Raspberry Pi enthusiasts interested in learning how to send and receive SMS messages using their Pi mini PC, may be interested in a new article published over the holiday season by Hackster.io user “cb77”. The project allows your Raspberry Pi to send and receive SMS, as well as enabling you to send commands to the mini PC to carry out specific actions. The project has been classed as an intermediate skill level build and should take approximately 60 minutes to complete once you have attached and setup your modem to the Pi.
“I use a modem connected to a raspberry pi 2 B, to receive the status of one system connected to the raspberry. The Raspberry read the sensors and send a SMS with the information whenever the sensor cross a defined threshold, Also I can send commands by SMS to the raspberry to do specific action like, force the reception of the status, know if the system is running or reboot the raspberry. I wrote this code in C but I also create a class in C++. The code is very simple first: I setup the modem and send the proper AT commands to setup the SMS.”
“Then I create thread to receive the SMS and identify the commands. No all phones can send commands or ask for info, they must be in a list of authorized number, if they are not in the list, the code is rejected the SMS. Once the SMS command is accepted, you have to create a loop (i.e. while()) to process the commands received in the SMS. You can add as many commands as you want in the receiving and processCommand functions. I used pthread and wiringPi libraries so you have to compile it like this : gcc -o main main.c -lwiringPi -lpthread”
Source : Hackster.io