The objective of this complex engineering problem is to investigate and design a practical real world application that has following attributes:




The objective of this complex engineering problem is to investigate and design a practical real world application that has following attributes:

1.      The problem has no obvious solution and requires abstract thinking, originality in analysis to formulate suitable models.

2. This problem involves Interdependence and is a high level problem including many componentparts and sub-problems.

This problem will design and simulate a coin operated vending machine.


Complex Engineering Activity Outcomes (CEAO): 

Through the course of this engineering activity, students should be able to partially attain some or all of the following graduate attributes:

1. GA1: Engineering Knowledge

2. GA2: Problem Analysis

3. GA3: Design/Development of Solution

4. GA4: Investigation

5. GA5: Modern Tool usage

This activity is mapped on CLO2 and your performance in this project will play an important role in the attainment of this course learning outcome.   .



Apply acquired problem-solving knowledge both in individual capacity and teamwork to reproduce results.





Task Goals:

The goals of this engineering problem are to:

1. Design a digital circuit according to given specifications.

2. Gain experience with modern CAD techniques used to design digital systems.

3. Learn how to get information from professionally written manuals (e.g., 7-Segment)

4. Learn to test designs with simulation.

5. Learn to perform physical testing.

6. Learn how to work in a team.

7. Learn how to write a project report.


Problem Statement:

You have to design and simulate a circuit for a vending machine using switches, lamps (LEDs) and seven-segment displays. The following design specifications are to be followed:

·         The vending machine takes two types of inputs, coins and choice of product.

·         The vending machine should accept and differentiate between different money denominations. Assume that there are only 1, 2, 5 and 10 rupee coins available. The different type of coins can be denoted by four different switches.

·         This machine sells 8 different type of products, each with different prices. None of the products can cost exactly 1, 2, 5 or 10 rupees. Choice of product can be indicated by toggle switches. Users are only allowed to purchase 1 product at a time.

·         Two types of outputs are generated by the vending machine; indication of product purchased and the amount of change that needs to be returned.

·         One out of 8 LEDs for each product should light up indicating a successful purchase. Another LED should light up if the input money is less than the price of any desired product.

·         The amount of change that needs to be returned must be displayed on 7 segment displays.

·         Once the money credited to the user is returned, the vending machine should be able to reset the money counter while triggering an LED to indicate change has been returned. A new product could then be purchased.

·         The vending machine design should be able to keep track of inventory in the machine. It can be assumed that in the initial state, the machine is full and there are five items for each of the 8 selections.



You are supposed to submit the following deliverables by the deadline: 

      Hardware implementation of the sequential vending machine

      Detailed report on the design and working of the vending machine

      Simulation circuit on Proteus

Each group will have to present their project on the above-mentioned date.

Report Instructions:

Your written report should be concise and professionally written. It is expected that you will follow the provided format closely. Departures from the format may result in deduction of points from your grade. The task report must contain the following sections:

1. Task Description: This section should describe your design. It should provide the reader with information he would need to understand how the circuits work and how you designed them.

2. Theory of operation: Explain how your circuit works, but do not give implementation details. This should be an expanded version of the introduction. That is, give a high level description of what your circuits do and how they do it. For example, you could explain any conditions or restrictions the user must observe to use the circuits, and the high level structure of your circuits at the block diagram level. 

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