Generator status controller with SMS sending

The customer received a task:
It is necessary to corrolate the presence of the voltage on two lines - one main on which sometimes the voltage is missing,and second-step,which is connected to the generator.And it is also necessary to notify the owner by SMS in case of the voltage is missing.It was manufactured a device based on Arduino Nano и SIM900A module.Control is produced by two lines and in case of failure to the main line of voltage,controller awaits a certain time and asks the line with the generator.In case if the generator launched-controller sends a SMS about that the generator launched,that the owner knew when this happened and could calculate the time to repair.In the event that there is no voltage on the generator line, the controller will send a SMS with a notification that the generator has not launched after the voltage on the main line is missing, and it is worth checking it.The controller was performed on the installation plate,installed isolated power block from Hi-Link, was added battery to that after the loss of voltage,the controller was able to send SMS and monitor the state of entries.There is the possibility to scale and expand the functionality of the device.