Changed how SMS receiving is handled

checkForSms will return index of received sms

Author: sekyHC

Sim800L.cpp

@@ -493,6 +493,30 @@ bool Sim800L::sendSms(char* number,char* text)
 }
 
 
+void Sim800L::prepareForSmsReceive()
+{
+	// Configure SMS in text mode
+	this->SoftwareSerial::print (F("AT+CMGF=1\r"));
+	this->SoftwareSerial::print(F("AT+CNMI=2,1,0,0,0\r"));
+}
+
+const uint8_t Sim800L::checkForSMS()
+{
+	 _buffer = _readSerial(100);
+	 if(_buffer.length() == 0)
+	 {
+	 	return 0;
+	 }
+	 //Serial.println(_buffer);
+	 // +CMTI: "SM",1
+	 if(_buffer.indexOf("CMTI") == -1)
+	 {
+	 	return 0;
+	 }
+	 return _buffer.substring(_buffer.indexOf(',')+1).toInt();
+}
+
+
 String Sim800L::getNumberSms(uint8_t index)
 {
     _buffer=readSms(index);
@@ -513,25 +537,28 @@ String Sim800L::getNumberSms(uint8_t index)
 
 String Sim800L::readSms(uint8_t index)
 {
-
     // Can take up to 5 seconds
 
-    this->SoftwareSerial::print (F("AT+CMGF=1\r"));
+    if (( _readSerial(5000).indexOf("ER")) != -1)
+    {
+    	return "";
+    }
 
-    if (( _readSerial(5000).indexOf("ER")) ==-1)
+    this->SoftwareSerial::print (F("AT+CMGR="));
+    this->SoftwareSerial::print (index);
+    this->SoftwareSerial::print ("\r");
+    _buffer=_readSerial();
+    //Serial.println(_buffer);
+    if (_buffer.indexOf("CMGR") == -1)
     {
-        this->SoftwareSerial::print (F("AT+CMGR="));
-        this->SoftwareSerial::print (index);
-        this->SoftwareSerial::print ("\r");
-        _buffer=_readSerial();
-        if (_buffer.indexOf("CMGR:")!=-1)
-        {
-            return _buffer;
-        }
-        else return "";
+    	return "";
     }
-    else
-        return "";
+
+	_buffer=_readSerial();
+	//Serial.println(_buffer);
+	byte first = _buffer.indexOf('\n', 2) + 1;
+	byte second = _buffer.indexOf('\n', first);
+    return _buffer.substring(first, second);
 }
 
 

Sim800L.h

@@ -74,7 +74,6 @@
 #define DEFAULT_BAUD_RATE		9600
 #define TIME_OUT_READ_SERIAL	5000
 
-
 class Sim800L : public SoftwareSerial
 {
 private:
@@ -91,7 +90,6 @@ class Sim800L : public SoftwareSerial
     String _readSerial();
     String _readSerial(uint32_t timeout);
 
-
 public:
 
     uint8_t	RX_PIN;
@@ -130,6 +128,8 @@ class Sim800L : public SoftwareSerial
     bool hangoffCall();
     uint8_t getCallStatus();
 
+	const uint8_t checkForSMS();
+	void prepareForSmsReceive();
     bool sendSms(char* number,char* text);
     String readSms(uint8_t index);
     String getNumberSms(uint8_t index);

examples/readSms/readSms.ino

@@ -71,20 +71,25 @@ Sim800L GSM(RX, TX);
  * Sim800L GSM(RX, TX, RESET);        
  * Sim800L GSM(RX, TX, RESET, LED);
  */
-
-String text;     				// to save the text of the sms
-uint8_t index;   				// to indicate the message to read.
-
+ 
+/*
+ * NOTICE:
+ * FOR THIS TO WORK YOU HAVE TO INCREASE RX BUFFER SIZE
+ * Open SoftwareSerial.h and change _SS_MAX_RX_BUFF to 256
+ *
+ */
 
 void setup() {
-  Serial.begin(9600); 
-  GSM.begin(4800); 
-  index = 1; 
-  text = GSM.readSms(index);
-  Serial.println(text);
-
+  Serial.begin(9600);
+  GSM.begin(4800);
+  GSM.delAllSms(); // this is optional
+  GSM.prepareForSmsReceive();
 }
 
 void loop() {
-  //do nothing
-}
+  byte index = GSM.checkForSMS();
+  if(index != 0)
+  {
+  	Serial.println(gsm.readSms(index));
+  }
+}