New idea for security of roadside toilets in Finland. The system will open the door of the toilet only in case, when SMS is sent to specific number which is displayed at the door. So, opening will cost just like a normal SMS and all you have to do is to send text “OPEN”. The call is directed to modem which will sound a buzzer and open the door.This should prevent vandalism, because people will be identified with their mobile phone number. Link
7innovation 