Browsing by Author "Ahmed Ali, Abdurahman"

A design and prototyping of a system that dispenses postal stamps in exchange of coins. This system is a vending machine contained in box-shaped housing embedded with a microcontroller as a brain for the system. The front face of the machine includes an LED for indicating the machine is ON, push buttons for receiving user selection of stamp type and quantity, LEOs for indicating availability of stamps and slots for coin and stamp entrance and exit. The housing contains a coin detecting device, stamp dispensing stepper motors and control circuitry. The coin device is made of LDR sensors attached to a channel for the coin. Each motor is connected to roller shaft to handle the stamps. The control circuitry consists of two sections: a PIC circuit where the rnicrocontroller is mounted on and a circuit for the motors drivers ICs with resister and diodes.