I have a project using a arduino micro to control some shift registers as well as communicate with a uart serial device with a software serial port. A pc based software application I developed send commands to the atmega which in turn either affects the state of a relay or sends a pre-packaged message to the serial device. currently there is no bi-directional communication between the application and arduino. adding this is not a issue and is in the near future.
I would like to use a gsm shield that I have, connected to the arduino via another software serial port to enable and disable the hardware. I would also be the same mechanism for re-enabling the hardware. my concerns and what I am looking for help on is...
how would I check the gsm modem all the time for any new messages and how to parse them for the "code" sent how would I retain a memory even with a power cycle that the current state of the arduino is "diabled" or "enabled" how would I trigger something in the code so that the serial port reports to the software application the hardware is "on" or "off"
any suggestions would be great! thanks