Sending and Receiving SMS with a SIM800 GSM Module - Tutorial (#124)

The SIM800 is a low cost SMS module that you can use in electronic/IoT projects. It does have a few quirks, though. I set one up here and show how to send and receive text messages. See also: Tutorial on the SIM900 modue: https://youtu.be/KVI7BhXEJ3o Tutorial on the M590 module: https://youtu.be/IB7JVZKDjyI My github site: https://github.com/magiccow/sim900 AT command reference for the SIM800: https://www.elecrow.com/wiki/images/2/20/SIM800_Series_AT_Command_Manual_V1.09.pdf