Posts with «gsm» label

Hackaday Prize Entry: USB GSM GPS 9DOF SD TinyTracker Has All the Acronyms

[Paul] has put together an insanely small yet powerful tracker for monitoring all the things. The USB TinyTracker is a device that packages a 48MHz processor, 2G modem, GPS receiver, 9DOF motion sensor, barometer, microphone, and micro-SD slot for data storage. He managed to get it all to fit into a USB thumb drive enclosure, meaning that you can program it however you want in the Arduino IDE, then plug it into any USB port and let it run. This enables things like remote monitoring, asset tracking, and all kinds of spy-like activity.

One of the most unusual aspects of his project, though, is this line: “Everything came together very nicely and the height of parts and PCBs is exactly as I planned.” [Paul] had picked out an enclosure that was only supposed to fit a single PCB, but with some careful calculations, and picky component selection, he managed to fit everything onto two 2-layer boards that snap together with a connector and fit inside the enclosure.

We’ve followed [Paul’s] progress on this project with an earlier iteration of his GSM GPS Tracker, which used a Teensy and fit snugly into a handlebar, but this one is much more versatile.


Filed under: The Hackaday Prize

Rotary Cell Phone: Blast from a Past that Never Was

The 1970s called and they want their rotary dial cell phone back.

Looking for all the world like something assembled from the Radio Shack parts department – remember when Radio Shack sold parts? – [Mr_Volt]’s build is a celebration of the look and feel of a hobbyist build from way back when. Looking a little like a homebrew DynaTAC 8000X, the brushed aluminum and 3D-printed ABS case sports an unusual front panel feature – a working rotary dial. Smaller than even the Trimline phone’s rotating finger stop dial and best operated with a stylus, the dial translates rotary action to DTMF tones for the Feather FONA board inside. Far from a one-trick pony, the phone sports memory dialing, SMS messaging, and even an FM receiver. But most impressive and mysterious is the dial mechanism, visible through a window in the wood-grain back. Did [Mr_Volt] fabricate those gears and the governor? We’d love to hear the backstory on that.

This isn’t the first rotary cell phone hybrid we’ve featured, of course. There was this GSM addition to an old rotary phone and this cell phone that lets you slam the receiver down. But for our money a rotary dial cell phone built from the ground up wins the retro cool prize of the bunch.

[via r/Arduino]


Filed under: Arduino Hacks, classic hacks

Hacking a rotary phone with an Arduino and a GSM shield

While cleaning out his closet, Instructables user “Acmecorporation”  discovered an old rotary telephone. Instead of tossing it away, the Maker decided to give the old-school device some modern-day technology using an Arduino Pro Mini and a SIM900 GSM shield.

Acmecorporation is able to use the aptly named TOWA Phone (There Once Was A Telephone) to make and receive calls, send single DMTF tones, and even program numbers on speed dial. Aside from its classic bell ringer, there’s an RGB LED that indicates GSM status: red for offline, green for online, and blue for an incoming call.

The Maker briefly explains how it works:

To make a phone call you have to pick up the handset and dial the number, that’s all. Terminate call hanging up the handset.

When phone is ringing, pick up the handset to answer. Terminate it hanging up.

If you call to a support center or an office, usually you have to dial numbers to connect a specific department. You can do this because TOWA sends single DMTF tones.

Inside the Arduino script, you can add your favorite telephone numbers and combine it with a specific integer number. For example, I’ve stored my favorites combined with numbers from 1 to 8. So when I pick up the handset and dial 1, it starts a call to my wife. When I dial 2 or 3, it calls one of my sons, and so on.

Although Acmecorporation didn’t design TOWA for everyday use, it has become a permanent fixture on his desk. Do you have a rotary phone lying around? Time to brush off the dust and rig your own!

APRS Tracking System Flies Your Balloons

Looking for a way to track your high-altitude balloons but don’t want to mess with sending data over a cellular network? [Zack Clobes] and the others at Project Traveler may have just the thing for you: a position-reporting board that uses the Automatic Packet Reporting System (APRS) network to report location data and easily fits on an Arduino in the form of a shield.

The project is based on an Atmel 328P and all it needs to report position data is a small antenna and a battery. For those unfamiliar with APRS, it uses amateur radio frequencies to send data packets instead of something like the GSM network. APRS is very robust, and devices that use it can send GPS information as well as text messages, emails, weather reports, radio telemetry data, and radio direction finding information in case GPS is not available.

If this location reporting ability isn’t enough for you, the project can function as a shield as well, which means that more data lines are available for other things like monitoring sensors and driving servos. All in a small, lightweight package that doesn’t rely on a cell network. All of the schematics and other information are available on the project site if you want to give this a shot, but if you DO need the cell network, this may be more your style. Be sure to check out the video after the break, too!


Filed under: radio hacks

Every word is like an unnecessary stain on silence

« Every word is like an unnecessary stain on silence and nothingness » is a sentence from Samuel Beckett but also the title of Eugenio Ampudia’s last artwork created and installed with the support of Ultra-lab  and running on Arduino Mega and GSM Shield:

The exhibition room has in its center a rectangular mirror made of water that reflects the room and the visitors. The perfect still water, metaphor of silence, is broken by the irruption of sporadic waves. These movements, the stain on silence, are provoked by the visitors’ interactions. In the heart of the water tank, a dispositive is able to receive calls and to open a valve. To each visitor’s call, so a series of movements is generated and break the calm.

Ultra-lab realized the technical part of the artwork thanks to an Arduino Mega, the Arduino GSM shield and various valves open and close by the Arduino Mega when a call is received by the shield. The dispositive is particularly interesting for its adaptation in a water context and for connecting valves.

Thanks to it, the artwork succeed to express beautifully the paradox between a destructive attraction for words and communication to which it’s hard to resist in order to prefer a finally inaccessible contemplation.

The work can be visited in the exhibition room Abierto X Obras in in the Spanish art center Matadero Madrid until the 17th of May 2015 and below you can watch a video interview with the artist:

Arduino Blog 09 Mar 20:01

GSM Controlled Star Light: A xmas tutorial for Intel Galileo

We recently posted on Intel Makers Community the first of a series of educational tutorial focused on Intel Galileo Gen 2. Our team worked on  a smart Christmas star able to receive sms and change pattern according to it. The bill of materials contains also an Arduino GSM Shield, a Proto Shield and some flexible  LED  strips:

To kick off a festive mood, we decided to adapt a typical Scandinavian tradition. In December, many people will decorate their homes by hanging large paper stars inside their windows. The stars usually have a single bulb inside that casts a warm, welcoming glow.

We thought we’d try to make this tradition a bit more merry by making it interactive. By sending text messages, we will change the blink pattern and color of the star.

This project is a fun and easy introduction on how to use the Intel Galileo Gen 2 board and the Arduino GSM shield. After making this tutorial, try modifying the code to change the patterns or taking the functions to insert GSM connectivity into your own projects.

Happy Holidays!

Follow the link and make it as well!

 

Arduino Blog 19 Dec 19:08

Over-engineering Ding Dong Ditch

One day, [Samy]’s best friend [Matt] mentioned he had a wireless doorbell. Astonishing. Even more amazing is the fact that anyone can buy a software defined radio for $20, a small radio module from eBay for $4, and a GSM breakout board for $40. Connect these pieces together, and you have a device that can ring [Matt]’s doorbell from anywhere on the planet. Yes, it’s the ultimate over-engineered ding dong ditch, and a great example of how far you can take practical jokes if you know which end of a soldering iron to pick up.

Simply knowing [Matt] has a wireless doorbell is not enough; [Samy] needed to know the frequency, the modulation scheme, and what the doorbell was sending. Some of this information can be found by looking up the FCC ID, but [Samy] found a better way. When [Matt] was out of his house, [Samy] simply rang the doorbell a bunch of times while looking at the waterfall plot with an RTL-SDR TV tuner. There are a few common frequencies tiny, cheap remote controls will commonly use – 315 MHz, 433 MHz, and 900 MHz. Eventually, [Samy] found the frequency the doorbell was transmitting at – 433.8 MHz.

After capturing the radio signal from the doorbell, [Samy] looked at the audio waveform in Audacity. It looked like this doorbell used On-Off Keying, or just turning the radio on for a binary ‘1’ and off for a binary ‘0’. In Audacity, everything the doorbell transmits becomes crystal clear, and with a $4 434 MHz transmitter from SparkFun, [Samy] can replicate the output of the doorbell.

For the rest of the build, [Samy] is using a mini GSM cellular breakout board from Adafruit. This module listens for any text message containing the word ‘doorbell’ and sends a signal to an Arduino. The Arduino then sends out the doorbell code with the transmitter. It’s evil, and extraordinarily over-engineered.

Right now, the ding dong ditch project is set up somewhere across the street from [Matt]’s house. The device reportedly works great, and hopefully hasn’t been abused too much. Video below.


Filed under: Arduino Hacks, radio hacks
Hack a Day 11 Dec 21:00

Arduino-Powered Alarm System Has All The Bells And Whistles

Put aside all of the projects that use an Arduino to blink a few LEDs or drive one servo motor. [IngGaro]‘s latest project uses the full range of features available in this versatile microcontroller and has turned an Arduino Mega into a fully-functional home alarm system.

The alarm can read RFID cards for activation and control of the device. It communicates with the front panel via an I2C bus, and it can control the opening and closing of windows or blinds. There is also an integrated GSM antenna for communicating any emergencies over the cell network. The device also keeps track of temperature and humidity.

The entire system can be controlled via a web interface. The Arduino serves a web page that allows the user full control over the alarm. With all of that, it’s hard to think of any more functionality to get out of this tiny microcontroller, unless you wanted to add a frickin’ laser to REALLY trip up the burglars!


Filed under: security hacks
Hack a Day 03 Sep 06:00

Easily test and experiment with GSM modules using AT Command Tester

Introduction

Working with GSM modules and by extension Arduino GSM shields can either be a lot of fun or bring on a migraine. This is usually due to the quality of module, conditions placed on the end user by the network, reception, power supply and more.

Furthermore we have learned after several years that even after following our detailed and tested tutorials, people are having trouble understanding why their GSM shield isn’t behaving. With this in mind we’re very happy to have learned about a free online tool that can be used to test almost every parameter of a GSM module with ease – AT Command Tester. This software is a Java application that runs in a web browser, and communicates with a GSM module via an available serial port.

Initial Setup

It’s simple, just visit http://m2msupport.net/m2msupport/module-tester/ with any web browser that can run Java. You may need to alter the Java security settings down to medium. Windows users can find this in Control Panel> All Control Panel Items  > Java – for example:

Once the security settings have been changed, just visit the URL, click ‘accept’ and ‘run’ in the next dialogue box that will appear, for example:

And after a moment, the software will appear:

Once you’re able to run the AT Command Tester software, the next step is to physically connect the hardware. If you’re just using a bare GSM module, a USB-serial adaptor can be used for easy connection to the PC. For Arduino GSM shield users, you can use the Arduino as a bridge between the shield and PC, however if your GSM shield uses pins other than D0/D1 for serial data transmission (such as our SIM900 shield) then you’ll need to upload a small sketch to bridge the software and hardware serial ports, for example:

//Serial Relay – Arduino will patch a serial link between the computer and the GPRS Shield
//at 19200 bps 8-N-1 Computer is connected to Hardware UART
//GPRS Shield is connected to the Software UART

#include <SoftwareSerial.h>

SoftwareSerial mySerial(7,8); // change these paramters depending on your Arduino GSM Shield

void setup()
{
  Serial.begin(19200);
  //Serial.println(“Begin”);
  mySerial.begin(19200);

}

void loop()
{
  if (mySerial.available())
    Serial.write(mySerial.read());
  if (Serial.available())
    mySerial.write(Serial.read());
}

Using the software

Once you have the hardware connected and the Arduino running the required sketch, run the software – then click “Find ports” to select the requried COM: port, set the correct data speed and click “Connect”. After a moment the software will interrogate the GSM module and report its findings in the yellow log area:

 As you can see on the left of the image above, there is a plethora of options and functions you can run on the module. By selecting the manufacturer of your GSM module form the list, a more appropriate set of functions for your module is displayed.

When you click a function, the AT command sent to the module and its response is shown in the log window – and thus the magic of this software. You can simply throw any command at the module and await the response, much easier than looking up the commands and fighting with terminal software. You can also send AT commands in batches, experiment with GPRS data, FTP, and the GPS if your module has one.

To give you a quick overview of what is possible, we’ve made this video which captures us running a few commands on a SIM900-based Arduino shield. If possible, view it in 720p.

Conclusion

Kudos to the people from the M2Msupport website for bringing us this great (and free) tool. It works – so we’re happy to recommend it. And if you enjoyed this article, or want to introduce someone else to the interesting world of Arduino – check out my book (now in a third printing!) “Arduino Workshop”.

Have fun and keep checking into tronixstuff.com. Why not follow things on twitterGoogle+, subscribe  for email updates or RSS using the links on the right-hand column, or join our forum – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other –  and we can all learn something.

The post Easily test and experiment with GSM modules using AT Command Tester appeared first on tronixstuff.

Tutorial – Arduino Mega and SM5100B GSM Cellular

Connect your Arduino Mega or compatible to the cellular network with the SM5100 GSM module shield from Tronixlabs. If you have an Arduino Uno or compatible, visit this page. If you are looking for tutorials using the SIMCOM SIM900 GSM module, click here.

This is chapter twenty-seven of a series originally titled “Getting Started/Moving Forward with Arduino!” by John Boxall – A tutorial on the Arduino universe. The first chapter is here, the complete series is detailed here.

Updated 18/01/2014

Introduction

The purpose of this tutorial is to have your Arduino Mega to communicate over a GSM mobile telephone network using a shield based on the SM5100B module from Tronixlabs. We’ve written this as the shield from Sparkfun used in the previous tutorial was somewhat fiddly for use with an Arduino Mega – so this shield is a more convenient alternative:

Our goal is to illustrate various methods of interaction between an Arduino Mega and the GSM cellular network using the shield shown above, with which you can then use your existing knowledge to build upon those methods. Doing so isn’t easy – but it isn’t that difficult.

Stop! Please read first:

  • It is assumed that you have a solid understanding of how to program your Arduino. If not, start from chapter zero
  • Sending SMS messages and making phone calls cost real money, so it would be very wise to use a prepaid cellular account or one  that allows a fair amount of calls/SMS
  • The GSM shield only works with “2G” GSM mobile networks operating on the 850, 900 and PCS1800 MHz frequencies. If in doubt, ask your carrier first
  • Australians – you can use any carrier’s SIM card
  • Canadians – this doesn’t work with Sasktel
  • North Americans – check with your cellular carrier first if you can use third-party hardware (i.e. the shield)
  • I cannot offer design advice for your project nor technical support for this article.
  • If you are working on a college/university project and need specific help – talk to your tutors or academic staff. They get paid to help you.
  • Please don’t make an auto-dialler…

 

Getting started

Before moving forward there us one vital point you need to understand – the power supply. The GSM shield can often require up to 2A of current in short bursts – especially when turned on, reset, or initiating a call.

However your Arduino board can only supply just under 1A. It is highly recommended that you use an external regulated power supply of between 9 and 12 VDC capable of delivering 2A of current – from an AC adaptor, large battery with power regulator, etc. Otherwise there is a very strong probability of damaging your shield and Arduino. When connecting this supply use the Vin and GND pins. Do not under any circumstances power the Arduino and shield from just the USB power.

Next – use an antenna! The wire hanging from the shield is not an antenna. YOU NEED THE ANTENNA! For example:

Furthermore, care needs to be taken with your GSM shield with regards to the aerial lead-module connection, it is very fragile:

Pressing the hardware reset button on the shield doesn’t reset the GSM module – you need to remove the power for a second. And finally, download this document (.pdf). It contains all the AT and ERROR codes that will turn up when you least expect it. Please review it if you are presented with a code you are unsure about.

Wow – all those rules and warnings?

The sections above may sound a little authoritarian, however I want your project to be a success. With the previous iterations of the tutorial people just didn’t follow the instructions – so we hope you do.

Initial check – does it work?

This may sound like a silly question, but considering the cost of the shield and the variables involved, it is a good idea to check if your setup is functioning correctly before moving on. From a hardware perspective for this article, you will need your Arduino board, the GSM shield with activated SIM card and an aerial, and the power supply connected.

Next you need to set the serial line jumpers. These determine which of the four hardware serial ports we use to communicate with the GSM module. Place a jumper over each of the RX1 and TX1 pairs as shown in the following image. By doing this the communication with the GSM module is via Serial1 in our sketches, leaving Serial for normal communications such as the serial monitor.

Make sure your SIM card is set to not require a PIN when the phone is turned on. You can check and turn this requirement off with your cellphone. 

For our initial test, upload the following sketch:

// Example 27.1

char incoming_char=0;      // Will hold the incoming character from the Serial Port.
void setup()
{
  //Initialize serial ports for communication.
  Serial.begin(9600);
  Serial1.begin(9600);
  Serial.println("Starting SM5100B Communication...");
}
void loop()
{
  //If a character comes in from the cellular module...
  if(Serial1.available() >0)
  {
    incoming_char=Serial1.read();    // Get the character from the cellular serial port.
    Serial.print(incoming_char);  // Print the incoming character to the terminal.
  }
  //If a character is coming from the terminal to the Arduino...
  if(Serial.available() >0)
  {
    incoming_char=Serial.read();  // Get the character coming from the terminal
    Serial1.print(incoming_char);    // Send the character to the cellular module.
  }
}

Then connect the GSM shield, aerial, insert the SIM card and apply power. Open the serial monitor box in the Arduino IDE and you should be presented with the following:

It will take around fifteen to thirty seconds for the text above to appear in full. What you are being presented with is a log of the GSM module’s actions. But what do they all mean?

  • +SIND: 1 means the SIM card has been inserted;
  • the +SIND: 10 line shows the status of the in-module phone book. Nothing to worry about there for us at the moment;
  • +SIND: 11 means the module has registered with the cellular network
  • +SIND: 3 means the module is partially ready to communicate
  • and +SIND: 4 means the module is registered on the network, and ready to communicate

All the SIND data and other codes the module will give you are listed in the AT command guide we suggested you download. Please use it – any comments such as “What’s +SIND:5?” will be deleted.

From this point on, we will need to use a different terminal program, as the Arduino IDE’s serial monitor box isn’t made for full two-way communications. You will need a terminal program that can offer full two-way com port/serial communication. For those running MS Windows, an excellent option is available here.

It’s free, however consider donating for the use of it. For other operating systems, people say this works well. So now let’s try it out with the terminal software. Close your Arduino IDE serial monitor box if still open, then run your terminal, set it to look at the same serial port as the Arduino IDE was. Ensure the settings are 9600, 8, N, 1. Then reset your Arduino and the following should appear:

The next step is to tell the GSM module which network frequency(ies) to use. View page 127 of the AT command document. There is a range of frequency choices that our module can use. If you don’t know which one to use, contact the telephone company that your SIM card came from. Australia – use option 4. Find your option, then enter:

AT+SBAND=x

(where X is the value matching your required frequency) into the terminal software and click SEND. Then press reset on the Arduino and watch the terminal display. You should hopefully be presented with the same text as above, ending with +SIND: 4. If your module returns +SIND: 4, we’re ready to move forward.

If your terminal returned a +SIND: 8 instead of 4, double-check your hardware, power supply, antenna, and the frequency band chosen. If all that checks out call your network provider to see if they’re rejecting the GSM module on their network.

Our next test is to call our shield. So, pick up a phone and call it. Your shield will return data to the terminal window, for example:

As you can see, the module returns what is happening. I let the originating phone “ring” three times, and the module received the caller ID data (sorry, blacked it out). Some telephone subscribers’ accounts don’t send caller ID data, so if you don’t see your number, no problem. “NO CARRIER” occurred when I ended the call. +SIND: 6,1 means the call ended and the SIM is ready.

Have your Arduino “call you”

The document (.pdf) you downloaded earlier contains a list of AT commands – consider this a guide to the language with which we instruct the GSM module to do things. Let’s try out some more commands before completing our initial test. The first one is:

ATDxxxxxx

which dials a telephone number xxxxxx. For example, to call (212)-8675309 use:

ATD2128675309

The next one is:

ATH

which “hangs up” or ends the call. So, let’s reach out and touch someone. In the terminal software, enter your ATDxxxxxxxx command, then hit send. Let your phone ring. Then enter ATH to end the call. If you are experimenting and want to hang up in a hurry, you can also hit reset on the Arduino and it will end the call as well as resetting the system.

So by now you should realise the GSM module is controlled by these AT commands. To use an AT command in a sketch, we use the function:

Serial1.println()

Remember that we used Serial1 as the jumpers on the shield board are set to connect the GSM module to the Serial1 hardware serial port. For example, to dial a phone number, we would use:

Serial1.println("ATD2128675309");

To demonstrate this in a sketch, consider the following simple sketch which dials a telephone number, waits, then hangs up. Replace xxxxxxxx with the number you wish to call:

// Example 27.2

void setup()
{ 
  Serial.begin(9600);
  Serial1.begin(9600);
  delay(10);
  Serial.println("starting delay");
  delay(30000); // give the GSM module time to initialise, locate network etc.
  // this delay time varies. Use example 27.1 sketch to measure the amount
  // of time from board reset to SIND: 4, then add five seconds just in case
}

void loop()
{
  Serial.println("dialling");
  Serial1.println("ATDxxxxxxxxxx"); // dial the phone number xxxxxxxxx
  // change xxxxxxxxxx to your desired phone number (with area code)
  delay(20000); // wait 20 seconds.
  Serial.println("hang up");
  Serial1.println("ATH"); // end call
  do // remove this loop at your peril
  { 
    delay(1); 
  }
  while (1>0);
}

The sketch in example 27.2 assumes that all is well with regards to the GSM module, that is the SIM card is ok, there is reception, etc. The long delay function in void setup() is used to allow time for the module to wake up and get connected to the network. Later on we will read the messages from the GSM module to allow our sketches to deal with errors and so on. However, you can see how we can simply dial a telephone. And here’s a quick video for the non-believers.

Send an SMS from your Arduino

Another popular function is the SMS or short message service, or text messaging. Before moving forward, download and install Meir Michanie’s SerialGSM Arduino library from here. Some of you might be thinking “why are we using a software serial in the following sketch?”. Short answer – it’s just easier.

Sending a text message is incredibly simple – consider the following sketch:

// Example 27.3

#include <SerialGSM.h>
#include <SoftwareSerial.h>
SerialGSM cell(19,18);

void setup()
{ 
  delay(30000); // wait for GSM module
  cell.begin(9600);
}

void sendSMS()
{
  cell.Verbose(true); // used for debugging
  cell.Boot(); 
  cell.FwdSMS2Serial();
  cell.Rcpt("+xxxxxxxxx"); // replace xxxxxxxxx with the recipient's cellular number
  cell.Message("Contents of your text message");
  cell.SendSMS();
}
void loop()
{
  sendSMS();
  do // remove this loop at your peril
  { 
    delay(1); 
  }
  while (1>0);
}

It’s super-simple – just change the phone number to send the text message, and of course the message you want to send. The phone numbers must be in international format, e.g. Australia 0418 123456 is +61418123456 or USA (609) 8675309 is +16098675309. And the results:

Reach out and control something

Now let’s discuss how to make something happen by a simple telephone call. And the best thing is that we don’t need the the GSM module to answer the telephone call (thereby saving money) – just let the module ring a few times. How is this possible? Very easily. Recall Example 27.1 above – we monitored the activity of the GSM module by using our terminal software.

In this case what we need to do is have our Arduino examine the text coming in from the serial output of the GSM module, and look for a particular string of characters.

When we telephone the GSM module from another number, the module returns the text as shown in the image below:

We want to look for the text “RING”, as (obviously) this means that the GSM shield has recognised the ring signal from the exchange. Therefore need our Arduino to count the number of rings for the particular telephone call being made to the module. (Memories – Many years ago we would use public telephones to send messages to each other.

For example, after arriving at a foreign destination we would call home and let the phone ring five times then hang up – which meant we had arrived safely). Finally, once the GSM shield has received a set number of rings, we want the Arduino to do something.

From a software perspective, we need to examine each character as it is returned from the GSM shield. Once an “R” is received, we examine the next character. If it is an “I”, we examine the next character. If it is an “N”, we examine the next character. If it is a “G”, we know an inbound call is being attempted, and one ring has occurred.

We can set the number of rings to wait until out desired function is called. In the following example, when the shield is called, it will call the function doSomething() after three rings.

The function doSomething() controls two LEDs, two red,  two green. Every time the GSM module is called for 3 rings, the Arduino alternately turns on or off the LEDs. Using the following sketch as an example, you now have the ability to turn basically anything on or off, or call your own particular function:

// Example 27.4

char inchar; // Will hold the incoming character from the Serial Port.
int numring=0;
int comring=3; 
int onoff=0; // 0 = off, 1 = on

int led1 = 9;
int led2 = 10;
int led3 = 11;
int led4 = 12;

void setup()
{
  // prepare the digital output pins
  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(led3, OUTPUT);
  pinMode(led4, OUTPUT);
  digitalWrite(led1, LOW);
  digitalWrite(led2, LOW);
  digitalWrite(led3, LOW);
  digitalWrite(led4, LOW);

  //Initialize GSM module serial port for communication.
  Serial1.begin(9600);
  delay(30000); // give time for GSM module to register on network etc.
}

void doSomething()
{
  if (onoff==0)
  {
    onoff=1;
    digitalWrite(led1, HIGH);
    digitalWrite(led2, HIGH);    
    digitalWrite(led3, LOW);
    digitalWrite(led4, LOW);    

  } 
  else
    if (onoff==1)
    {
      onoff=0;
      digitalWrite(led1, LOW);
      digitalWrite(led2, LOW);    
      digitalWrite(led3, HIGH);
      digitalWrite(led4, HIGH);  
    }
}

void loop() 
{
  //If a character comes in from the cellular module...
  if(Serial1.available() >0)
  {
    inchar=Serial1.read(); 
    if (inchar=='R')
    {
      delay(10);
      inchar=Serial1.read(); 
      if (inchar=='I')
      {
        delay(10);
        inchar=Serial1.read();
        if (inchar=='N')
        {
          delay(10);
          inchar=Serial1.read(); 
          if (inchar=='G')
          {
            delay(10);
            // So the phone (our GSM shield) has 'rung' once, i.e. if it were a real phone
            // it would have sounded 'ring-ring'
            numring++;
            if (numring==comring)
            {
              numring=0; // reset ring counter
              doSomething();
            }
          }
        }
      }
    }
  }
}

And now for a quick video demonstration. Each time a call to the shield is made, the pairs of LEDs alternate between on and off. Although this may seem like an over-simplified example, with your existing Arduino knowledge you now have the ability to run any function by calling your GSM shield.

 

Control Digital I/O via SMS

Now although turning one thing on or off is convenient, how can we send more control information to our GSM module? For example, control four or more digital outputs at once? These sorts of commands can be achieved by the reception and analysis of text messages.

Doing so is similar to the method we used in example 27.4. Once again, we will analyse the characters being sent from the GSM module via its serial out. However, there are two AT commands we need to send to the GSM module before we can receive SMSs, and one afterwards. The first one you already know:

AT+CMGF=1

Which sets the SMS mode to text. The second command is:

AT+CNMI=3,3,0,0

This command tells the GSM module to immediately send any new SMS data to the serial out. An example of this is shown in the terminal capture below:

Two text messages have been received since the module was turned on. You can see how the data is laid out. The blacked out number is the sender of the SMS. The number +61418706700 is the number for my carrier’s SMSC (short message service centre). Then we have the date and time. The next line is the contents of the text message – what we need to examine in our sketch.

The second text message in the example above is how we will structure our control SMS. Our sketch will wait for a # to come from the serial line, then consider the values after a, b, c and d – 0 for off, 1 for on. Finally, we need to send one more command to the GSM module after we have interpreted our SMS:

AT+CMGD=1,4

This deletes all the text messages from the SIM card. As there is a finite amount of storage space on the SIM, it is prudent to delete the incoming message after we have followed the instructions within. But now for our example. We will control four digital outputs, D9~12. For the sake of the exercise we are controlling an LED on each digital output, however you could do anything you like.

Although the sketch may seem long and complex, it is not – just follow it through and you will see what is happening:

// Example 27.5

char inchar; // Will hold the incoming character from the Serial Port.

int led1 = 9;
int led2 = 10;
int led3 = 11;
int led4 = 12;

void setup()
{
  // prepare the digital output pins
  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(led3, OUTPUT);
  pinMode(led4, OUTPUT);
  digitalWrite(led1, LOW);
  digitalWrite(led2, LOW);
  digitalWrite(led3, LOW);
  digitalWrite(led4, LOW);

  //Initialize GSM module serial port for communication.
  Serial1.begin(9600);
  delay(30000); // give time for GSM module to register on network etc.
  Serial1.println("AT+CMGF=1"); // set SMS mode to text
  delay(200);
  Serial1.println("AT+CNMI=3,3,0,0"); // set module to send SMS data to serial out upon receipt 
  delay(200);
}

void loop() 
{
  //If a character comes in from the cellular module...
  if(Serial1.available() >0)
  {
    inchar=Serial1.read(); 
    if (inchar=='#')
    {
      delay(10);
      inchar=Serial1.read(); 
      if (inchar=='a')
      {
        delay(10);
        inchar=Serial1.read();
        if (inchar=='0')
        {
          digitalWrite(led1, LOW);
        } 
        else if (inchar=='1')
        {
          digitalWrite(led1, HIGH);
        }
        delay(10);
        inchar=Serial1.read(); 
        if (inchar=='b')
        {
          inchar=Serial1.read();
          if (inchar=='0')
          {
            digitalWrite(led2, LOW);
          } 
          else if (inchar=='1')
          {
            digitalWrite(led2, HIGH);
          }
          delay(10);
          inchar=Serial1.read(); 
          if (inchar=='c')
          {
            inchar=Serial1.read();
            if (inchar=='0')
            {
              digitalWrite(led3, LOW);
            } 
            else if (inchar=='1')
            {
              digitalWrite(led3, HIGH);
            }
            delay(10);
            inchar=Serial1.read(); 
            if (inchar=='d')
            {
              delay(10);
              inchar=Serial1.read();
              if (inchar=='0')
              {
                digitalWrite(led4, LOW);
              } 
              else if (inchar=='1')
              {
                digitalWrite(led4, HIGH);
              }
              delay(10);
            }
          }
          Serial1.println("AT+CMGD=1,4"); // delete all SMS
        }
      }
    }
  }
}

And a demonstration video showing this in action.

Conclusion

So there you have it – controlling your Arduino Mega’s digital outputs via a normal telephone or SMS. Now it is up to you and your imagination to find something to control, sensor data to return, or get up to other shenanigans. This shield and antenna is available from Tronixlabs. If you enjoyed this article, you may find this of interest – controlling AC power outlets via SMS. And if you enjoyed this article, or want to introduce someone else to the interesting world of Arduino – check out my book (now in a third printing!) “Arduino Workshop”.

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The post Tutorial – Arduino Mega and SM5100B GSM Cellular appeared first on tronixstuff.

Tronixstuff 18 Jan 07:04