Design of a GSM-Based Electronic Notice Board: System Architecture, Message Validation Logic and a Verification Protocol

This report presents the design of a notice board that is updated remotely by SMS over the GSM network. The design combines a GSM module with a SIM card, a microcontroller, a character LCD and a regulated power supply. When an SMS arrives, the controller checks that the sender is authorised and that the message follows a set format and length limit before it replaces the displayed notice. Invalid messages leave the current notice unchanged. The report covers the architecture, interfacing issues for power and serial logic levels, the message handling algorithm, a layered security approach and a verification protocol of eight tests. It is a design report from an undergraduate project, and no measurements from a working prototype are reported.