Hi All,
I am currently trying to use an Arduino UNO with a sim808 gsm module and running a sample code from a sim900 library (which I read is compatible with minor adjustments, of which I adjusted). The issue I am having is when I receive an sms it will print on the Serial monitor a smsposition = -2, and then a sms position of 1 and then print the value of the sms_text which I had sent.
This happens occasionally yet at times the program works fine, and at times it'll pull sms which had been sent 30 mins ago. below are the code and a snippet of the serial monitor (the redacted portion is the sender's phone number)
#include "SIM900.h"
#include <SoftwareSerial.h>
//If not used, is better to exclude the HTTP library,
//for RAM saving.
//If your sketch reboots itself proprably you have finished,
//your memory available.
//#include "inetGSM.h"
//If you want to use the Arduino functions to manage SMS, uncomment the lines below.
#include "sms.h"
SMSGSM sms;
//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 send and receive SMS.
int numdata;
boolean started=false;
char smsbuffer[160];
char n[20];
//debug begin
char sms_position;
char phone_number[20]; // array for the phone number string
char sms_text[100];
int i;
//debug end
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(4800))
{
Serial.println("\nstatus=READY");
started=true;
}
else
Serial.println("\nstatus=IDLE");
if(started)
{
//Enable this two lines if you want to send an SMS.
//if (sms.SendSMS("3471234567", "Arduino SMS"))
//Serial.println("\nSMS sent OK");
//if NO SPACE ,you need delte SMS from position 1 to position 20
//please enable this four lines
for(i=1;i<=20;i++)
{
sms.DeleteSMS(i);
}
}
};
void loop()
{
if(started)
{
//Read if there are messages on SIM card and print them.
sms_position=sms.IsSMSPresent(SMS_UNREAD);
if (sms_position)
{
// read new SMS
Serial.print("SMS postion:");
Serial.println(sms_position,DEC);
sms.GetSMS(sms_position, phone_number, sms_text, 100);
// now we have phone number string in phone_num
Serial.println(phone_number);
// and SMS text in sms_text
Serial.println(sms_text);
}
else
{
Serial.println("NO NEW SMS,WAITTING");
}
delay(1000);
}
};
GSM Shield testing.
status=READY
SMS postion:1
Hi
SMS postion:2
Hello
SMS postion:3
200
SMS postion:-2
200
SMS postion:4
Shop
The above section was copied and pasted from the Serialmoniter, the issue is that sms position 3 should have printed "search" not "200" and position 4 should have contained "100", not shop. Shop was sent 10 messages ago.
