I'm not sure if this is the right place to send this post. If not, please let me know (and to the admin : please move it in the right section).
My questions are :
what are the different GRPS / GSM modules and shields that exist ?
what's the difference between them ?
is there a library to use them ?
which one is the most popular ? (thus it will be easier to find tutorial and projects)
For more informations :
I want my Arduino to send me an SMS when I send an SMS request to it (with a requesting word for example) or on a regular basis (like every hour, or day, etc.).
The SMS sent by the Arduino would contain values read from a GPS chip (that I need to find as well) or any other sensor (light, acceleration ... you name it).
So for example : I leave this module in my car. The board is connected on the battery (it shoudn't drain too much from a car battery, right ?). One day my car is being stolen. I send an SMS to it and the repply I get is the position, speed, etc.
... But it could be something completely different : I connect a motion detector (e.g. PIR, passive infrared receiver) on my Arduino board. I leave it in front of my entrance door. When the board detect a movement, then it sends an SMS. And if it's not just me entering my house, then ... well, maybe I should worry
Additional comment : I've searched the forum. a solution is to use a T68 (an old phone). but I prefer a board. then I can see people using different boards but considering the cost, I'd rather ask for additional advices.
Instead of using a GSM or GPRS module to send SMS why don't you just get an ethernet shield and send an email to your SMS gateway? It would be much easier and a lot easier to expand functionality wise. You could implement this easily with simple web programming.
Clarification
Your ethernet capable Arduino would report real time sensor values to a web server and then the webserver could send an SMS to you and allow two-way communication.
It is actually a good solution and I thought about it if I'm using the project indoor, at home, where I have internet and an ethernet network (however I looked into sending an email through a secured SMTP and it doesn't look that simple).
But, I was more looking for some solution really wireless.
I'm taking again the example of the car. I would like to leave the module in the car and be able to text it so it would repply me with it's position. So GPRS with SMS support sounded like appropriate. So I'm still looking for infos on GPRS/GSM shield to send SMS
But I agree with you (and thanks for your answer)! If I'm using this concept to monitor something at home : the ethernet shield would be good. I could be monitoring many things ; humidity, light, motion with PIR, moisture in my plants, openned door, noise, etc.
If I stay on this concept : I have the same question for a wifi shield.
Regarding the complicity of sending an email through SMTP - it really isn't that difficult. All you would need is some kind of intermediary layer to communicate with the Arduino and process the web/mail requests.
Here is an example of sending mail with Python through an existing GMAIL account.
Communication with the Arduino is easily done over a serial connection. Well python has a very simple to use serial library. Look her for examples of serial communication between Python and Arduiono. http://www.arduino.cc/playground/Interfacing/Python
If you desperately need connectivity all the time then how about just purchasing a cheap phone with paid minute cards. You could make it even easier by finding a cheap android phone and using it to send data over a mobile network. Cricket has incredibly cheap plans with a certain amount of data usage and minutes available.
Communication between android phone and Arduino can be achieved in a multitude of ways.
I'm new to Arduino, but had a similar idea to yours. I want to use gsm system to monitor conditions and alarms in my remote vegetable garden (allotment) and storehouse (shed).
I found this tutorial on an Arduino shield. It looks useful, but I am not sure. Worth a look though.
