Using SIM card with ARDUINO.


I want to use a SIM card in arduino, to turn on a system.

This is my application: I want to save phone numbers in arduino's memory and using GSM module -e.g to open and close garage door-. If i called the arduino SIM, arduino must compare the calling number with saved numbers, if it's exists in the memory, arduino opens the door. Else, arduino doesn't respond.

What's the best GSM module to use in this application?? and can you help me to construct the code??

I doubt anyone will help you to construct the entired code. Things that I learned from this forum is that, you need to do your own homework first, and when you are stuck, you refer to the forum or open a new thread. Give as much as information as you can and wait for the PROS to reply.

You can start with GSM examples. It is in GSM library as part of Arduino SW. Some GSM shield is offered by Arduino. Look at the products for information.

MohammadAsmar: What's the best GSM module to use in this application??

One that does [u]not[/u] use pins 2,3 for software serial.

Pins 2,3 are used for external interrupts and, on a Uno at least, they are the only ones available. A GSM shield has nothing to do with external interrupts but, if it hogs those pins, it means you are in strife if you need them for that purpose. Meanwhile there is a swag of other pins that are just fine for software serial.

You may never need external interrupt, or even know what it is, but you might need it some day, and it is never a good idea to encourage shield designers who are morons.

I'm using the SIM800L module. You can make calls or even HTTP requests. There are many libraries for making and managing incoming calls. I've created this library but it only works with HTTP stuff. Hope it helps :)

You can use a Nimble link modem model #nl-sw-lte-tnag-b. I wrote some code to work with the modem that could easily be modified to do what you propose. I could help you with that code if you like. To see the basics of the modem connection see The basic code is available for download at Let me know if you need help modifying the code to work, you can get my contact information from the git-hub link above in the comments of the code of the README.txt file.