Interface GSM Module to Arduino. In this article, we are going to see how to interface GSM Module to Arduino. There are different kinds of GSM modules available in market. We are using the most popular module based on Simcom SIM9. Arduino Uno for this tutorial.

Interfacing a GSM module to Arduino is pretty simple. You only need to make 3 connections between the gsm module and arduino. So lets get to business! A GSM Module is basically a GSM Modem  (like SIM 9.

We’ve seen a ton of people using these with AT commands and an external microcontroller but. The Joint Test Action Group (JTAG) is an electronics industry association formed in 1985 for developing a method of verifying designs and testing printed circuit. With Atmel's broad range of feature-rich 8-bit microcontrollers based on the 8051 instruction set, you can be assured that your 8051 designs are in good hands. INTRODUCTION: With this board you can develop and prototype with any of 8051 40 pin microcontrollers. The RS232 driver on board allows easy connection with PC or.

PCB with different types of output taken from the board – say TTL Output (for Arduino, 8. RS2. 32 Output to interface directly with a PC (personal computer). Setup Gr Setup Gradle more. The board will also have pins or provisions to attach mic and speaker, to take out +5.

V or other values of power and ground connections. These type of provisions vary with different modules. Lots of varieties of GSM modem and GSM Modules are available in the market to choose from. For our project of connecting a gsm modem or module to arduino and hence send and receive sms using arduino – its always good to choose an arduino compatible GSM Module – that is a GSM module with TTL Output provisions. GSM Module – Buyers Guide – are you looking to buy a GSM module? There are a handful of product variants for GSM module – like SIM9.

SIM3. 00, SIM8. 00 etc. We have created this buyers guide to help you select the right GSM module for your project needs. Notes on GSM Module. We use SIM9. 00 GSM Module – This means the module supports communication in 9.

MHz band. We are from India and most of the mobile network providers in this country operate in the 9. Mhz band. If you are from another country, you have to check the mobile network band in your area. A majority of United States mobile networks operate in 8.

Mhz band (the band is either 8. Mhz or 1. 90. 0Mhz). Canada operates primarily on 1. Mhz band. Please read this wiki entry on GSM Frequency Bands around the World. Check the power requirements of GSM module – GSM modules are manufactured by different companies. They all have different input power supply specs. You need to double check your GSM modules power requirements.

For exaple if you read location 0003 you will get 99 (see image above). Note each cell can store 8BITs of data so range you can store is 0-255 (-128 to +127).

In this tutorial, our gsm module requires a 1. So we feed it using a 1. V,1. A DC power supply.

I have seen gsm modules which require 1. They differ with manufacturers. If you are having a 5.

V module, you can power it directly from Arduino’s 5. V out. Note: - GSM Modules are manufactured by connecting a particular GSM modem to a PCB and then giving provisions for RS2. TTL outputs, Mic and Speaker interfacing provisions etc. The most popular modem under use is SIM 9. SIMCom. They also manufacture GSM Modems in bands 8. Check for TTL Output Pins in the module – You can feed the data from gsm module directly to Arduino only if the module is enabled with TTL output pins.

Otherwise you have to convert the RS2. TTL using MAX2. 32 IC and feed it to Arduino. Most of the gsm modules in market are equipped with TTL output pins. Just ensure you are buying the right one. So that’s all about the gsm module basics. Now lets power it up!

Booting the GSM Module! Insert the SIM card to GSM module and lock it. Connect the adapter to GSM module and turn it ON! Now wait for some time (say 1 minute) and see the blinking rate of . Once the connection is established successfully, the status/network LED will blink continuously every 3 seconds.

You may try making a call to the mobile number of the sim card inside GSM module. If you hear a ring back, the gsm module has successfully established network connection. Okay! Now let’s see how to connect a gsm module to Arduino! Connecting GSM Module to Arduino. There are two ways of connecting GSM module to arduino. In any case, the communication between Arduino and GSM module is serial. So we are supposed to use serial pins of Arduino (Rx and Tx).

So if you are going with this method, you may connect the Tx pin of GSM module to Rx pin of Arduino and Rx pin of GSM module to Tx pin of Arduino. You read it right ? GSM Tx –> Arduino Rx and GSM Rx –> Arduino Tx. Now connect the ground pin of arduino to ground pin of gsm module! So that’s all! You made 3 connections and the wiring is over!

Now you can load different programs to communicate with gsm module and make it work. Note: - The problem with this connection is that, while programming Arduino uses serial ports to load program from the Arduino IDE. If these pins are used in wiring,  the program will not be loaded successfully to Arduino. So you have to disconnect wiring in Rx and Tx each time you burn the program to arduino.

Once the program is loaded successfully, you can reconnect these pins and have the system working! To avoid this difficulty, I am using an alternate method in which two digital pins of arduino are used for serial communication.

We need to select two PWM enabled pins of arduino for this method. So I choose pins 9 and 1. PWM enabled pins). This method is made possible with the Software. Serial Library of Ardunio. Software. Serial is a library of Arduino which enables serial data communication through other digital pins of Arduino.

The library replicates hardware functions and handles the task of serial communication. I hope you understood so far! So given below is the circuit diagram to connect gsm module to arduino – and hence use the circuit to send sms and receive sms using arduino and gsm modem.

Make the connections as shown! Now lets get to the coding part. The program has two objectives as described below: -1) Send SMS using Arduino and GSM Module – to a specified mobile number inside the program. Receive SMS using Arduino and GSM Module – to the SIM card loaded in the GSM Module. The Program #include < Software. Serial. h>. Software.

Serial my. Serial(9, 1. Let’s get to explanation of program! The Program Explanation. We begin by including Software. Serial library into the program.

The actual format is like Software. Serial my. Serial (Rx, Tx); So in our code, pin number 9 will act as Rx of Arduino and 1. Tx of Arduino. The first task is to set baud rates of Software. Serial library to communicate with GSM module. We achieve this by invoking my. Serial. begin function. Our second task is to set the baud rate of Arduino IDE’s Serial Monitor.

We do this by invoking Serial. Both should be set at the same baud rate and we use 9. To make things simpler, I have developed a user input based program.

The program seeks user input via serial monitor of Arduino. If the input is . If the user input is . The whole program is as simple as that! Serial. available() – checks for any data coming through serial port of arduino. The function returns the number of bytes available to read from serial buffer. If there is no data available, it returns a - 1 (value less than zero).

Serial. read() – Reads all the data available on serial buffer (or incoming serial data if put otherwise). Returns the first byte of incoming serial data. Serial. available() – checks for any data coming from GSM module through the Software. Serial pins 9 and 1. Returns the number of bytes available to read from software serial port.

Returns a - 1 if no data is available to read. Serial. read() – Reads the incoming data through software serial port. Serial. write() – Prints data to serial monitor of arduino. So the function Serial. Serial. read()) – prints the data collected from software serial port to serial monitor of arduino. Lets get the functions Send. Message()  and Recieve.

Message()These are the functions in which we actually send commands to GSM module from Arduino. These commands to communicate with GSM module are called AT Commands. There are different commands to perform different tasks using the GSM module. You can read complete AT Commands Library to understand all that is possible with GSM module. Send. Message() – is the function we created in our arduino sketch to send an SMS. To send an SMS, we should set our GSM module to Text mode first.

This is achieved by sending an AT Command “AT+CMGF=1”  We send this command by writing this to Software. Serial port. To achieve this we use the my.

Serial. println() function.