He decided to go with the low-cost SIM800L GSM modem, but as it only works on 2G networks, provisions have been made in the board design to swap it out for a more modern module should you desire.

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 ...

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 ...