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GSM : GSM_SMS class

peek()

Description

Returns the next byte (character) of an incoming SMS without removing it from the message. That is, successive calls to peek() will return the same character, as will the next call to read(). peek() inherits from the Stream utility class.

Syntax

SMS.peek()

Parameters

none

Returns

int - the first byte available of a SMS message (or -1 if no data is available)

Example

/*
SMS receiver

 This sketch, for the Arduino GSM shield, waits for SMS messages
 and displays them through the Serial port.

 Circuit:
 * GSM shield

 created 25 Feb 2012
 by Javier Zorzano / TD

 This example is in the public domain.
*/

// libraries
#include <GSM.h>

// PIN Number
#define PINNUMBER ""

// initialize the library instance
GSM gsmAccess; // include a 'true' parameter for debug enabled
GSM_SMS sms;

char remoteNumber[20];  // Holds the emitting number

void setup()
{
  // initialize serial communications
  Serial.begin(9600);

  Serial.println("SMS Messages Receiver");

  // connection state
  boolean notConnected = true;

  // Start GSM shield
  // If your SIM has PIN, pass it as a parameter of begin() in quotes
  while(notConnected)
  {
    if(gsmAccess.begin(PINNUMBER)==GSM_READY)
      notConnected = false;
    else
    {
      Serial.println("Not connected");
      delay(1000);
    }
  }

  Serial.println("GSM initialized");
  Serial.println("Waiting for messages");
}

void loop()
{
  char c;

  // If there are any SMSs available()  
  if (sms.available())
  {
    Serial.println("Message received from:");

    // Get remote number
    sms.remoteNumber(remoteNumber, 20);
    Serial.println(remoteNumber);

    // This is just an example of message disposal    
    // Messages starting with # should be discarded
    if(sms.peek()=='#')
    {
      Serial.println("Discarded SMS");
      sms.flush();
    }

    // Read message bytes and print them
    while(c=sms.read())
      Serial.print(c);

    Serial.println("\nEND OF MESSAGE");

    // delete message from modem memory
    sms.flush();
    Serial.println("MESSAGE DELETED");
  }

  delay(1000);

}

 
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See Also

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The text of the Arduino reference is licensed under a Creative Commons Attribution-ShareAlike 3.0 License. Code samples in the reference are released into the public domain.