A simple SIM900 with PIR alarm notification and relay control via sms
Please download and install library with test code first:
http://www.tinyosshop.com/datasheet/GSM_GPRS_GPS_Shield_GSMSHIELD.rar
Product info: https://www.tinyosshop.com/arduino-gsm-shield
Pin usage on library:
D2, D3 for Rx, Tx D7 for Ring Indicator D8 power D9 reset