Arduino Uno R3 + SIM900

hello,
i'm programmer trying hardware

i'm trying connect sim900 shield bought online. i've followed plenty of tutorials out there connect sim shield arduino uno.

well, it's not going well.

i've put unlocked sim in it, , netlight led blinks 3 in 3 seconds meaning found network.

i have set pins d7 , d8, plenty of people indicate. using power supply of 9v 1a.

but when try run simple basic example codes, don't execute normally.

i run example code:

code: [select]

#include <softwareserial.h>

softwareserial gprs(7, 8);

unsigned char buffer[64];  // buffer array data receive on serial port
int count=0;               // counter buffer array

void setup()
{
  gprs.begin(19200);
  serial.begin(19200);
}

void loop()
{
  if (gprs.available())
  {
    while(gprs.available())
    {
      buffer[count++]=gprs.read();
      if(count == 64)break;
    }
    serial.write(buffer,count);
    clearbufferarray();
    count = 0;
  }
  if (serial.available())
    gprs.write(serial.read());
}

void clearbufferarray()
{
  (int i=0; i<count;i++)
  {
    buffer[i]=null;
  }
}

after type at
and in serial monitor 19200 baud selected , prints


(two ??)

seems commands aren't being sent ...

here how have stuff built

found solution


opened
my gsm library (in libraries folder), openeced gsm.cpp , changed pin values (the tx , rx pins)

Arduino Forum > Using Arduino > Programming Questions > Arduino Uno R3 + SIM900

arduino