POPCORN MACHINE - ece.usu.edu Final... · presented and final conclusive comments will be made including the accomplishments of the design ... A brief explanation of the ... Design

POPCORN MACHINE

SENIOR DESIGN PROJECT PROPOSAL

ECE 4850: DESIGN III

May 5, 2008

JOHN E. ARUMA

Instructor Approval ________________________________________ __________________

Dr. YangQuan Chen DateElectrical and Computer Engineering

DepartmentUtah State University

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Table of contents

1 INTRODUCTION ....................................................................................................................... 3

2 PROBLEM DEFINITION .......................................................................................................... 3

3 OBJECTIVES.............................................................................................................................. 5

4 DELIVERABLES........................................................................................................................ 6

5 ENGINEERING APPROACH ................................................................................................... 7

5.1 Project Description .............................................................................................................. 8

6 PROJECT MANAGEMENT...................................................................................................... 9

6.1 Tasks................................................................................................................................... 11

6.2 Time Management and Scheduling.................................................................................. 23

6.3 Budget ................................................................................................................................ 24

7 CONCLUSION.......................................................................................................................... 25

8 ATTACHMENTS...................................................................................................................... 26

Table of FiguresFigure 1 Popcorn Controller comparison 7Figure 2 Tradition method 7Figure 3 Flow diagram 8Figure 4 Preliminary Block diagram 9Figure 5 Power diagram 10Figure 6 Schematic diagram of a microwave 10Figure 7 Schematic of modified oven 11Figure 8 Block diagram of Popcorn Controller 12Figure 9 Software flow diagram 14Figure 10 Sample GUI Screenshot 15Figure 11 Popup screen shots 16Figure 12 Signal processing module 17Figure 13 Filtered signal plots 18Figure 14 Modification section block diagram 22Figure 15 Gantt Chart 24Figure 16 Table of costs 25



Abstract

This project entails the design of a popcorn machine, which requires popcorn kernels, a microwave, a micro-

controller and sound sensors. A graphical user interface (GUI) would be used for popping frequency monitoring

and accurately determine when the popcorn is ready without burning the kernel. In the future, this project will

act as source of advice for manufacturers and users on the popping of the popcorn. This proposal will define the

project's objectives, constraints, deliverables, engineering approach, budget , and management.

1. INTRODUCTION

The design develops a systematic approach of popping to keep kernel from burning. This project is expected to

provide user-defined parameters from popping, demonstrating and determining popping frequency.

Usually when popping using pop corn machine, the popcorn timer option is not definite because someone

has to watch or guess as to when exactly the popcorn will be ready. This project comes in handy as it uses the

popping sound of the popcorn to determine if it is ready and hence, not burn the kernel.

2. PROBLEM DEFINITION

Popcorn manufacturers rarely inform users about exactly what times should be used in a microwave. According

to Michael and Mehmet in the book (YOU: On a Diet). Popcorn needs to be heated for five to six minutes. The

author further insists “don't burn it!”, The motivation of this project to enable users to pop popcorn without

worrying of burning corn instead relax until the popcorn is ready for enjoyment.

What exactly happens when a kernel is popped using a microwave? Knowing the principle of the process leads

to finding out the solution, which is, of course, not burning the kernel.

Tossing a flat pouch of popcorn kernels into a microwave for about three minutes results in the expansion of

volume to 40 or 50 times greater than the original volume. When a popcorn kernel heats up, the moisture inside

the kernel expands.



There are three elements that make popcorn work.

1. Moisture inside the kernel

2. Starch inside the kernel

3. The hard shell surrounding the shell.

During the heating of the popcorn, in a microwave, the moisture inside the kernel expands. Moisture parameter

is vital to the popcorn kernel; unless the percentage of the moisture in the kernel is in the right proportion, the

kernel won't pop. When the pressure inside the hard shell becomes high enough, the kernel explodes.

Overcooking the popcorn, results in an unfavorable aroma and inconsumable popcorn. Analysis of the popcorn

popping sound frequency leads us to a new method of popping corn. The new design using Popcorn Controller

pops the corn at right time limit for the best quality. This design uses sound signal of pops to determine whether

the corn is ready hence switching off the microwave.

Summary of Design Process

The report contains the conclusion of the documentation detailing all of the design details integral to the

solution of popping or burning kernels. It covers the testing of DSK board, Reed Relay DIP switch, developed

GUI and also the refinement of entire design. The outcome of the design is a working prototype which if

scheduled to the next design process of mass production. The preliminary design and implementation phases of

this design are discussed in details herein.

Summary of results

The resulting elements of this design process could be categorized into the three sections: working design

consisting of a hardware section, the actual design that includes software design, and the finished design that

includes interpolation of hardware and software to come up with a pop corn controller system. The design of

Popcorn controller system was a complete success.



3. OBJECTIVES

The aim of the design is to:

• Develop an effective pop counter

• Develop control algorithm

• Use of PC Monitoring

• Use a Micro-controller to implement design

• User defined parameters

4. DELIVERABLES

To achieve this objective, the following are required, ranging from hardware to software section. The hardware

sub-sections include:

• PC interface: includes microcontroller interface, which would be interfaced with the microwave so that

it will turn off as soon as the maximum popping is achieved.

• Sound sensor: will detect popping.

• Microwave: used as popper for the popcorn.

• Control Output Monitor: will display the results on the time basis or output as expected.

The software subsections include:-

1. A counting and control algorithm,

2.A GUI and software.

3. A signal processor

The signal processor will be useful on analyzing the sound wave file so that the algorithm desired is obtained

e.g. the time constant K=R + ôR2 expression would be used to obtain the desired results for the least amount of

time for the optimum popping of popcorn without burning the kernel.



Social Implications

This design will change people’s lifestyles, as users will be able to pop popcorn without having to pay attention

or stand next to microwave for fear of burning the kernels. The popcorn Controller could be incorporated to the

normal microwave design or sold separately. Incorporating the Popcorn Controller into the microwave design

will raise the cost of microwave with a 5% margin:- the convenience and the purpose surpasses the cost

implications. A separate Popcorn Controller is 10% cost price of a Microwave.

Report Organization and Summary

The next sections of the design indicate the design process, addressing the preliminary design, ranging from

block-wise description to component level description. The decisions made to achieve the desired results will

be discussed and the final design tested and implemented. The project management and final budget will be

presented and final conclusive comments will be made including the accomplishments of the design and further

refinement if needed.

5. Engineering Approach

Preliminary design

This section consists of brainstorming on different ideas on how to design a Popcorn Controller. Different

techniques suggested were vetted. The main objective was to create a scalable design without compromising the

main objectives. The different methods of popping popcorn without burning the kernels;- flouted included:

Manual popcorn monitoring

Time setting on the microwave

Popcorn Controller machine

Manual popcorn monitoring;- requires a user to watch the microwave in case the pop corn burns. It requires

diligent and patient monitoring of the pop corn.



The Time setting technique;- requires the user to guess on time that pop corn bag will be fully popped without

burning the kernel. This techniques performance is pegged on chance of guessing the right time of popping the

corns.

Pop controller Machine:-This method uses frequency and a counting algorithm, which counts the number of

seconds after majority of popping. After a well established number of counts, the system will switch off the

microwave automatically after right popping without burning kernel.

The merit of each method was evaluated against the design objectives using the pair-wise comparison chart in

Figure 1.

If the goal listed in the row is more important than the goal listed in the column, a '1' is entered at the

intersection of the respective columns. The relative score is read from the far right column, with a higher

number being more desirable. Comparing the three methods respectively, the Pop corn controller method

emerged as feasible and useful as it required less manual interaction, was fast and resulted in un-burnt popcorn,

this is evident with total points being 7 pts compared to 3 points for the manual method.

The figures below illustrate the findings

Goals Accuracy Fast User friendly Inexpensive ScoreAccuracy XXX 0 0 0 0Fast 1 XXX 1 0 2User friendly 1 1 XXX 0 2Inexpensive 1 1 1 XXX 3Total Points 7

Fig 1: Pair-wise comparison of Pop corn Controller machine.

Goals Accuracy Fast User friendly Inexpensive ScoreAccuracy XXX 0 1 0 1Fast 0 XXX 0 0 0User friendly 0 0 XXX 1 1Inexpensive 1 0 0 XXX 1Total points 3

Figure 2. Traditional method of popping corn



The following is the preliminary algorithm diagram of the project:

Figure 3. Preliminary flow diagram of popcorn design

A device is required to detect the sound signal from the microwave which conveniently is microphone. The

sound signal detected from the microwave is fed to the microcontroller, which implements a new algorithm that

implements the Popcorn Controller. After the objective is achieved, there will be improved microwave user

interface, monitoring popping using a PC, and success of implementing the controller using the on-board

microprocessor.



Figure 4 shows the preliminary basic block diagram.

Figure 4. System Preliminary block diagram.



Figure 5. Preliminary power diagram

The figure above shows the power flow to the microwave. Controlled by a reed relay switch.

Figure 5 shows typical microwave oven, the change made to switch (SW3) determines when to turn ON/OFF

the microwave.

Figure 5. Schematic diagram of a typical microwave



A brief explanation of the circuit operation of the microwave oven is required so that the modification

suggested using the Popcorn Controller is understood.Generically Sw1 is the primary interlock switch (upper).

Sw2 is the secondary interlock switch. R1 is the monitor resistor. Sw3 is the interlock monitor switch. M1 is the

geared motor for the turntable where (the food to be cooked sits). M2 is a motor for the fan which draws air

through the oven and magnetron. Connected in parallel with M1 and M2 is the cavity lamp, which lights whilst

food is cooking. Fs2 is a high voltage fuse (typically 0.7A and 5kV breaking capacity). C1 is a high voltage

capacitor. D1 is a high voltage diode. The point of interest is the SW3 switch which is normally open. Instead of

using this switch as usual, this project introduce the Reed relay DIP switch, which would accept low voltage

from DSK board and turn on and off the Microwave as programmed, into the board.

The modified circuit diagram is shown in Figure 6.

Figure 7. Schematic of modified oven

After the modifications discussed above are made, the final design block diagram is finished as shown in Fig 8



Figure 8 Popcorn controller block diagram

Design Specifications and Performance Criteria.

Hardware section

The block diagram in Figure6 is broken down as follows:-

Inputs: Sound sensor, Microwave power.

A sound sensor or a microphone was the best choice due to factors including cost, availability, and how it fitted

on the existing design in the chosen microwave. A microwave was purchased for implementation and

demonstration purpose.

Processing Section: A/D converter, CPU and I/O included within DSK Micro-controller.

This subsection includes conversion of analog signal to digital signal i.e. the analog signal popping sound is

transformed to a quantized discrete signal with less SNR. This section includes the hardware interfacing of the

input signal to the output device while taking into account the hardware interrupts requests.



Output section: Popped popcorn, PC GUI

This subsection consists of the product desired or end result. It’s the expectation from the user. It includes the

ready popped popcorn. Visual display the popping frequency and playing of some kind of music at the end of

the popping. There will be a pop up from the GUI indicating to the user that the popping is done or a warning to

not open the microwave during the popping period.

Software Algorithm

The choice of the programming language was dictated and supported by the board. The viable option with

respect to DSK board was C/ C++ language which enables communication between the systems. The

programming language is directly interfaced with MatLab by using #include ‘engine.h’ routine. This

information will be embedded inside the micro-controller chip for operation. This section entails popping

algorithm, development environment, and GUI improvements.

The popping algorithm consists of popping by time, popping by percentage and pop by average number of

kernels by bag size. The development environment consists of windows XP SP2, code composer studio-

developed by Texas Instruments interfaces with a TI DSP board.

Flow decisions are illustrated in the Figure7



Figure 9. Software decisions flow diagram

Explanation:

The Figure 9, above shows data flow diagram of a Popcorn Machine. During the start up period there is a wait time delay

of 15 seconds. If the popcorn begins popping, the counter should start counting; if not, then the counter should continue

waiting until it starts. As soon as two minutes of popping elapse, the microwave should switch off else continue

incrementing the counter until when it reaches 2 minutes. When the optimum time is reached the microwave switches off,

resulting in un-burnt popcorn.



The Figure 10, shows plots of popping frequency and pop ups indicating different scenarios ranging from popping

frequency, sampling, and time delay for popping.

The screenshot below shows what the GUI will look like. The two criteria of popping are: popping by

percentage (i.e. popping the average number of kernels by bag size) and popping by maximum (popping the

maximum number of kernels without burning according to the sizes chosen). The black empty screen will

display the popping frequency if the user wants to view.

Figure 10. Sample GUI screenshot



When the popping is complete, the pop is displayed on Figure 8. Would be displayed on the screen of the

users’ PC .

If the microwave is opened accidentally or intentionally, the pop-up displayed on the screen.

Figure 11. Pop-up screen shots



Signal processing section

The following diagram depicts on how the signal is received processed and then output in voltages levels that is

used to control the turning ON/OFF of the microwave.

Figure 12. Signal processing module

The sound source is the sound of the kernels popping in the microwave detected by the microphone. The input

signal is 0-1.6mV peak-to-peak(0-1.6mV Pk-Pk), converted to digital signals in the AIC codec, filtered, and the

signal is analyzed using FFT, a counting algorithm runs by sampling signals within a window of 5 seconds and

output through line output with signal amplitude of 1V peak-to-peak(1Vpk-pk).

The filtering process includes;- use of the band pass filter of sound frequencies of 5-8Khz.Filtering will send

results to the establishment of threshold by counting pops by mean squared amplitude threshold. The counting

algorithm used is implemented by establishing time constant, ô, from the expression K=R+ôR2

This comparison of signal to noise ratio was found that Raw SNR power = 0.1dB, while filtered

SNR = 17.6dB.The following plots obtained from MatLab indicate the different signal aspect before and after

filtering. Figure 10 below shows a plot of raw signal with respect to frequency in Hz versus Time in seconds.



The Figure 13(a), Plot of filtered signal,

The yellow section is predominantly noise while the red strips indicated the pop signal all plotted on filtered

signal with respect to frequency versus Time axis. Matlab was used to generate the plots shown.



Figure 13(b). Signal plots

The Figure 12 below shows the plot of raw and filtered signals in the same plots for comparison. plots of Digital

Audio Amplitude versus Time seconds.



Figure 13(c).Filtered signal plots

As seen in the in figure 13, the filtered signal is to be found within the desired band for analysis and is therefore

used to develop the algorithm that turns off the microwave.

Component Level Specifications.

The following are the design components specification;

Power

• Must supply 115V to Microwave

• 1-5V operating voltage of Reed Relay DIP switch

• 1-3V input DSB /DSK board



Microphone

Model SURE SM57

ü 40 – 15kHz Range

ü Open Circuit Voltage: -56.0 dBV/Pa* (1.6 mV)

ü 150 ohms Impedance (310 ohms actual)

Microcontroller board TMS320C6713 DSK

ü Excellent for multichannel and multifunction applications

ü Consists of 2-multichannel audio serial ports (AIC23 codec)

ü Easy communication with PC through Universal Serial Bus

ü Supports C/C++ compilers, IDEs, DSP/BIOS TM Kernels

Digital Switch Reed Relay DIP switch

Operating temperature 25oC

Operating Voltage 3.75v

Coil voltage 21V Type 5

Coil resistance min 450, max 550

Type 500.

GUI:

• Read in data from entered by the user

• Convert entered parameters to give desired output

• Store and display data as requires

• Needs to user friendly

• Acts as a source of choice validation or warning.

• Compatible with available hardware



Final design modifications

Many design decisions were modified from January 2008 to April 2008. Reasons for these changes varied in scope or

overall system effect, but all were deemed necessary by the design team. Among the last changes to be enforced was

using an amplifier to step up the voltage from the DSK board to the level that could operate the reed relay DIP switch.

The modifications can be seen in figure 12.

Figure 14. Modification block diagram

The bridge rectifier is used to smooth the AC ripples:- the amplifier raises the signal to 5 voltages. This is the

range of voltage that will turn on the dip switch to control the microwave.

Project Management

The following section includes the tasks, schedule, and budget of this budget. The goal of project management

is to constrain the project exactly to the weeks expected of a full semester.

Tasks

1. Project Definition: define all aspects of the project

a. Define Objectives - define the goals and objectives required

b. Define Constraints - define the constraints and limitations imposed

c. Conceptual Design - layout the conceptual design

d. Systems Charts - layout the necessary system charts

Bridge

RectifierAmplifier

Reed Relay DIP

switch



2. Proposal - refine the proposal

a. Actual Proposal - write the proposal

b. Project Timeline - plan and layout the project timeline

c. Work Breakdown Chart - plan and layout the personnel timeline

3. Subsystem Research - research and select optimum solutions

a. GUI - find the most efficient interface language and library

b. Data Structure - develop a program, fit to language

4. Interim Reporting - mid-project design review

a. Interim Communiqué - draft an interim notification letter

b. Interim Slideshow - present project progress and design choices

5. Final Design - integrate the complete design

a. Design Synthesis - write the program, compile on a computer

b. Design Testing - look for bugs, test speed and reliability

6. Final Report - draft and refine the final report

a. Actual Report - write the final report

b. Economic Analysis - run a cost analysis

c. Executive Summary - redefine the executive summary

MANAGEMENT

Assignment of duties and tasks to personnel, as outlined below:

Interfacing and system integration,-John Aruma;

Signal procession:- Tarnner Jones

Software development:- Khemmer Porter.



Among the assigned tasks are:

• Determining the amount of pop count sizes (i.e. count/ounce and also popping multiple

configurations).

• Signal analysis and counting using MatLab.

• Develop algorithm ranging from frequency to control algorithm.

• Determine the microcontroller PC, Micro-controller and Microwave interface.

• Develop Graphical User Interface (GUI ).

• Determining the microwave to be used

The Gantt chart schedule should be followed so that the project is completed within the time frame given.

Figure 14 shows Gantt chart, indicating different tasks and the outlined time - line of completion.



Materials and costs

Items Cost in USD

Microphone – Sure SM57 Already Owned

Microcontroller TMS320C6713

DSK

Issued

Popcorn 5

PC interface User’s Computer

Microwave 15

Reed Relay Switch 20

Man Hours 400 Coursework

Total 40

Figure 15. Table of costs



6. Conclusion

The main objective of this project is to create and implement algorithms that will prevent the overcooking of

popcorn. The algorithms will be realized using a micro-controller that will be interfaced with the microwave's

power control. All the objectives were met. The entire design was a success though the reed relay switch had to

be discarded and a higher power reed relay switch was used instead. The popped corn was tested by the

audience to verify the quality desired.



References:

1. Roizen, Michael, and Mehmet Oz. You:On Diet. 4. Prienceton:

2. http://recipes.howstuffworks.com/question255.htm

3. Sage, Andrew. Introduction to systems Engineering. III. New York: Wiley-interscience publication,

2000.

Attachments

The following are attachment:

Resume

Datasheets

Codes

Pictures


http://recipes.howstuffworks.com/question255.htm


John E. [email protected]

Permanent 4357643195

549 E 200 N

Logan, UT 84321

OBJECTIVE To become an employee and to make significant contributions that will lead to

company profitability and personal career growth.

EDUCATION Utah State University, Logan, UT

Bachelor of Science, Electrical Engineering, December 2008

Second Major- Mathematics.

Jomo Kenyatta University of Agr. & Technology, Nairobi, Kenya Associate Degree

(Diploma), Electronics Engineering, December 2001.

CERTIFICATIONS Cisco Certified Network Associate Instructor (CCNA)

RELATED

PROJECTS

Design of Water Gage using 8088 Micro-controller FIR,IIR & Adaptive filters

implemented using C++ & Results verified using Matlab

TECHNICAL

SKILLS

Web Development - HTML, XML, Java Script, JSP, VB Script, PHP Operating

Systems and Networking - Windows NT, Windows XP, Windows Vista, MS SQL

Server, Cisco IOS, Apache, Unix, Linux Software - Visual Studio. NET,MS Office,

Adobe Photo shop, Dreamweaver MX, Flash MX, Oracle Hardware - Basic PC

upgrades/repairs, Network cabling, connectivity troubleshooting, hard drive recoveries,

component level replacements Programming Skills - C++, ASP, Visual Basic, SQL,

MySQL, HTML, Java Script

RELATED

EXPERIENCE

Young Electric Sign Co., Logan UT Aug, 2006 - Nov.2007 Title: Data/Quality

Control Technician. Responsibilities: Testing and troubleshooting Electronic boards,

Calibrating and ensuring that they meet prescribed specifications and quality. Telkom

Kenya Ltd, Nairobi Kenya Dec,2003 - March, 2005 Title: Telecommunications

Technician Responsibilities: Testing, repair and troubleshooting Telecommunications

equipments e.g. Telephones, faxes, xDSL, Bridges, routers Holy Rosary College,

Nairobi Kenya Dec, 2001 - Dec, 2003 Title: Instructor and System Administrator.

Responsibilities: Teaching IT courses e.g. Java Script, Computer maintenance and

installations, Network design and setup and application programs. Administering

College Network

HONORS AND

AWARDS

The Player of the Year-Volleyball Jomo Kenyatta University(Fall 2001)

PROFESSIONAL

MEMBERSHIPS

Member, Institute of Electrical and Electronics Engineers - 2006 to present

Chairman, Computer society -IEEE USU Chapter.



POPCORN MACHINE - ece.usu.edu Final... · presented and final conclusive comments will be made including the accomplishments of the design ... A brief explanation of the ... Design

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