
GGA=[]
#Read data from the GPS
def read(self):
wh ile True:
GPS.inp=ser.readline()
if GPS.inp[:6] =='$GPGGA': # GGA data , packet 1, has all the data we need
break
time.sleep(0.1)
tr y:
ind=GPS.inp.index('$GPGGA',5,len(GPS.inp)) #Sometimes multiple GPS data packets come
into the stream. Take the data only after the last '$GPGGA' is seen
GPS.inp=GPS.inp[ind:]
ex cept ValueError:
print ""
GPS.GGA=GPS.inp.split(",") #Split the stream into individual parts
re turn [GPS.GGA]
#Split the data into individual elements
def vals(self):
time=GPS.GGA[1]
lat=GPS.GGA[2]
lat_ns=GPS.GGA[3]
long=GPS.GGA[4]
long_ew=GPS.GGA[5]
fix=GPS.GGA[6]
sats=GPS.GGA[7]
alt=GPS.GGA[9]
re turn [time,fix,sats,alt,lat,lat_ns,long,long_ew]
g=GPS()
f=open("gps_data.csv",'w') #Open file to log the data
f.write("name,latitude,longitude\n") #Write the header to the top of the file
ind=0
while True:
try:
x=g.read() #Read from GPS
[t,fix,sats,alt,lat,lat_ns,long,long_ew]=g.vals() #Get the individial values
pr int "Time:",t,"Fix status:",fix,"Sats in
view:",sats,"Altitude",alt,"Lat:",lat,lat_ns,"Long:",long,long_ew
s=str(t)+","+str(float(lat)/100)+","+str(float(long)/100)+"\n"
f.write(s) #Save to file
time.sleep(2)
except IndexError:
pr int "Unable to read"
except KeyboardInterrupt:
f.close()
pr int "Exiting"
sys.exit(0)
5.Run the demo.
sudo python grove_gps.py
6.Result
Note
GPS is better used outdoors. It is recommended to put your raspberry pi outside the window
or any place outdoors.
SIM28 module Note:
1. GPS Bee has change the module as SIM28 which the same footprint as origin version.
2. You should use “SIMCom GPS DEMO” tools to receive SIM28 module data.
3. Open SIMCom_GPS_DEMO tools, go to Module->properties->module->select
SIM28.
4. Open SIMCom_GPS_DEMO tools, go to Module->connect. Select the serial port
which the GPS module used.
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