Making voice calls With Arduino + GSM Shield
Making voice calls
Through the modem, it is possible to make voice calls. In order to
speak to and hear the other party, you will need to add a speaker and
microphone.
On the underside of the shield, there are through-holes labeled M1P and M1N. These are the positive and negative voice input pins for a microphone. The through-holes labeled S1P and S1N are the positive and negative voice output pins, to which you need to connect a speaker.
On page 43 of the modem documentation, there is an example voice and sound circuit that will connect to an earphone:
The following sketch allows you to place a
voice call. Using the serial monitor, you can enter the remote phone
number and terminate the call. When you see the READY message, type a
phone number. Make sure the serial monitor is set to send a just newline
when you press return.
#include <GSM.h>
// PIN Number
#define PINNUMBER ""
// initialize the library instance
GSM gsmAccess; // include a 'true' parameter for debug enabled
GSMVoiceCall vcs;
String remoteNumber = ""; // the number you will call
char charbuffer[20];
void setup()
{
// initialize serial communications
Serial.begin(9600);
Serial.println("Make Voice Call");
// 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("Enter phone number to call.");
}
void loop()
{
// add any incoming characters to the String:
while (Serial.available() > 0)
{
char inChar = Serial.read();
// if it's a newline, that means you should make the call:
if (inChar == '\n')
{
// make sure the phone number is not too long:
if (remoteNumber.length() < 20)
{
// show the number you're calling:
Serial.print("Calling to : ");
Serial.println(remoteNumber);
Serial.println();
// Call the remote number
remoteNumber.toCharArray(charbuffer, 20);
// Check if the receiving end has picked up the call
if(vcs.voiceCall(charbuffer))
{
Serial.println("Call Established. Enter line to end");
// Wait for some input from the line
while(Serial.read()!='\n' && (vcs.getvoiceCallStatus()==TALKING));
// And hang up
vcs.hangCall();
}
Serial.println("Call Finished");
remoteNumber="";
Serial.println("Enter phone number to call.");
}
else
{
Serial.println("That's too long for a phone number. I'm forgetting it");
remoteNumber = "";
}
}
else
{
// add the latest character to the message to send:
if(inChar!='\r')
remoteNumber += inChar;
}
}
}
// PIN Number
#define PINNUMBER ""
// initialize the library instance
GSM gsmAccess; // include a 'true' parameter for debug enabled
GSMVoiceCall vcs;
String remoteNumber = ""; // the number you will call
char charbuffer[20];
void setup()
{
// initialize serial communications
Serial.begin(9600);
Serial.println("Make Voice Call");
// 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("Enter phone number to call.");
}
void loop()
{
// add any incoming characters to the String:
while (Serial.available() > 0)
{
char inChar = Serial.read();
// if it's a newline, that means you should make the call:
if (inChar == '\n')
{
// make sure the phone number is not too long:
if (remoteNumber.length() < 20)
{
// show the number you're calling:
Serial.print("Calling to : ");
Serial.println(remoteNumber);
Serial.println();
// Call the remote number
remoteNumber.toCharArray(charbuffer, 20);
// Check if the receiving end has picked up the call
if(vcs.voiceCall(charbuffer))
{
Serial.println("Call Established. Enter line to end");
// Wait for some input from the line
while(Serial.read()!='\n' && (vcs.getvoiceCallStatus()==TALKING));
// And hang up
vcs.hangCall();
}
Serial.println("Call Finished");
remoteNumber="";
Serial.println("Enter phone number to call.");
}
else
{
Serial.println("That's too long for a phone number. I'm forgetting it");
remoteNumber = "";
}
}
else
{
// add the latest character to the message to send:
if(inChar!='\r')
remoteNumber += inChar;
}
}
}