Hi there I am new to Arduino and need a little bit off help. I have build three models so far. One with network shield from notes mydooropener.com, one from www.instructables.com that work with sms and one with a call that drops for opening my garage door from arduino beeboard that is modified to work with sim900 shield/arduino uno and arduino relay shield. The only thing I now struggle with is to add an authorized user through sms on my last project. A scrip that allows you to send a sms from 1st position authorized number only saying 'add number' and he must return with 'type number to be added' and than run a AT Command to add the number. Hope someone can help. =(