ATM (Smart ATM System)

Abstract

The development of automated cash handling systems has become increasingly important due to the growing demand for secure, efficient, and cost-effective currency exchange solutions. This project presents the design and implementation of an automated ATM prototype dedicated to intelligent cash exchange operations, supporting both accumulation and change-dispensing modes for paper currency and metallic coins. The system integrates multiple engineering domains including embedded control, pneumatic routing, dual-stepper arc positioning, servo-based coin gating, computer vision-based banknote recognition, pulse-based coin validation, and wireless inventory synchronization. Banknotes inserted by the user are captured and validated using a Raspberry Pi image processing subsystem equipped with controlled LED illumination and a servo-driven presentation mechanism. Validated currency is accumulated digitally before confirmation. For dispensing operations, a dual NEMA23 stepper-driven arc positioning mechanism aligns a vacuum suction assembly with the required banknote denomination. Selective airflow routing is achieved using normally-closed solenoid valves connected to a centralized vacuum system. Metallic coins are dispensed through servo-controlled 3D-printed gate mechanisms. The system supports hybrid transactions, allowing combinations of paper currency and coins within a single exchange session. Real-time inventory levels are synchronized automatically with a wireless administrator application via ESP8266 communication. Unlike commercial banking ATMs, this prototype focuses on intelligent denomination exchange and accumulation within a compact and educational mechatronic platform, demonstrating the integration of embedded systems, pneumatics, motion control, computer vision, and wireless monitoring into a unified architecture.