Virtual Fence - Anti Theft Device

SIM808 GSM :

• Supports Quad-band 850/900/1800/1900MHz, compatible with all 2G networks all around the world.

• Inner MT3337 GPS receiver, -165dBm precision, control on a same serial port.

• Earphone/ microphone outputs on a card or external 32-ohm speaker + supports voice calls with an electret microphone.

• Sending and receiving SMS.

• Sending and receiving GPRS data (TCP/IP, HTTP vb).

• UART communication with automatic baud rate settings.

• GPRS multi-slot class 12/10

• GPRS mobile station class B

• Comply with GSM phase 2/2 +

  Class 4 (2 W @ 850 / 900MHz)

  Class 1 (1 W @ 1800 / 1900MHz)

• Support low power consumption mode: 100mA @ 7V-GSM mode

• Support AT command control (3GPP TS 27.007,27.005 and SIMCOM enhanced AT Commands)

• Supports GPS satellite navigation technology

• Support LED status indicator: Power supply status, network status, and operating modes

• Working environment: -40 ℃ ~ 85 ℃

• 22 tracking/66 acquisition channel

• GPS L1 C/A code

• Precision: Tracking: -165dBm,

• Cold start: -148dBm

• Finding Location Time(typical): Cold start: 32sn, Hot start: 1sn, Warm start: 5sn

• Accuracy: ~2.5m

With all these features, it is nearly a handheld portable phone. Yes, you can make a phone call too :P

One grieving concern is, whether going ahead with a smaller size module would fit the portability requirements - Even if a SIM800 module was taken into consideration, for a prolonged secure network that requires more uptime it is a much safer option to go ahead with its successor. Hence, the SIM808 module was chosen for this project. Even though based on availability and price we can always go ahead with the SIM800.

Let us first understand the module and how to get started with a SIM module -

Hardware Side -

1. Make following connections > GND of both modules connected to each other.

2. (For PuTTY) TXD of SIM808 connect with TX1 (PIN 1) of Arduino UNO. Similarly RXD ->RX0.

3. (For Arduino) TXD of SIM808 connect with (PIN 10) of Arduino UNO. Similarly RXD ->11.

4. Connect the Arduino UNO to Arduino IDE and upload a default code that does not interface the serial monitor. Eg: Blink LED sketch.
5. Press Normal button for 2 seconds and leave - the Device will start after that. (Different from power sliding switch)

Software side (PuTTy) -

1. Install PuTTY Application software from https://www.putty.org/

2. Change 'Connection Type' to 'Serial'.

3. Enter Serial port on PuTTY. eg: COM8 > With baudrate as '9600'.

4. Click on 'Open' to open the serial terminal

Software side (Arduino IDE) -

Use the below code -

#include <SoftwareSerial.h>
SoftwareSerial mySerial(10, 11); 
void setup() {  
    Serial.begin(9600);  
    mySerial.begin(9600);
}
void loop() {  
    Serial.println("AT");  
    if (mySerial.available()) {	
        Serial.write(mySerial.read());  
    }  
    if (Serial.available()) {	
        mySerial.write(Serial.read());  
    }  
    delay(500);
}

Testing Commands -

• AT - Check serial communication with module | if no response recheck connections / redo connections / loose connection /module turned off
• AT+CMEE=1 - 1 to disable error &the 2 for verbose errors with error codes
• AT+CPIN? - Check SIM availability with module

# Make Phone Calls

• ATD9989758468; - Phone calls to the number - use Mic and Speaker jack for i/o
• ATH - End phone call
• ATA - Pick up phone call when serial monitor says ‘RING’ repeatedly
• AT+CLCC - Check caller number

# Make Text Messages

• AT+CSMP=17,167,0,0 - Avoid error messages or delivery of empty SMS
• AT+CMGF=1 - Text Mode
• AT+CMGS="+917002834895" - Send message to this number
  > Enter your message
  > //After pressing 'Enter' move to next line or/and Press Ctrl+Z to send the message
• AT+CMGS: 55 - Responses with the packet command after a few seconds to show that message was delivered.
• AT+CMGL = "ALL” - Read all messages

# For GPS Coordinates (GNS because using v2.0 of SIM808)

• AT+CGNSPWR = 1 - Turn on GPS module - use 0 to turn OFF
• AT+CGNSSEQ = "RMC" - Proper sequence of NMEA according to RMC
• AT+CGNSINF - Prints Time and GPS according to module - returns 0 if GPS not set. Returns 1 when outdoors for setting with GPS satellite

Code Breakdown

#include <SoftwareSerial.h>

SoftwareSerial mySerial(5, 6); 

It sets up a SoftwareSerial instance named mySerial using digital pins 5 (RX) and 6 (TX) on the Arduino, which will be used to communicate with the SIM808 module.

void(* resetFunc) (void) = 0;
void GPS_data();
void check_GPS();
void sendSMS();

char frame[256];

byte GNSSrunstatus;  
byte Fixstatus;           
char UTCdatetime[15];

char latitude[10];
float latitude_val;

char longitude[11];
float longitude_val;

long lat_val;
long lon_val;

long lat_high;
long lat_low;

long lon_high;
long lon_low;

int lat_check;
int lon_check;

char altitude[8];
char speedOTG[6];
char course[6];
char fixmode[1];
char HDOP[4];
char PDOP[4];
char VDOP[4];
char satellitesinview[2];
char GNSSsatellitesused[2];
char GLONASSsatellitesused[2];
char cn0max[2];
char HPA[6];
char VPA[6];

• Pre-declaration of Functions without function body, to inform the program about the existence of function, before defining, so as to manipulate the arrangement within the program.

• Global variables like altitude, speedOTG are to be used within the program, and since the device will run indefinitely, the values are most likely to get reset on setting up new locations as Geo-Fencing.

void setup() {
  Serial.begin(9600);
  mySerial.begin(9600);

  mySerial.println("ATr"); 
  updateSerial();
  mySerial.println("AT+CSQ"); 

  updateSerial();
  mySerial.println("AT+CCID"); 

  updateSerial();
  mySerial.println("AT+CPIN?"); 

  updateSerial();
  GPS_data(); 
  
  lat_high = lat_val + 900;
  lat_low = lat_val - 900;
  lon_high = lon_val + 900;
  lon_low = lon_val - 900;
}

• AT+CSQ - Returns the signal strength of the device.

• AT+CCID - Read SIM information, which returns the unique Integrated Circuit Card Identifier (ICCID) of the installed SIM card.

• AT+CPIN - Checks if the SIM is locked with a PUK code, or whether it is ready to use.

• Calling GPS_data() function to initialize the current location, as the center of the Geo-Fence

Next, set the fence around the center by selecting coordinates values with 300m-500m towards lat and long.

4. Hardware - Software Serial Interconnection

void updateSerial()
{
  delay(500);
  while (Serial.available()) 
  {
    mySerial.write(Serial.read());
  }
  while(mySerial.available()) 
  {
    Serial.write(mySerial.read());
  }
}

• mySerial.write(Serial.read()) : Forwards from Hardware Serial to Software Serial
• Serial.write(mySerial.read()) : Forwards from Software Serial received to Serial Port

void GPS_data(){
  mySerial.println("AT+CGNSPWR=1");
  updateSerial();
  mySerial.println("AT+CGNSSEQ="RMC"");
  updateSerial();
  mySerial.println("AT+CGNSINF");
  check_GPS();
}

• AT+CGNSPWR = 1 : Turns ON the SIMCOM module
• AT+CGNSSEQ=RMC : Configure the GPS module for settings (RMC - Time, date, position, course and speed data)
• AT+CGNSINF : GNSS navigation information parsed from NMEA sentences

void check_GPS(){

  ...
}

int8_t counter, answer;
  long previous;

  counter = 0;
  answer = 0;
  memset(frame, '