Intro to the SIM800L. If you are looking for a compact GSM/GPRS module, you can get the SIM800L from most eBay traders. It is not the most judicious choice, but you can build your own basic GSM ...

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 ...