Adding 1602 display to Gsm SHield+Arduino Uno rev3

Hi to all,

currently i have arduino uno with gsm shield working perfectly. I integrated a button (using pin 6 for buttonpin) and when the button is pressed (HIGH) i am making a voice call.

The skech

#include <GSM.h>

#define PINNUMBER ""

// initialize the library instance
GSM gsmAccess; // include a 'true' parameter for debug enabled
GSMVoiceCall vcs;
const int buttonPin = 6;     // the number of the pushbutton pin
const int ledPin =  13;      // the number of the LED pin
int buttonState = 0;         // variable for reading the pushbutton status

void setup()
  // initialize the LED pin as an output:
  pinMode(ledPin, OUTPUT);     
  // initialize the pushbutton pin as an input:
  pinMode(buttonPin, INPUT);     
  // initialize serial communications
 // Serial.println("SMS Messages Sender");

  // connection state
  boolean notConnected = true;

  // Start GSM shield
  // If your SIM has PIN, pass it as a parameter of begin() in quotes
      notConnected = false;
      Serial.println("Not connected");
 // Turn 13 pin led - READY ON
     digitalWrite(ledPin, HIGH);

 // Serial.println("GSM initialized");

void loop()
   buttonState = digitalRead(buttonPin);
if (buttonState == HIGH) {   
    // turn LED on:   

          // Turn Free LED OFF]    
          digitalWrite(ledPin, LOW);

          //Serial.println("Call Established. Enter line to end");
          // Wait for some input from the line
          // And hang up
        // TURN FREE LED ON AGAIN after call finished
                  digitalWrite(ledPin, HIGH);

       // Serial.println("Call Finished");

My question is can i use LCD display and connect (wire) the pins as shown Here , but to connect directly on top of the GSM shield not at the arduino as shown in the picture.

As i see now i am using pins 3,6,5V and GND and in this picture - to connect LCD we have noting to do with pins 3 and 6 , so can i be sure that there will not be a problem??..short circuit , using same pin…or something like that?


You cannot use pin 3. Pin 3 is used by GSM shield to receive information from Arduino board.

Thanks for the answer . then if i use another pin instead of pin 3 for the 1602 LCD screen, will everything work correctly?

LCD 1602 is using pins 2,3,4,5,11,12 , but if i change pin3 to with one of the pins (7,8,9,10) will this work? At the moment i think pins 7,8,9,10 are free i am not using them but not sure if GSM shield is not...?

Any other help? Is it only this - not to use pin 3 by the 1602 LCD screen? Nothing else to take care of? What about pins 2 and 7 ? as i see the also play role with the gsm shield?

pin 2 & 3 used by modem rx/tx pin 7 used for power modem you can use all other pins. I used the Analog A0-A5 pins to connect 1602 on modem shield. Works fine.

Did you add micro and Loudspeaker? How ???