Call and Message using Arduino and GSM Module

Make/answer call and Read/send SMS using Arduino

Sometimes people find it difficult to use the GSM Module for its basic functions like calling, texting etc., specifically with the Microcontrollers. So here we are going to build a Simple Mobile Phone using Arduino, in which GSM Module is used to Make the Call, answer the Call, send SMS, and read SMS, and also this Arduino phone has Mic and Speaker to talk over this Phone. This project will also serve as a proper interfacing of GSM Module with Arduino, with all the Code needed to operate any Phone’s basic functions.

Components Required:

·         Arduino Uno

·         GSM Module SIM900

·         16x2 LCD

·         4x4 Keypad

·         Breadboard or PCB

·         Connecting jumper wire

·         Power supply

·         Speaker

·         MIC

·         SIM Card

Working Explanation:

In this Arduino Mobile Phone Project, we have used Arduino Uno to control whole system’s features and interfacing all the components in this system. A 4x4 Alphanumeric Keypad is used for taking all kind of inputs like: Enter mobile number, type messages, make a call, receive a call, send SMS, read SMS etc. GSM Module is used to communicate with the network for calling and messaging purpose. We have also interfaced a MIC and a Speaker for Voice Call and Ring sound and a 16x2 LCD is used for showing messages, instructions and alerts.

Alphanumeric is a method to enter numbers and alphabets both by using same keypad. In this method, we have interfaced 4x4 keypad with Arduino and written Code for accepting alphabets too, check the Code in Code section below.

Working of this project is easy. All the features will be performed by Using Alphanumeric Keypad. Check the Full code and a Demo Video below to properly understand the process. Here we are going to explain all the four features of the projects below.

Explaining Four Features of Arduino Mobile Phone:

1. Make a Call:

To make a call by using our Arduino based Phone, we have to press ‘C’ and then need to enter the Mobile Number on which we want to make a call. Number will be entered by using alphanumeric keypad. After entering the number we again need to press ‘C’. Now Arduino will process for connecting the call to the entered number by using AT command:

ATDxxxxxxxxxx; <Enter>     where xxxxxxxxx is entered Mobile Number.

2. Receive a Call:

Receiving a call is very easy. When someone is calling to your system SIM number, which is there in GSM Module, then your system will show ‘Incoming…’ message over the LCD with incoming number of caller. Now we just need to Press ‘A’ to attend this call. When we press ‘A’, Arduino will send given command to GSM Module:

ATA <enter>

3. Send SMS:

When we want to send a SMS using our Arduino based Mobile Phone, then we need to Press ‘B’. Now System will ask for Recipient Number, means ‘to whom’ we want to send SMS. After entering the number we need to press ‘D’ and now LCD asks for message. Now we need to type the message, like we enter in normal mobile, by using keypad and then after entering the message we need to press ‘D’ to send SMS.  To Send SMS Arduino sends given command:

AT+CMGF=1 <enter>

AT+CMGS=”xxxxxxxxxx” <enter>     where: xxxxxxxxxx is entered mobile number

And send 26 to GSM to send SMS.  

4. Receive and Read SMS:

This feature is also simple. In this, GSM will receive SMS and stores it in SIM card. And Arduino continuously monitors the received SMS indication over UART. We just need to Press ‘D’, to read the SMS, when we see the New Message symbol (like a envelope: See the Video at the end) on the LCD. Below is the SMS Received indication displayed on the Serial port is:

+CMTI: “SM” <SMS stored location>       

+CMTI: “SM”,6  Where 6 is message location where it stored in SIM card.

When Arduino gets this ‘SMS received’ indication then it extracts SMS storing location and sends command to GSM to read the received SMS. And show a ‘New Message Symbol’ over the LCD.

AT+CMGR=<SMS stored location><enter>

AT+CMGR=6

Now GSM sends stored message to Arduino and then Arduino extract main SMS and display it over the LCD and then after reading this SMS Arduino Clear the ‘New SMS symbol’ from the LCD.

Note: There is no coding for MIC and Speaker.

Check the Full code and a Demo Video below to properly understand the process.

Circuit Diagram and Explanation:

Circuit Diagram of this for interfacing GSM SIM900 and Arduino is given above. 16x2 LCD pins RS, EN, D4, D5, D6 and D7 are connected with pin number 14, 15, 16, 17, 18 and 19 of Arduino respectively. GSM Module’s Rx and Tx pins are directly connected with Arduino’s pin D3 and D2 respectively (Ground of Arduino and GSM must be connected with each other). 4x4 keypad Row pins R1, R2, R3, R4 are directly linked to pin number 11,10, 9, 8 of Arduino and Colum pins of keypad C1, C2, C3 are linked with pin number 7, 6, 5, 4 of Arduino. MIC is directly connected at mic+ and mic- of GSM Module and Speaker is directly connected at SP+ and SP- pins for GSM Module.

Programming Explanation:

Programming part of this project is little complex for beginners. In this code we have used keypad library #include <Keypad.h> for interfacing simple keypad for entering numbers. And for entering alphabets with the same keypad, we have created function void alfakey(). Means we have made every key multi functioning and we can enter any character or integer by using only 10 keys.

Like if we press key 2 (abc2), it will show ‘a’ and if we presses it again then it will replace ‘a’ to ‘b’ and if again we press three times then it will show ‘c’ at same place in LCD. If we wait for some time after pressing key, cursor will automatic move to next position in LCD. Now we can enter next char or number. The same procedure is applied for other keys.

#include <Keypad.h>

const byte ROWS = 4; //four rows

const byte COLS = 4; //four columns

char hexaKeys[ROWS][COLS] =

{

  {'1','2','3','A'},

  {'4','5','6','B'},

  {'7','8','9','C'},

  {'*','0','#','D'}

};

byte rowPins[ROWS] = {11, 10, 9, 8}; //connect to the row pinouts of the keypad

byte colPins[COLS] = {7, 6, 5, 4}; //connect to the column pinouts of the keypad

//initialize an instance of class NewKeypad

Keypad customKeypad = Keypad( makeKeymap(hexaKeys), rowPins, colPins, ROWS, COLS);

void alfakey()

{

 int x=0,y=0;

 int num=0;

  while(1)

  {

    lcd.cursor();

    char key=customKeypad.getKey();

    if(key)

    {

       if(key=='1')

       {

         num=0;

         lcd.setCursor(x,y);

         .... .....

         ........ ....

  Demo & Code

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