It is very easy to build an “SMS-controlled relay” with the help of a cheap GSM modem module and a small microcontroller board. Here, I’m using the SIM800L and Arduino Nano V3 to develop a nifty ...

SIM800L GSM module library for Linux systems like the Raspberry Pi. This library was also successfully tested with SIM800C and should also support SIM800H. This library provides a driver for SIMCom ...