Industrial Vending Machine project based on PIC16F882 microcontroller developed in C-Language. Debugged and simulated using MPLAB X IDE (v6.05) and Proteus Simulator
- PIC16F882 Microcontroller: the microcontroller used to implement the project using a very limited 2 KB Flash for the program and 128 Bytes RAM
- LCD Display Screen: provides instructions and information to the user such as selected drink type, price, current balance and any change due
- Push Buttons (3-PB): simulate inputs required to drive the user interface for drink selection and also to simulate coin insertion
- Potentiometer (VR2): simulate the voltage output of an analogue tilt sensor used for anti-theft detection
- LEDs (2-LEDs): simulate control outputs to the drink and coin dispensing mechanisms
- Alarm Buzzer: under normal operation this mode is dormant. However, when the tilt sensor voltage exceeds 2V ... it will indicate theft.
The Project presents the software development of an Industrial Vending Machine that has 6 fundamental modes:
- Drink Selection Mode: the initial state that provides a user interface through which the customer can select a drink and view the prices
- Coin Insertion Mode: must initially display the cost of the selected drink. Coin insertions are simulated by pushbuttons (SW0-2). After each coin insertion the display updates to show the outstanding balance
- Dispense Drink Mode: this is simulated by setting LED output RA0 HIGH for 5 seconds, Timer 0 is used to create the delay of 5 seconds and after time has elapsed RA0 is set to LOW
- Dispense Change Mode: this mode is ONLY active if the inserted coins exceeded the required balance for the selected drink, by using RA1 LED to simulate coin dispense
- Drink Ready Mode: this mode is the final one, where a message is displayed on the LCD for 5 seconds then the system resets to start over for the next customer
- Alarm Mode: if the voltage from VR2 exceeds 2V, simulating a tilt sensor, an alarm is activated (RA3).
Note that the buttons are functional at Drink Selection Mode and Coin Insertion Mode, where in Drink Selection Mode SW0 moves to the next drink and SW1 selects the currently displayed drink. and in Coin Insertion Mode all buttons are functional adding 10 - 20 - 50 coins respectively.
Simulation schematic and video illustrating the vending machine operation
