Vending Machine using FPGA

  Vending machine is an automated machine that dispenses items based on the selected product and input token or coins.

Model used : Mealy state machine model

Programming: Verilog

Simulating Software: Xilinx VIVADO 2017.4

Hardware: Nexys 4 DDR FPGA development board. 

The project is perfectly programmed to give outputs that clearly tells the user on the product to be dispensed, change to be given and the availability of the product. Additionally, delay function is also been implemented.

Design Flow / Algorithm : 


Designing Mealy State Diagram :

Unlike adding the number of states based on the product cost, I've executed using less number of states.

Here, I've considered two products of price Rs15 , Rs20.The below image depicts their respective mealy state diagram.
 


Simulation Results: 

Considering the availability/count of two products, the below are the results for the given input.

  • Input 1: Without Delay
    Rs:10+10     -->Required Product-1
    Rs:5+10+10 -->Required Product-2
    Rs:10+10     -->Required Product-2
    Rs:5+10       -->Required Product-1
    Rs:5+10       -->Required Product-1
    Rs:10+10     -->Required Product-2

  • Input 2: With Delay
    Rs:10+10+0      -->Required Product-1
    Rs:5+10+10+0  -->Required Product-2
    Rs:10+10+0      -->Required Product-2
    Rs:5+10+0        -->Required Product-1
    Rs:5+10+0        -->Required Product-1
    Rs:10+10+0      -->Required Product-2

HARDWARE IMPLEMENTATION 

For one product if Rs.15

Hardware :

REFERENCE PAPER:

  • vE. Kho and M. Kumar, "Design and Implementation of FPGA based Vending Machine for Integrated Circuit (IC)," 2020 International Conference on Communication and Signal Processing (ICCSP), 2020, pp. 0246-0251, doi: 10.1109/ICCSP48568.2020.9182375.
URL: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9182375&isnumber=9182042
  • vM. Suthar, "A Novel Implementation of FPGA Based Smart Vending Machine," 2021 IEEE International Conference on Technology, Research, and Innovation for Betterment of Society (TRIBES), 2021, pp. 1-6, doi: 10.1109/TRIBES52498.2021.9751636.
URL: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9751636&isnumber=9751452
  • vV. Vaid, "Comparison of different attributes in modeling a FSM based vending machine in 2 different styles," 2014 International Conference on Embedded Systems (ICES), 2014, pp. 18-21, doi: 10.1109/EmbeddedSys.2014.6953042.
URL: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6953042&isnumber=6953037