Hello,
I recently made a GPS tracker using Ublox Neo-6M gps module, A6 GSM Module and Atmega328P. The device is working fine but after few hours, sometimes after 2 days the device stops transmitting data, when i try calling the sim card it get through and i can hear it ring, but somehow the data is no transmitted. Upon disconnecting from power and reconnecting the device start sending data again and stops after a while, so i added a transistor to automatically power down the GSM module if the velocity drop to zero and switch on if the velocity climb above a particular value, however this do not work either. I have applied AES encryption to the data, i don’t know whether its causing the problem or not. I will post the code below, it would be really grateful if anyone could point out whats wrong with the code.
#include <SoftwareSerial.h>
#include <TinyGPS.h>
#include <AES.h>
#include <Base64.h>
#include <String.h>
SoftwareSerial SIM900(7, 8);
int gsm = 4;
int gps = 5;
int count = 0;
float velocity = 0;
float flat = 0;
float flon = 0;
bool gsmOFF = false;
void setup()
{
pinMode(gps, OUTPUT);
pinMode(gsm, OUTPUT);
digitalWrite(gsm, HIGH);
digitalWrite(gps, HIGH);
}
void loop()
{
String ndata = gpsData();
if (velocity < 7)
{
if (count < 6){
count = count + 1;
}
if (count == 5)
{
String data = aesEncryptedData(ndata);
data = "GET http://******************************************+data+ "\r\n\x1A";
sendData(data);
digitalWrite(gsm, LOW);
gsmOFF = true;
}
}
else {
if (gsmOFF) {
digitalWrite(gsm, HIGH);
delay(20000);
gsmOFF = false;
String data = aesEncryptedData(ndata);
data = “GET http://”******************************************" + data + “\r\n\x1A”;
sendData(data);
}
count = 0;
}
if (!gsmOFF) {
String data = aesEncryptedData(ndata);
data = “GET http://******************************************” + data + “\r\n\x1A”;
sendData(data);
}
}
String gpsData()
{
SoftwareSerial ss(3, 2);
TinyGPS gps;
unsigned long age;
String getStr;
ss.begin(9600);
for (unsigned long start = millis(); millis() - start < 1000;) {
if (ss.available()) {
char c = ss.read();
gps.encode(c);
}
}
gps.f_get_position(&flat, &flon, &age);
velocity = round(gps.f_speed_kmph());
char buf[16];
getStr = dtostrf(flat, 4, 6, buf);
getStr += “~”;
getStr += dtostrf(flon, 4, 6, buf);
getStr += “~”;
getStr += dtostrf(velocity, 3, 1, buf);
ss.end();
return getStr;
}
String aesEncryptedData(String dataString) {
AES aes;
byte key = (unsigned char)“01234567890101230123456789010123”;
int bits = 256;
byte iv [N_BLOCK] ;
unsigned long long int myIv = 123456789;
byte plain[dataString.length()];
int plainLength = sizeof(plain) - 1;
dataString.getBytes(plain, plainLength);
int padedLength = plainLength + N_BLOCK - plainLength % N_BLOCK;
byte plain_p[padedLength];
byte cipher [padedLength] ;
byte check [padedLength] ;
aes.set_IV(myIv);
aes.get_IV(iv);
aes.do_aes_encrypt(plain, plainLength, cipher, key, bits, iv);
aes.set_IV(myIv);
aes.get_IV(iv);
char ivdata[sizeof(iv)];
int encrypted_size = sizeof(cipher);
char encoded[encrypted_size];
base64_encode(encoded, (char*)cipher, encrypted_size);
base64_encode(ivdata, (char*)iv, sizeof(iv));
String d = (char*) encoded;
String d1 = (char*) ivdata;
String d2 = d1 + “~” + d;
return (urlencode(d2));
}
void sendData(String data) {
int delayTime = 1000;
int delayTimeF = 250;
SIM900.begin(9600);
SIM900.println("AT"); /* Check Communication */
delay(delayTime);
SIM900.println("AT+CIPMODE=0"); /* Non-Transparent (normal) mode for TCP/IP application */
delay(delayTime);
SIM900.println("AT+CIPMUX=0"); /* Single TCP/IP connection mode */
delay(delayTime);
SIM900.println("AT+CGATT=1"); /* Attach to GPRS Service */
delay(delayTime);
SIM900.println("AT+CREG?"); /* Network registration status */
delay(delayTime);
SIM900.println("AT+CGATT?"); /* Attached to or detached from GPRS service */
delay(delayTime);
SIM900.println("AT+CSTT=\"internet\""); /* Start task and set APN */
delay(delayTime);
SIM900.println("AT+CIICR"); /* Bring up wireless connection with GPRS */
delay(delayTime);
SIM900.println("AT+CIFSR"); /* Get local IP address */
delay(delayTime);
SIM900.println("AT+CIPSTART=\"TCP\",\"****.************.in\",80");
delay(2000);
SIM900.println("AT+CIPSEND"); /* Send data through TCP connection */
delay(delayTime);
SIM900.println(data); /* URL for data to be sent to */
delay(delayTime);
SIM900.println("AT+CIPSHUT"); /* Deactivate GPRS PDP content */
delay(delayTime);
SIM900.end();
}
String urlencode(String str)
{
String encodedString = “”;
char c;
char code0;
char code1;
char code2;
for (int i = 0; i < str.length(); i++) {
c = str.charAt(i);
if (c == ’ ') {
encodedString += ‘+’;
} else if (isalnum©) {
encodedString += c;
} else {
code1 = (c & 0xf) + ‘0’;
if ((c & 0xf) > 9) {
code1 = (c & 0xf) - 10 + ‘A’;
}
c = (c >> 4) & 0xf;
code0 = c + ‘0’;
if (c > 9) {
code0 = c - 10 + ‘A’;
}
code2 = ‘\0’;
encodedString += ‘%’;
encodedString += code0;
encodedString += code1;
//encodedString+=code2;
}
yield();
}
return encodedString;
}
Thank You.
Best Regards.
Richards Babu.