A few days ago I received the SIM900 Quad-band GSM/GPRS Shield for Arduino. I want to send data from a temperature sensor to a MySQL data base but I can not comunicate the arduino uno with the shield.
I tested the shield following the steps from this link SimPasture.com is for sale | HugeDomains but when I type the letters AT in the serial monitor, I receive nothing.
what is wrong?
thanks in advance.
Same shield or a different one?
the shield is this: http://www.ebay.com/itm/SIM900-Quad-band-GSM-GPRS-Shield-for-Arduino-/221176159800
Yes, I know that one, the TinyOS one. You have changed the pins that SoftwareSerial uses haven't you?
no I haven´t.
what Softwareserial pins uses this shield?
Set the jumpers to SW, and use
SoftwareSerial GPRS(2, 3);
D8 is the software power pin.
I set the pins but I still receive nothing in the serial monitor.
this is the code:
//Serial Relay - Arduino will patch a
//serial link between the computer and the GPRS Shield
//at 19200 bps 8-N-1
//Computer is connected to Hardware UART
//GPRS Shield is connected to the Software UART
#include <SoftwareSerial.h>
SoftwareSerial GPRS(2, 3);
unsigned char buffer[64]; // buffer array for data receive over serial port
int count=0; // counter for 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()
{
for (int i=0; i<count;i++)
{
buffer[i]=NULL;
}
}
Now, I type "AT" in the serial monitor and I receive "AT" but "OK" doesnt appear.
Obvious question - you have turned it on?
Try dropping the Serial speed to 9600?
hi again.
I tried all what you said but nothing happens and then I tried this code and it works.
#include "SIM900.h"
#include <SoftwareSerial.h>
#include "inetGSM.h"
//#include "sms.h"
//#include "call.h"
//To change pins for Software Serial, use the two lines in GSM.cpp.
//GSM Shield for Arduino
//www.open-electronics.org
//this code is based on the example of Arduino Labs.
//Simple sketch to start a connection as client.
InetGSM inet;
//CallGSM call;
//SMSGSM sms;
char msg[50];
int numdata;
char inSerial[50];
int i=0;
boolean started=false;
void setup()
{
//Serial connection.
Serial.begin(9600);
Serial.println("GSM Shield testing.");
//Start configuration of shield with baudrate.
//For http uses is raccomanded to use 4800 or slower.
if (gsm.begin(2400)) {
Serial.println("\nstatus=READY");
started=true;
} else Serial.println("\nstatus=IDLE");
if(started) {
//GPRS attach, put in order APN, username and password.
//If no needed auth let them blank.
if (inet.attachGPRS("internet.wind", "", ""))
Serial.println("status=ATTACHED");
else Serial.println("status=ERROR");
delay(1000);
//Read IP address.
gsm.SimpleWriteln("AT+CIFSR");
delay(5000);
//Read until serial buffer is empty.
gsm.WhileSimpleRead();
//TCP Client GET, send a GET request to the server and
//save the reply.
numdata=inet.httpGET("www.google.com", 80, "/", msg, 50);
//Print the results.
Serial.println("\nNumber of data received:");
Serial.println(numdata);
Serial.println("\nData received:");
Serial.println(msg);
}
};
void loop()
{
//Read for new byte on serial hardware,
//and write them on NewSoftSerial.
serialhwread();
//Read for new byte on NewSoftSerial.
serialswread();
};
void serialhwread()
{
i=0;
if (Serial.available() > 0) {
while (Serial.available() > 0) {
inSerial[i]=(Serial.read());
delay(10);
i++;
}
inSerial[i]='\0';
if(!strcmp(inSerial,"/END")) {
Serial.println("_");
inSerial[0]=0x1a;
inSerial[1]='\0';
gsm.SimpleWriteln(inSerial);
}
//Send a saved AT command using serial port.
if(!strcmp(inSerial,"TEST")) {
Serial.println("SIGNAL QUALITY");
gsm.SimpleWriteln("AT+CSQ");
}
//Read last message saved.
if(!strcmp(inSerial,"MSG")) {
Serial.println(msg);
} else {
Serial.println(inSerial);
gsm.SimpleWriteln(inSerial);
}
inSerial[0]='\0';
}
}
void serialswread()
{
gsm.SimpleRead();
}
I modified the code to insert temperature data from a sensor to a MySQL data base but when it execute
inet.httpGET("hostname", 80, "/insert_data.php?Temperature=22.4&Ph=5.5", msg, 50);
the green led of the shield turns off and doesn't upload the data. I use a USB from de pc to supply power to the arduino.
maybe is not enough power?
All the GPRS shields I have come across can draw up to 2 amps when transmitting. If the voltage drops below a certain level then the SIM900 will automatically shut down.
I strongly suspect you aren't providing enough power.
what do you recommend? DC 9V/1A Power Supply? DC 12V/86mA Power Supply? I am afraid to fry up the arduino
If that's the selection you have available then the 9 volt supply. Personally I use 5 volt, 2 amp supplies.
Thanks for your help.
I was looking for a 5v 2amp power supply and I found it but the problem continues. I will try the 9v 1amp power supply and then I tell you.