Interfacing Gsm/Gprs/Gnss/Bluetooth Hat With Raspberry Pi 3

As in our previous posts, we make a clear picture about interfacing the GPS, GSM/GPRS modules with Raspberry pi individually. So now its time to integrate these clustered functions in to a single device suited for Raspberry pi. A new module has been introduced with these appended functionalities and it is named as per its properties, Gsm/Gprs/Gnss/Bluetooth Hat.

Communication system has been attained at its prime level by introducing this module as it prompts the IoT applications along with the location access. All the upcoming electronic systems will be accomplished with this communication schemes. The module will be highlighted when it is being interfaced with a Raspberry pi, as it can easily derive its functionalities. Eventually we can build our own mobile or tablet devices by the integration of these modules or can even up to more.

Here we brought the knowledge of basic interfacing between a Raspberry Pi3 and the HAT module. As in the HAT module, there are two ways for making the connections.

USB interfacing
GPIO interfacing

Here we make use of a micro USB cable for connecting Raspberry Pi with the HAT module that in-turn provides the suitable power and establish a serial communication.

SIM 868 module is being used in this device which is a complete Quad-Band GSM/GPRS module which combines GNSS technology for satellite navigation. In the left side of the module you can see a yellow jumper connected to the suitable pins. There are four pairs of pins in which the jumpers must be shorted to make three terminal pairs (A,B,C).

A: control the SIM868 through USB TO UART

B: control the SIM868 through Raspberry Pi

C: access Raspberry Pi through USB TO UART

Here we make use of A terminal, ie the jumpers must be connected vertically in the first two pins as shown in the figure given below.

Working

Power on the raspberry pi module with raspbian OS installed on it. Connect the hat module to the raspberry pi through USB as shown in the first figure.
Insert a sim card to the HAT module to perform GSM operations.
After connecting the USB, the pwr led will be in an on state. Press the PWRKEY for 3 seconds and remove it. The STA LED (status) will also be ina an on state.
The NET led will blink in a continuous manner and the after obtaining the range for sim card, the blinking rate will be reduced.

Programming

Here we are giving two programs in python for sending messages and for getting the GPS data on Raspberry Pi.

Code for sending messages using Gsm/Gprs/Gnss/Bluetooth Hat

import serial
import RPi.GPIO as GPIO      
import os, time

from random import randrange
GPIO.setmode(GPIO.BOARD)    

# Enable Serial Communication
port = serial.Serial("/dev/ttyUSB0", baudrate=115200, timeout=1)

# Transmitting AT Commands to the Modem
# '\r\n' indicates the Enter key
port.write('AT'+'\r\n')
rcv = port.read(10)
print rcv
time.sleep(.1)

port.write('ATE0'+'\r\n')      # Disable the Echo
rcv = port.read(10)
print rcv
time.sleep(.1)

port.write('AT+CMGF=1'+'\r\n')  # Select Message format as Text mode
rcv = port.read(10)
print rcv
time.sleep(.1)

port.write('AT+CNMI=2,1,0,0,0'+'\r\n')   # New SMS Message Indications
rcv = port.read(10)
print rcv
time.sleep(.1)

# Sending a message to a particular Number
port.write('AT+CMGS="Mob. No."'+'\r\n')
rcv = port.read(10)
print rcv
time.sleep(.1)

port.write('Hello'+'\r\n')  # Message
rcv = port.read(10)
print rcv

port.write("\x1A") # Enable to send SMS
for i in range(10):
    rcv = port.read(10)
    print rcv

import serial

import RPi.GPIO as GPIO

import os, time

from random import randrange

GPIO.setmode(GPIO.BOARD)

# Enable Serial Communication

port = serial.Serial("/dev/ttyUSB0", baudrate=115200, timeout=1)

# Transmitting AT Commands to the Modem

# '\r\n' indicates the Enter key

port.write('AT'+'\r\n')

rcv = port.read(10)

print rcv

time.sleep(.1)

port.write('ATE0'+'\r\n') # Disable the Echo

rcv = port.read(10)

print rcv

time.sleep(.1)

port.write('AT+CMGF=1'+'\r\n') # Select Message format as Text mode

rcv = port.read(10)

print rcv

time.sleep(.1)

port.write('AT+CNMI=2,1,0,0,0'+'\r\n') # New SMS Message Indications

rcv = port.read(10)

print rcv

time.sleep(.1)

# Sending a message to a particular Number

port.write('AT+CMGS="Mob. No."'+'\r\n')

rcv = port.read(10)

print rcv

time.sleep(.1)

port.write('Hello'+'\r\n') # Message

rcv = port.read(10)

print rcv

port.write("\x1A") # Enable to send SMS

for i in range(10):

rcv = port.read(10)

print rcv

Code for getting GPS data using Gsm/Gprs/Gnss/Bluetooth Hat

Before running the code for GPS a GNSS antenna connector must be connected to the Hat module. Connect a GPS antenna to that connector and place the antenna projected to clear sky for GPS initialization.As shown in the figure above make the connections, and run the program given below in python.

#!/usr/bin/python

import serial
import time
from decimal import *
from subprocess import call

def find(str, ch):
    for i, ltr in enumerate(str):
        if ltr == ch:
            yield i

# Enable Serial Communication
port = serial.Serial("/dev/ttyUSB0", baudrate=115200, timeout=1)
# Transmitting AT Commands to the Modem
# '\r\n' indicates the Enter key

port.write('AT'+'\r\n')			
rcv = port.read(100)
print rcv
time.sleep(.1)

port.write('AT+CGNSPWR=1'+'\r\n')    	 	# to power the GPS
rcv = port.read(100)
print rcv
time.sleep(.1)

port.write('AT+CGNSIPR=115200'+'\r\n') # Set the baud rate of GPS
rcv = port.read(100)
print rcv
time.sleep(.1)

port.write('AT+CGNSTST=1'+'\r\n')    # Send data received to UART
rcv = port.read(100)
print rcv
time.sleep(.1)

port.write('AT+CGNSINF'+'\r\n')   	# Print the GPS information
rcv = port.read(200)
print rcv
time.sleep(.1)
ck=1
while ck==1:
    fd = port.read(200)		# Read the GPS data from UART
    #print fd
    time.sleep(.5)
    if '$GNRMC' in fd:		# To Extract Lattitude and 
        ps=fd.find('$GNRMC')		# Longitude
        dif=len(fd)-ps
        if dif &gt; 50:
            data=fd[ps:(ps+50)]
            print data
            ds=data.find('A')		# Check GPS is valid
            if ds &gt; 0 and ds &lt; 20:
                p=list(find(data, ","))
                lat=data[(p[2]+1):p[3]]
                lon=data[(p[4]+1):p[5]]

# GPS data calculation

                s1=lat[2:len(lat)]
                s1=Decimal(s1)
                s1=s1/60
                s11=int(lat[0:2])
                s1 = s11+s1

                s2=lon[3:len(lon)]
                s2=Decimal(s2)
                s2=s2/60
                s22=int(lon[0:3])
                s2 = s22+s2

                print s1
                print s2

#!/usr/bin/python

import serial

import time

from decimal import *

from subprocess import call

def find(str, ch):

for i, ltr in enumerate(str):

if ltr == ch:

yield i

# Enable Serial Communication

port = serial.Serial("/dev/ttyUSB0", baudrate=115200, timeout=1)

# Transmitting AT Commands to the Modem

# '\r\n' indicates the Enter key

port.write('AT'+'\r\n')

rcv = port.read(100)

print rcv

time.sleep(.1)

port.write('AT+CGNSPWR=1'+'\r\n') # to power the GPS

rcv = port.read(100)

print rcv

time.sleep(.1)

port.write('AT+CGNSIPR=115200'+'\r\n') # Set the baud rate of GPS

rcv = port.read(100)

print rcv

time.sleep(.1)

port.write('AT+CGNSTST=1'+'\r\n') # Send data received to UART

rcv = port.read(100)

print rcv

time.sleep(.1)

port.write('AT+CGNSINF'+'\r\n') # Print the GPS information

rcv = port.read(200)

print rcv

time.sleep(.1)

ck=1

while ck==1:

fd = port.read(200) # Read the GPS data from UART

#print fd

time.sleep(.5)

if '$GNRMC' in fd: # To Extract Lattitude and

ps=fd.find('$GNRMC') # Longitude

dif=len(fd)-ps

if dif > 50:

data=fd[ps:(ps+50)]

print data

ds=data.find('A') # Check GPS is valid

if ds > 0 and ds < 20:

p=list(find(data, ","))

lat=data[(p[2]+1):p[3]]

lon=data[(p[4]+1):p[5]]

# GPS data calculation

s1=lat[2:len(lat)]

s1=Decimal(s1)

s1=s1/60

s11=int(lat[0:2])

s1 = s11+s1

s2=lon[3:len(lon)]

s2=Decimal(s2)

s2=s2/60

s22=int(lon[0:3])

s2 = s22+s2

print s1

print s2

Python Shell Results

Note: To obtain an internet connection through this hat module, Please refer the link given below;

https://wiki.rhydolabz.com/?p=16325.(Use /dev/ttyUSB0 for serial communication).

Shop With US:

Click here to buy Gsm/Gprs/Gnss/Bluetooth Hat For Raspberry Pi from rhydoLABZ.
Click here to buy Raspberry Pi 3 Starter Kit from rhydoLABZ.

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