Modernizing Commercial Signage: Low Memory Bluetooth-based Android Control of Display Panels

Numeric display boards are common in banks, hospitals, petrol pumps, and public areas, but their updating process through manual methods or serial communication is error prone, time consuming, and unsuitable for frequent changes. This paper presents a secure Bluetooth based Android solution that allows remote updating of seven segment displays using a simple interface. The proposed system integrates a password protected Display Control Unit, Decoder Board, and multiple Display Boards with both Bluetooth and UART communication for reliability. The implementation achieved optimized memory usage of 47% of Flash, 65% of SRAM, and 31% of EEPROM, enabling deployment on low cost microcontrollers. The developed prototype successfully managed up to 64 panels with accurate and secure control. This work improves the efficiency and flexibility of numeric display management while providing scalability for future extensions such as IoT connectivity, multilingual display support, and solar-powered operation.