Start a new topic

Problem with Raspberry PI SIM900 GSM/GPRS Add ON


I've buy a Raspberry PI SIM900 GSM/GPRS Add ON.

I'm trying to use the provided Library_Raspberry_SIM900 just to Send an SMS.

I really don't understand !? Your board seems to be fine but the library your provide to use it is full of bugs !?

I've finally managed to send a SMS but i had to modiy lots of code in the library. For instance, the part that sends  the sms body was commented in the SendSMS() function !!!!? The code did a Sigsegv when i began to use it due to a huge mistake in the ChangeIToS() function !!?

Is there another library somwhere ? May be the one i donwloaded was beta release ?

Thanks in advance.


Michel Cote.

3 people have this problem


Our Segnix Project provides a library for SIM900 GSM/GPRS Add-on. It has full support for SMS funcitons. 

You can download it at .


here is a library I recreated from original one with short manual.

it is working for me and have basic functions like call, send / read sms,...
if someone is going to add more methods please share updated library, for now this is sufficient for me, so I do not plan to add more by myself...



Hell, I have installed the Segnix library,  as you have indicated but there is no way to use it.

I have 2 questions for itead :

1° why do you not change the documentation link in your product page ( : people waste time with wrong documentation

2° is this so difficult to explain REALLY how to use the segnix library for the GSM shield for people using raspberry

I"m sure that the product (the shield) and the software (the segnix library) are good products but I can use them because lack of explanations...

I have had the 900A and Raspberry Pi 1 for almost a year now, and tried several sim cards. I use the serial interface with minicom. ATA+CGMM reports SIM900COM_SIM900A, AT+CGSN all look fine. But it always reports that the sim is not inserted. When I reboot it, it reports 'SIM not inserted' Is there some issue with using this in the US? Ting mobile says it could identify the IMIE.... Maybe an image showing exactly how to insert the sim, but I think I've tried every possibility.


We bought a set of Gboards to make a prototype. 

We are trying to activate the SIM900 module coping exactly the tutorial in your site but we are not succeeding.

We downloaded the libraries, we installed one of the exapmples to use serial console to comunicate with the SIM900 vía AT commands.
But the SIM900 is not responding.

What do you recomend to do? 

We wrote to last Friday. Please respond me as soon as possible.
Many thanks in advance,

Luciano Volpe

Follow the directions here to use the serial port:

There's a command to set the baud rate, you should not need it but try it if there's an issue.

Let us know.  Also, take a pic of how you inserted your sim card if you do get it working.



Login or Signup to post a comment