Communication Device for Handicapped Kids

“Final Report”Project Dec 05 – 08

Client Heartland Area Education AgencySue

YoungFaculty Advisor Yao MaTeam Members: Brian Grove

Steve PetersAlex Leith

DISCLAIMER: This is a senior design project and all information contained within this document was written by students without any consultation from a professional engineer. To the best of our knowledge the content of this document is accurate; however, no guarantees are given to the validity of this document. All rights of this project are property of the senior design team and the client involved with this project. There should be no attempt to use this information without direct permission from the senior design team or the senior design course coordinator. If attempts are made to use this document without permission the parties involved will be subject to incur punishment to the fullest extent of the law.

Date November 1December 13, 2005

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Table of Content

List of Figures.................................................................................... i ii List of Tables....................................................................................

ivii List of Definitions..............................................................................

iv Executive Summary......................................................................... 1 Acknowledgement……………………………………………………….. 1Problem Statement.......................................................................... 1 Operating Environment.................................................................... 2 Intended Users and Uses................................................................ 2 Assumptions.................................................................................... 23 Limitations........................................................................................

3 Expected End Product and Other Deliverables................................ 34Project Approach and ResultsUsed................................................................................ 4 Functional RequirementsDesign Objectives....................................................................... 45 Financial Requirements...............Design Requirements Including................ Constraints............................... 56 Design Constraints...............Approach Considered and ..........One Sel..................ected……............................ 6

Technical Approach Considerations and Results....................... 6 Testing Approach Considerations............................................... 7 Recommendations Regarding Projects Future........................... 8Detailed Design.....................................................................................

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Microcontroller................................................................................... 8

Button Design.......................................................................................... 10 9 Power Supply Design......................................................................... 11 Changing Levels Design...................................................................... 11 Record Button and LED Design............................................................. 11 Other Considerations.................................................................. 12 Microphone Circuit................................................................................. 12 Speaker Circuit.......................................................................................... 132 One Button Control...................................................................................... 14 LED’s and Speed Control............................................................................. 145 Packaging.................................................................................................. 15 Software Algorithm to be Used.................................................................... 16 Memory...................................................................................................... 198 Image Editor..............................................................................................

20 Implementation Process Description………….…………………. 20 Testing of the End Product and its Results………..…….………. 201 End Results of Project……………………………….…………….. 201

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Resource Requirements..................................................................

201Schedules........................................................................................

236Project Evaluation……………………………………………………… 237Commercialization…………………………………………………….. 238Recommendations for Additional Work……………………………… 238Lessons Learned……………………………………………………….. 259Risk and Risk Management…………………………………………. 259Project Team Information.................................................................

3025Closing Summary.............................................................................

3126Referencessources........................................................................................

3327

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List of Figures

Figure 1: Main Schematic................................................................ 98Figure 2: Button Design................................................................... 10Figure 3: Microphone Circuit........................................................... 12Figure 4: Speaker Circuit................................................................. 13Figure 5: SPST Pushbutton............................................................. 14Figure 6: 3.5mm Plug and Jack....................................................... 14Figure 7: Top View of Device.......................................................... 15Figure 8: Side View of Device......................................................... 16Figure 9: Software Algorithm…………………………………………. 17Figure 10 Playback and Record Algorithm………………………….. 18

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Figure 911: Memory Chip Connections………………………………… 196Figure 1029: First Semester Schedule.................................................. 263Figure 1130: Revised First Semester Actual Schedule.…................................. 264Figure 1241: Second Semester Actual Schedule............................................. 274Figure 1352: Deliverable Schedule……………………………………... 274

List of Tables

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Table 1: Estimated Personal Effort Requirements........................................... 220Table 2: Revised Personal Effort Requirements............................. 221Table 3: Actual Personal Effort Requirements……………………… 221Table 43: Estimated Resource Requirements........................................................ 231Table 54: Revised Resource Requirements...................................... 232Table 6: Actual Resource Requirements……………………………. 242Table 75: Estimated Financial Requirements..................................................... 242Table 86: Revised Financial Requirements....................................... 253Table 9: Actual Financial Requirements…………………………….. 253

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List of Definitions

A/D converter – Accepts a continuous time signal in the from of an electrical voltage and produces a sequence of binary numbers

You may give more strict definitions of some of the terms below, by finding a digital commun. Text book. Some of them sound empirical and not so strict.Amplifiers – This device will increase the volume of the message going to the speaker

Analog signal – Analog is a continuous signal with no breaks in the waveform

Dielectric – A nonconductor of direct electric current

Digital signal – A dDigital signal is an analog signal that is sampled at different timesa specific interval so the signal is broken up into discrete samples

A/DD/A converter – Accepts a continuous time signal in the from of an electrical voltage and produces a sequence of binary numbersConverts the digital output from the microcontroller to an analog output

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Filters – Filters will only allow the desired frequency range to pass and block all other frequencies.

LED’s – Light emitting diodes that light up when voltage is applied across them

Level – Set ofPortion of memory that contains eight different recorded phrases

Memory – Refers Definesto how long a message can be stored into the microcontroller

Microcontroller – A device that acts as the brain behind the end product

Dielectric – A nonconductor of direct electric current

Pulse Wwidth Mmodulation – As the amplitude of the input signal increases or decreases, the output signals width increases or decreases with the change in amplitude

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Executive Summary

shall summarize the need for the project, the actual project activities, the final results, and recommendations for follow-on work. It shall contain a subsection for each of the items summarized.

Children with vocal disabilities, who may also have physical disabilities, require assistance with basic communication. Children being able to say simple phases, in order for others to understand what they desire, are essential in leading a normal life. The aim of this project is to create solutions to the problems faced by children with these disabilities.

Based on the needs and existing technology for children with these disabilities, the goal of this project became to create a device for these children that would be able to speak simple phases for them. Research was done on what would be needed in creating such a device. Different technologies were considered and selected based on device requirements that would effectively allow the user to operate the device. Designs using these technologies were created, tested, and debugged. Modifications were made to make the device function as planned.

Still in the implementation stage, the final modifications are being made. When finished, a prototype of the device will be builtd and tested by a child with the above mentioned disabilities and their caretaker. The device will have the ability to have multiple messages recorded by their caretaker. for playback,The child through the use of a multiple button touch pad, can then playback the messagesby a child as needed. The device will also have an accessory button, which is intended for children with physical disabilities. When in use, this button will take the place of the touch pad and be placed in a position where it will be easy to use.

Future additional work for this device could include a design force could include a computer program that can print pictures to go over the touch pad buttons. Also, an ergonomic case, and a battery charging circuit for the device could be designed.

Acknoledgement Acknowledgement

Our The team would like to thank our faculty advisor Dr. Yao Ma for his advice and ability to keep us the team on track (task). Also, our the team would like to thank Jason Boyd for working on the PCB layout and all his suggestions there. Finally our the team would like to thank Atmel for all the free components they provided.

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Problem Statement

This section will give a general overview of the project problem and a solution in which to solve it.

General Problem Statement

Some people with disabilities or handicaps have trouble speaking. Various communication devices have already been made to help handicapped people with such disabilities. The problem associated with this project is to create a similar portable device that will help handicapped children, who have a vocal disability, to , communicate with others. This device will have the capability to speak for kids who are limited in their ability. The speech for the device will be activated when a child presses a button with the desired picture.

General Solution Approach

To solve this problem a device equipped with a microphone will be able to record short phrases. These short phrases can then be played back at any time through speakers by pressing any of the buttons holding a recorded message. These buttons will have a picture representation and/ or text of what the child would like to say. Also, this device will be made fairly light weight so that even a small child will be able to carry it.

Operating Environment

The end product will need to be durable for the environment it will be inused. It will most more than likely be dropped a few times. In some instances, it could even be thrown. The users will carry the end product with them when they go to and from school. It should be able to withstand the weather, but it does not need to be waterproof. At school or home, the end product should be reliable. It needs to be able to keep up with the constant use it will receive from teachers, parents, and the kids.

Intended Users and Intended Uses

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The following will define intended users and uses of the product.

Intended Users

The intended users are children with vocal, learning, or physical disabilities and those people who take care of them.

Intended Uses

The device will be used to aid communication through a series of buttons that will play a recorded phrase or word. There must also be a way for caretakers to record custom words or phrases for later playback.

Assumptions

The assumptions for this end product are:

· It will only be used by one child at a time

· The child will be able to press the buttons

· The caretaker will have a computer to print the different pictures used when they reprogram the device

· The child can distinguish between the pictures

· The end product will be used in a home or learning environment

· The product will operate on rechargable batteries· · The product will be turned on and off by a power switch

· · The microcontroller and other features will use a sleep mode to conserve

energy when not in use.· · The end product will be programmable and will play back messages

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· · The product will be easy to use and understand by both child and

caretaker· · Assumptions

The assumptions for this end product are:

· It will only be used by one child at a time

· The child will be able to press the buttons

· The caretaker will have a computer to print the different pictures used when they reprogram the device

· The child can distinguish between the pictures

· The end product will be used in a home or learning environment

· The product will operate on rechargeable batteries

· The product will be turned on and off by a power switch

· The micro controller and other features will use a sleep mode to conserve energy when not in use.

· The end product will be programmable and will play back messages

· The product will be easy to use and understand by both child and caretaker

Limitations

The limitations for the end product are:

· The maximum size for the communication device will be 7” x 15” x 2”

· The maximum weight for the communication device will be 5 lbs

· Battery power must last for at least 16 hours under normal use

· Must be able to record messages for child to playback

· Rechargeable battery replacement must be easy

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· Each message will have a record time limit from one to five seconds

· Minimum number of messages is eight

· The cost of the product will not be more than $150 in materials

· Tests of the prototype will only be based on ease of setup and use

· The end product must be completed by December 2005

· The product must withstand being dropped from a height of 3-4 feet (ie.i.e.IE, a normal table)

Expected End Product and Other Deliverables

This component should contain a brief description of the end product and any other items that are ready for delivery or have been delivered to the client.

The end product will be a device with eight main buttons which can hold recorded messages that can be played back when pressed. The recorded messages are programmed in by the caretaker or parent of the child. A picture will be placed on top of each of the eight buttons to identify what message is stored for that button. Also a rotary switch will control what level the main buttons are on. There will be four levels that can hold eight messages each. Other deliverables include a user’s manual, and a single touch button.

An accessory to the device will be a single button. This button can plug into the end product and be placed near the child when they have limited range of motion and can not reach the eight main buttons easily. This single button will replace the main buttons by having LED’s light up one of the main buttons for a small period of time. Then it will move to the next button and so on. When the child recognizes the lit up button as the one they want, they can press the single button and it will playback the message. The speed at which the LED’s rotate around the buttons will be adjustable. A rotary switch on the side of the device will control the speed. The user’s manual will explain all the features of the device and how to operate it.

Project Approach and Results

The approach used will contain a description of requirements and considerations including:

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· Functional requirements· Design requirements including constraints· Approaches considered and one selected· Detailed Designdesign· Implementation process description· Testing of the end product and it’s results· End results of project

Functional Requirements

Functional requirements define exactly what the end product should and, likewise, should not do. Each functional requirement shall appear as an item in a list and be accompanied by a brief description.

The following functional requirements will be enforced for the development of a communication device for handicapped children if the group members can obtain the necessary resources to do so.

· Speak simple phrases – The communication device shall be able to speak simple phrases that are preprogrammed or recorded by pushing specific buttons. The simple phrases will be no longer than four or five seconds.

· Record simple phrases – The communication device shall be able to record phrases that can be played back when the appropriate button is pushed. The simple phrases will be no longer than four or five seconds.

· Volume control – The sound from the device will have an appropriate range of volume control.

· Design pictures for buttons – A template or software will be created to enable the user to print pictures for each button on the device.

· Eight main buttons – The eight main buttons will control the output of the device. When one of the buttons is pressed it will playback the appropriate message stored for that button. Each button will hold six messages; each message for a particular button will be stored on a different level. Therefore, a total of 48 messages can be stored in the device’s memory.

· One button control – This one button control will take the place of the eight buttons on the touch pad. This button will function as only one of the eight buttons at a time. LED’s will light up the active button, and when the child recognizes the active button as the one they want. They can press the one button control, and it will play the message stored on the active button. The LED’s will rotate around the buttons at different speeds

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controlled by a switch. If the child needs more time to react, the LED’s can be slowed down.

The following functional requirements will be enforced for the development of a communication device for handicapped children if the group members can obtain the necessary resources to do so.

· Speak simple phrases – The communication device shall be able to speak simple phrases that are preprogrammed or prerecorded by pushing specific buttons.

· Record simple phrases – The communication device shall be able to record phrases that can be played back when the appropriate button is pushed. The simple phrases will be no longer than four or five seconds.

· Volume control – The sound from the device will have an appropriate range of volume control. The device should be able to be heard from ten feet away comfortably. The device is not intended to be useds in ain loud environment.s

· Design pictures for buttons – A template or software will be created to enable the user to print pictures for each button on the device.

· Eight main buttons – The eight main buttons will control the output of the device. Each button will hold four messages; each message for a particular button will be stored on a differentone message per level. Therefore, a total of 32 messages can be stored in the device’s memory. When one of the buttons is pressed it will playback one message for the appropriatecurrently selected level for that button. The message will not be played more than once per button push.

· One button control – This one button control will take the place of the eight buttons on the touch pad. This button will function as only one of the eight buttons at a time.. LED’s will light up the eight mainactive buttons one at a time, and when the child recognizes the active button as the one they want,. t They can press the one button control, and it will play the message stored on the active button. The LED’s will rotate around the buttons at different speeds controlled by a switch. If the child needs more time to react, the LED’s can be slowed down. The rotation of the LED’s can not be stopped unless the one button control is not in use.

Design requirements including constraints

Design constraints should have been derived from the assumption and limitation lists, functional requirements, other project requirements, and other

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decisions made by the team members. Each design constraint shall appear as an item in a list and accompanied by a description.

The following design objectives will give an overview of the design blocks that had or need to be completed for a successful device.

· Eight main buttons design – An eight button array of touch sensing buttons have been designed to get user input. The user input will be used by the microcontroller software to output the correct message. There will also be a switch that will control three levels, which a caregiver will be able to change for the child. A total of 24 messages can be saved to memory. Eight buttons times six levels equals 24 messages.

· Sound input design – A circuit using a microphone as an input for the user’s voice has been designed. The user’s voice will be saved in memory by the microcontroller software.

· Sound output design – A circuit using a speaker to output the user’s voice has been designed.

· Microcontroller software design – A program for the microcontroller to control each function will need to be designed. The functions are explained later in the document

· One button control design – A circuit giving control to a single button, when plugged in, rather than the eight main buttons on the front panel will need to be designed. The one button control will also active an array of LEDs that will rotate around the eight main buttons showing which button is activated. The speed of the rotation of the LEDs will be controlled be the microcontroller software and an external switch.

· Power supply design – This circuit has yet to be designed. The power supply will power the device with rechargeable batteries. The user will have to recharge and replace the batteries every night.

· Software design to print pictures – If time permits, software will be developed in order for the users to change the pictures on the buttons. The users will have a template they can fill with different pictures and print that template out to insert over the buttons.

The following design requirementsobjectives will give an overview of the design blocks that had or need to be completed for a successful device.

· Eight main buttons design – An eight button array of touch sensing buttons have been designed to get user input. The user input will be used by the microcontroller software to output the correct message. There will also be a switch that will control four levels, which a caregiver will be able

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to change for the child. A total of 32 messages can be saved to memory. Eight buttons times four levels equals 32 messages.

· Sound input design – A circuit using a microphone as an input for the user’s phrasesvoice has been designed. The user’s phrasesvoice will be saved in memory by the microcontroller software.

· Sound output design – A circuit using a speaker to output the user’s phrasesvoice has been designed. It will take the pulse-width modulated output from the microcontroller and convert it back to the original waveform

· Microcontroller software design – A program for the microcontroller to control each function will need to be designed. The functions are explained later in the document

· One button control design – A circuit giving control to a single button, when plugged in, rather than the eight main buttons on the front panel has beenwill need to be designed. The one button control will also activatee an array of LED’s that will rotate around the eight main buttons, showing which button is activeated. The speed of the rotation of the LED’s will be controlled bye the microcontroller software and an external switch.

Software design to print pictures – Software will be developed in order for the users to change the pictures on the buttons. The users will have a template they can fill with different pictures and print that template out to insert over the buttons.

Approaches considered and one selected

Remember, approaches tell how the project will be done and not what the result will be. The approach component shall define: (1) each approach or technology considered, (2) the advantages and disadvantages of each approach or technology, (3) the selected approach or technology, and (4) the reason(s) for the particular selection.

The technology considerations for the communication device have been researched thoroughly and the most capable and proper components selected. Research has shown audio can be recorded and played back from the control unit with added memory. The control unit which is the microcontroller will need a program utility in order to program it. This is the heart of the design and most

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important component. These are some of the microcontrollers that were researched and a description ofdescribed why they would n’t not work.

The ISD5116 from Winbond Electronics Corporation was one of the microcontrollers considered. This microcontroller was however not chosen dueo to there not being enough I/O pins. The MSM6688 from OKI semiconductor was another microcontroller consideration; however, it also did not have enough I/O pins to supply the desired functionality.

The microcontroller the team ended up picking was Atmel’s ATmega8535L. This controller had enough pins for all the options needed and supplied a lot of documentation explaining how to use the controller for the purpose the team was looking for. Included in this documentation wasere a memory chip which the team decided to go withuse, a microphone circuit, and a speaker circuit.

The memory chip was originally an AT45DB161B which had only 16 Mbits of memory. Later the team found a similar chip with twice the memory from Atmel which was the AT45DB321C. This chip was selected because it allowed more space to hold the recorded messages.

The design has been broken up into blocks. Each block has a different aspect of the design. These blocks have been integrated together and an overall schematic has been finished. When the final design is complete the circuits will be tested using Pspice. Then the team will build the circuits on bread boards in the lab where they will be tested again.

The input circuit, consisting of a microphone and filter, connects to the microcontroller. The team found the circuit on Atmel’s data sheet and made sure it would work for the design. The circuit needed gain of around zero dB and cutoff frequency of 4000 Hz. Also, the output circuit had to follow the same criteria. This circuit, which is a sixth- order Butterworth filter and speaker, will play back the message. Here the team had to design the output circuit from scratch and use Pspice to make sure it would work.

When all circuits pass the desired tests tThe PCB board will has been drawn up and Jason Boyd haswill taken care of making the PCB layout for the team. Then the teamwill soldered the components onto the PCB board and the circuit has beenwill again be tested to make sure it works properly. When all components of the board pass the tests, the client will be contacted and allowed to test the device. If any changes need to be made, this will be done and the end product will be completed.

Other approaches considered were using push buttons instead of touch buttons using a sensor chip. The advantage for using push buttons would have made the circuit design easier, but the cost and reliability was not as good as a touch button. The team went with the touch button because of the cost and reliability

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issues. There were a lot of different buttons researched which can be found at this web site: http://www.nkkswitches.com/switchcategory.asp?S3=3. The touch button works by detecting a change in capacitance as you the user touches the area designated as the button. There really is notn’t a button just a grid like surface that is connected to the sensor chip. When you the user touches the area the useryou changes the capacitance and the chip detects this. Then the chip outputs the button the useryou touched through an 8:3 line encoder to the microcontroller.

An encoder was used to cut down on the number of microcontroller pins needed for the buttons. Encoders are pretty common so the team went with the first encoder they found. The only requirement was to convert the eight button output to a three line input. The team had to put an array of nand gates to negate the input to the encoder.

The software considerations were done using the AassemblySM language. This was changed over to C later on, as it was discovered that there were libraries available from Atmel that did many of the things wethe team wasere trying to doattemping.

At first, the AVRStudio4 provided by Atmel was used. This failed due toon several levels, such as the lack of a suitable simulation, and the lack of header files containing chip specifications for the compiler.

The next software suite used was WinAVR, a freeware suite based around the avr-gcc compiler. This also lacked a simulation suite.

The final software used in the development was VMLab by VMWare. It had a very powerful simulation suite, and the avr-gcc compiler was able to to be used to produce the code.

Detailed design

The detailed design shall include a complete set of drawings, completely labeled, that correctly reflect the final version of the end product. Often during implementation and testing, changes are made to the original design. All of those changes shall be incorporated into this part of the report. A complete list of parts, their source, and estimated cost shall be included. Any other significant factors shall also be documented.

Supporting calculations, simulations, graphs, charts, photographs, etc. should also be included.

The following section displays detailed schematics and descriptions of the design for the communication device., up to this point. Some designs are still being

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developed and all designs shown or described may be subject to change; however, the designs shown should give insight to the general overview of how the device will be implemented.The designs are completed as much as possible at this time. ; Hhowever, some changes may be made during the final debugging stage.

Microcontroller

The microcontroller is the heart of the design, everything hinges around it. The schematic may be hard to read but it will give a general idea of the layoutof what is going on (see Figure 1 on next page). -> (Give a larger picture if possible).

Figure 1: Main Schematic

The microcontroller is an ATmega8535L controller from Atmel Corporation. The specifications and cost are:

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· 8-bit controller · 32 general purpose registers· 8000 bytes in system programmable memory· 8-channel 10-bit ADC· Cost is $5.70

The I/O pins are divided up into four ports. Port A is for the analog input and is the only port connected to the ADC. The ADC will sample the incoming signal at 8000 Hz. Port A will control the microphone circuit, speed selector, and input from touch sensor chips. Ports B, C, and D are all the same. Port B is used for the data flash memory. Port C is used for the LED’s, and Port D will control the external interrupts, 43 level selector, 3.5 mm stereo jack, record button, and speaker circuit. There will be an 8 MHz resonator to control the clock and since the ADC will be used, there will need to be a low-pass filter connected to pins AREF and AVCC.

To minimize the power consumption of the microcontroller these steps will be implemented in the software, when possible:

1. Enable sleep mode 2. Disable ADC in sleep mode3. Disable analog comparator

Button Design

The following description describes the button circuit, the components used, and the reasons for choosing components. The button circuit is shown on next page (see Figure 2). (larger picture would be better).

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Figure 2: Button Design

The button design contains two QT140 touch sensor integrated circuit chips. These touch sensors have the ability to sense touch through any dielectric and cost $2.89 a piece. The touch sensors will allow the eight buttons on the front panel to be flat by using a single layer of a dielectric, which has not been chosen yet.. The flat surface is desired to make sliding a sheet of paper across the buttons physically easier, which would be difficult for any general push button. Also, the touch sensors will be more robust and last longer because there are no moving parts as apposed to a push button device, which has pressure limitations while pushing the buttons and will eventually fail to work. Another advantage to the touch sensor ICs is that the total weight for all eight buttons will be less than the total weight of eight separate push buttons.

The two touch sensor IC chips work together through the sync pin to guard against two buttons being simultaneously pressed. The touch sensor will pull the appropriate output pin high when a button has been pushed. The eight output pins from the touch sensor will be input to an 8-to-3 encoder which will then be input to the microcontroller. Also, when any button is pushed an enable pin, acting as the external interrupt for the eight buttons, connected to the microcontroller will be pulled high.

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Power Supply Design

The power supply design, consisting of six AAA rechargeable batteries, will power the device. Three AAA batteries will be connected in series and then connected in parallel to anotherthe other three AAA batteries in series. This will help with battery life and output 3.6 volts to the circuit.

Changing Levels Design

The following description describes how the levels for the eight buttons on the front panel are changed.

The levels are controlled by the user with a rotary switch which will be limited to fourthree settings for each of the fourthree levels. When the binaryrotary switch is set to a particular level it will set the appropriate pin or pins on the microcontroller high., These pins arewhich will be either pin PD0 and, PD1, or PD5. When the pin goes high the microcontroller will know which level the user wants and output those messages stored under that level. The rotary switch was donated by Square D.

Record Button and LED Design

Thise following description explainsdescribes the record button and LED circuit and the components used.

A small push button also donated by Square D will be used to allow the user to record a new message when needed. TAlso, for the user there will be an LED that lights up to let the user know when the device is recording and when it is not. The user will hold down the record button and one of the eight main buttons associated with the message.

Microphone Circuit

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The microphone circuit is made up of a microphone, low-pass filter, and amplifier. The microphone is how the user will input messages to store in the memory, which will be discussed later. Since the microcontroller will sample the message at 8 KHz, the design of the low-pass filter was essential to make the 3 dB cutoff frequency at 4 KHz. The 3 dB cutoff means that for a low-pass filter all frequencies below 4 kHz are allowed to pass while the frequencies above 4 KHz are blocked or cutoff. The amplifier increases the gain of the circuit (See Figure 3).

0

P A 0

R 3

1 0 k

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V C C

C 1

1 u

1 2

R 5

1 0 k2

1

V C C

0

V C C

C 2

4 . 7 n

1

2

0

R 2

1 k

21

R 4

1 0 k2

1

R 6

1 2 k

21R 1

1 k2

1

M I C R O P H O N E

U 1 A

L M 3 2 4

1

3

2

411

O U T

+

-

V+

V-

Figure 3: Microphone Circuit by Atmel

The amplifier is a simple inverting amplifier. The gain is set with R2 and R3 (gain = R3/R2). R1 is used to power the microphone and C1 blocks any DC component to the amplifier. R6 and C2 form a simple first order low- pass filter. Also, R6 protects the amplifier from any damage if the output is short circuited. The output of the circuit will be connected to the microcontroller at pin PA0.

Speaker Circuit

To playback the messages, a speaker will be used along with a 6 th order Butterworth filter, four unary gain amplifiers, and a 5k potentiometer to control the volume (see Figure 4 on next page).

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Figure 4: Speaker Circuit

The speaker circuit will be connected to pin PD4 on the microcontroller. The circuit above is broken up into three parts. The first three op amps are the 6th- oorder Butterworth filter, and then R13 and C6 is a simple low-pass filter. Finally, the last four op amps are unary gain amplifiers to protect the circuit from feedback and boost the current to the speaker. The filters 3 dB cutoff frequency arefrequency is designed to be 4 KHz. Resistors R1, R2, R5, R6, R9, R10, which are set toare 33 KΩ’s, and capacitors C1, C2, C3, C4, C5, C7, are set to 1are 1 nF, make this possible (See equation below).

4 KHz ≈ 1/(/ (2*π*33,000*1*10^-9)

R13 and C6 is a low-pass filter that makes the cutoff a little steeper for better quality. R14 is a potentiometer that can be adjusted from 0 to 5 KΩKOhms (use math symbol here). As the resistance is increased the power supplied to the speaker will decrease. This will cause the volume to decrease. An 8 ΩOhm speaker will output the message.

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One Button Control

This button, donated by Square D, is different then the other eight buttons. It will be separate from the device so children with limited mobility can still use it. This button will be a simple button that is very large and easy to operate (see Figure 5).

Figure 5: SPST Pushbutton Switchwww.radioshack.com

The button will be connected to the device by a 3.5 mm stereo plug and jack (see Figure 6).

Figure 6: 3.5mm Plug and Jackwww.connect-tech-products.com

The plug is divided up into three parts. If you look at the plug in Figure 6 there are three parts to the piece that goes into the jack. There is the tip of the plug, the next piece is the ring which is in between the two black lines, and finally there is the sleeve.

The jack has contacts inside it to detect the tip and ring. The tip contact in the jack will be connected to the microcontroller through pin PD6. The ring contact will be connected through pin PD7. When the button is plugged into the jack, the

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microcontroller will detect the tip of the plug and disable the other eight buttons on the device. When the button is pushed, the ring will be pulled high and the microcontroller will detect this and play the appropriate message. There will be LED’s that flash around the buttons and this is how the device will know which message to play, which will be explained next. The plug and Jack cost $2.34

LED’s and Speed Control

The LED’s are light emitting diodes that light up when a voltage is place across them. These LED’s where donated also. Each button on the device will have LED’s by them which will light up for the child only when the one button control is connected. When the button with the desired message is lit up, they can push the one button control, and play the message associated with that button. The LED’s will move in such a way as to only light up one button at time. They will go around in a circle and light up each button. Also, since each child will not be able to move at the same speed, the LED’s will be able to have the speed at which they flash rotate around each the buttons sped up or slowed down,, through an eight 10-speed selector. This will be a switch on the side of the device that the caretaker can adjust for the child.

Packaging

The packaging of the device will be a plastic box that costs $16.47. The front panel of the device will be 7 X 12 inches as shown below (see Figure 7). The front panel will contain the eight main buttons along with an on/off switch and a vent for the speaker sound to be heard. The side panel displayed, on the next page, (see Figure 8) will be located at the top of the front panel. The side panel will be 1 X 12 inches and contain the charger, and contain the one button control inputs, the record button, the level selector, and the LED speed control rotary switches.

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Figure 7: Top View of Device

Figure 8: Side View of Device

Software Algorithm to be Used

Memory is divided up into 24 blocks, one for each message. The first character will be the length of the sounds to be played back, and the rest of the block will be ‘frames’ of sound that are stored. Each frame is the level of the sound wave at the time that the frame was taken. During development and testing, the team will determine the significance of this number; each increment might be anywhere from one to a thousand frames.

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To record, the microcontroller will take the analogue level from the microphone a set number of times per second, and record each ‘frame’ to the next spot in the block for the sound that is recording. After the recording is finished, it will save how long the recording button was held down, up to five seconds.

To playback, the microcontroller will first read in the length of the recording from memory. Then, it will take that many frames from the memory, and output them to the speaker through the pulse width modulator one at a time. The PWM emits a pulse ever X seconds, and the width of the pulse is equal to X * ( OCR1B / 0xFF). The pulses will go into a capacitor in the external circuit, which will 'smooth out' the pulses into an output waveform.

These are the general algorithms that will be used for this project. More will be added, and the current ones will be revised as the project continues to take shape.Software Algorithm to be Used

Memory is divided up into 32 blocks, one for each message. The first character will be the length of the sounds to be played back, and the rest of the block will be ‘frames’ of sound that are stored. Each frame is the level of the sound wave at the time that the frame was taken. During development and testing, the team will determine the significance of this number; each increment might be anywhere from one to a thousand frames.

To record, the microcontroller will sampletake the analooguge voltage level from the microphone at 8 KHz set number of times per second, and record each ‘frame’ to the next spot in the block for the sound that is recording. After the recording is finished, it will save how long the recording button was held down, up to five seconds.

To playback, the microcontroller will first read in the length of the recording from memory. Then, it will take that many frames from the memory, and output them to the speaker through the pulse width modulator (PWM) one at a time. The PWM emits a square wave pulse at a frequency of 33khz, and the width of the pulse is equal to (1/33,000) * ( OCR1B / 0xFF), where OCR1B is the 'level' of the sine wave at that frame. The pulses will go into a capacitor in the external circuit, which will charge to a higher voltage as the pulses get longer, and charge to a less high frequency as the pulses get narrower. A low- pass filter in the circuit will then eliminate the high frequency PWM wave from the signal, and the original sound wave will be restored.

These are the general algorithms that will be used for this project (See Figure 9 on next page). More will be added, and the current ones will be revised as the project continues to take shape.

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First, the general loop:

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Figure 9 Software AlgorithmsHere is a detail of the playback and recording algorithms provided by Atmel. These have been modified slightly to fit theour implementation:

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Figure 10 playback and record algorithms

Essentially, these deal with the details of the implementation, such as waiting for a buffer overflow, or the transfer of pages of memory to / from the flash chip.

Memory

The memory is DataFlash(R) produced and donated by Atmel. The team has chosen this memory package because it is an extremely versatile package, capable of handling a wide variety of bus speeds, and having a very simple interface. The team also found documentation on the company website detailing how we tocan properly integrate this chip with the microcontroller and the rest of the circuit. The exact model recommended for use was the AT45DB321C (See

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Figure 11), which has 32 Megabits of storage space. The pins that the team will be using on the memory chip are as follows:are:

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Figure 911 Memory chip connections

RES – The reset pin. This resets the memory.

RDY – Ready. If this is high, the device is ready for the next bit of data. If it is low, then it is busy.

WP – Write protect. If this is held low, then the first 256 pages are protected and can't be written to.

CS – Chip select. When low, the chip will accept an instruction. When high, the chip will not accept an opcode.

SI – Serial input

SO – Serial output

SCK – Serial clock

The SCK will be tied to the same clock signal in use by the microcontroller so that it can send and receive data in serial with the memory unit. The rest of the pins will be tied to normal input / output pins of the microcontroller.

Image Editor

The team will, include a simple image editor that will create the button images that will be inserted into the device. The team has not yet determined the scope of this image editor.

On the more complex end, there will be a Visual Basic program that a user can load up to eight images into, and it will allow the user to crop these images to the appropriate size, and then combine them appropriately into an image that can be printed out.

On the simplistic side, iIt will be a document template that the user can load into Microsoft Word. The user will then be able to manually select their images, and Microsoft Word will be able to output a document with the button images laid out appropriately.

Implementation process description

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This shall include descriptions of any problems encountered and how the problems were overcome. Suggestions for how the implementation process might have been improved shall also be included.

Maybe it’d be better to included problems encountered and solved. For example, the volume was too weak in the original design, with changes of components to make it right. Some problems in software and some corrections made.Once the design was completed, the design was implemented with a bottom up approach. Individual components (such as the speaker circuit, and the microphone circuit) were built on a breadboard, and then tested in the labs to ensure correct volume on the output and the input waveform was of the appropriate magnitude. The software was simulated as much as possible using VMLab IDE. Once all components were simulated, they were integrated into the final circuit, and the final circuit was tested to ensure that it all worked.Once the design was completed, the design was implemented with a bottom- up approach. Individual components (such as the speaker circuit, and the microphone circuit) were built on a breadboard, and then tested in the labs to ensure correct volume on the output and the input waveform was of the appropriate magnitude. The software was at first implemented using aAssemblySM with the AVRStudio 4 by Atmel. This was proving to be very tedious, as aAssemblySM is very hard to develop on, and AVRStudio was so bad that not even Atmel used itnot user friendly. Deficiencies included the lack of a suitable simulation, and the lack of header files containing chip specifications for the compiler.

Libraries were discovered that contained many of the functions that the team wanted to implement. They were used at first in WinAVR, and then in VMLab. VMLab was able to successfully simulate the output onff the chip, and to simulate a waveform being fed into the ADC.

The speaker circuit originally outputted a signal that was too weak for the speaker. When the circuit was tested on a breadboard, the volume was too low and the sound could barely be heard. To solve this problem the team had to add another amplifier to the speaker circuit, which would increase the gain, and also they added unity gain amplifiers to increase the current to the speaker as well. When this was done the volume was loud enough and could be heard from ten feet away.

Testing of the end product and it’s results

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In documenting the testing activities, the following should be considered. How and where the testing was performed? Exactly what was tested? How was the testing accuracy determined? Who did the testing and how was it verified? In general, at least some part of the testing should have been conducted by non-members of the project team.

The end product will need to be tested in order to make sure it meets the client’s needs. This will include battery life and functionality of all the different components. The battery will be tested by operating the device under highest load conditions to make sure it will last at least the desired 16 hours.

Each component, like the one- control buttonbutton control and eight main buttons, will also be tested along with all the others. The one control buttonbutton control and the eight main buttons will be tested in a similar manner. When a button is pressed, the functionality will be verified by verifying that the correct message wasbeing played. The volume control will be tested by playing the same message at different volume levels to verify the change in volume. These components need to pass all tests measuring the accuracy and durability of the device. When the team is satisfied the client will be contacted for further evaluation.

The final end product testing will consist of user interaction with the prototype communication device and any computer software written. The user testing the communication device and the user setting up the device will be a student and their teacher, respectively, provided by Heartland Area Education Agency. The criteria of the prototype testing will consist of the observation of usability displayed by the users.

The end product will need to be tested in order to make sure it meets the client’s needs. This will include battery life and functionality of all the different components. The battery will be tested by operating the device under highest load conditions to make sure it will last at least the desired 16 hours.

Each component like the one control button and eight main buttons will also be tested along with all the others. The one control button and the eight main buttons will be tested in a similar manner. When a button is pressed, the functionality will be verified by verifying that the correct message was played. The volume control will be tested by playing the same message at different volume levels to verify the change in volume. These components need to pass all tests measuring the accuracy and durability of the device. When the team is satisfied the client will be contacted.

The final end product testing will consist of user interaction with the prototype communication device and any computer software written. The user testing the communication device and the user setting up the device will be a student and their teacher, respectively, provided by Heartland Area Education Agency. The

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criteria of the prototype testing will consist of the observation of usability displayed by the users.

End results of the project

Any other significant or important items not documented elsewhere in the final report shall be covered in this subsection. For example, significant accomplishments or research activities not covered elsewhere shall be covered here. The final status (state) of each major component of the end product might be summarized here. Remember, failures are often as important as, or even more important than, successes. The device is in the prototype implementation and testing stage at this time. The PCB is being created and built and the software is getting written to program the device. When this stage is finished the device will be ready for to demonstratione to the client. Hopefully the client will be pleased and the device will operate the way it was intended to. The project at this time is under budget, on schedule, and the design requirements have been met.

Resource Requirements

The resources required are broken up into three parts: personal effort requirements, resource requirements, and financial requirements. Personal effort requirements are made up of the hours it has taken or will approximately take to complete each task defined in the statement of work. Each team member’s estimated hours is are in Table 1 on next pagebelow; the revised hours up through Task 3 are shown in Table 2 on the next page. Also, table 3 has the actual hours up through task 4.

· Task 1 – Problem Definition· Task 2 – Identify Technology and Selection· Task 3 – Design· Task 4 – Prototype Implementation and Testing· Task 5 – Demonstration

Table 1: Estimated Personal Effort RequirementsPersonal Name Task 1 Task 2 Task 3 Task 4 Task 5 TotalsSteve Peters 7 25 32 82 14 160Brian Grove   12 35 37 82 15 181Alex Leith   10 40 40 85 16 191

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  Totals 29 100 109 249 45 532

Table 2: Revised Personal Effort RequirementsPersonal Name Task 1 Task 2 Task 3 Task 4 Task 5 TotalsSteve Peters 5 23.5 6 82 14 130.5Brian Grove   8 31.5 7.5 82 15 144Alex Leith   7.5 32.5 16 85 16 157  Totals 20.5 87.5 29.5 249 45 431.5

Table 3: Actual Personal Effort RequirementsPersonal Name Task 1 Task 2 Task 3 Task 4 Task 5 Totals

Steve Peters 5 23.5 6 98.559 71413307.5

Brian Grove   8 31.5 7.5130.57

2 7.5151851

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Alex Leith   7.5 32.5 16138.58

1 816202.5153

  Totals 20.5 87.5 29.5359.52

12 22.545520.5394.5

Resource requirements are made up of the cost for parts and services that will be needed in order to complete the project. These costs for the required resources may change due to different components found from research or from acquiring free samples (see Table 4 on next page3). Distributors will be considered in the next phase of the design project. The revised resource requirements are shown on next page (see Table 54). The actual resource requirements are found on Table 6 on the next page 24.

Table 4: Estimated Resource Requirements

Item  Team Hours

Other Hours Cost

Parts and Materials:        Microcontroller   0 0 $20.00Electronic Components   0 0 $55.00Batteries   0 0 $10.00

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Poster   25 0 $10.00  Subtotal 25 0 $95.00Services:      Printed Circuit Board   20 118 $40.00Packaging   30 0 $25.00Print Poster   0 48 $10.00  Subtotal 50 166 $75.00           Totals 75 166 $170.00

Table 5: Revised Resource Requirements

Item  Team Hours

Other Hours Cost

Parts and Materials:        Microcontroller   0 0 $36.00Electronic Components   0 0 $52.00Batteries   0 0 $8.00Poster   20 0 $10.00  Subtotal 20 0 $106.00Services:      Printed Circuit Board   20 118 $40.00Packaging   30 0 $25.00Print Poster   0 48 $10.00  Subtotal 50 166 $75.00           Totals 75 166 $181.00

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Table 6: Actual Resource Requirements

Item  Team Hours

Other Hours Cost

Parts and Materials:        Microcontroller   0 0 DonatedElectronic Components   0 0 $8980.00Batteries   0 0 $8.00Poster   20 0 $10.00

  Subtotal 20 0$10798.0

0Services:      Printed Circuit Board   20 118 $4033.00Packaging   30 0 $250.00Print Poster   0 48 Free  Subtotal 50 166 $6553.00         

  Totals 75 166$16360.0

0

Financial requirements are all of the costs from labor, parts, and services combined. This will show the total cost of the project. The cost for the required components may change (see Table 57). The revised financial requirements are shown below (see Table 68 on next page). However, the actual financial requirements are found in Table 9 on the next page.

Table 7: Estimated Financial Requirements

Item  W/O Labor

With Labor

Parts and Materials:      Microcontroller $20.00 $20.00Electronic Components $55.00 $55.00Batteries $10.00 $10.00Poster $10.00 $10.00

Subtotal $95.00 $95.00Services:      Printed Circuit Board $40.00 $40.00Packaging $25.00 $25.00Print Poster $10.00 $10.00

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  Subtotal $75.00 $75.00Labor at $10.50 per Hour:      Steve Peters $1680.00Brian Grove   $1900.50Alex Leith   $2005.50  Subtotal $5586.00  Total $170.00 $5756.00

Table 8: Revised Financial Requirements

Item  W/O Labor

With Labor

Parts and Materials:      Microcontroller $36.00 $36.00Electronic Components $52.00 $52.00Batteries $8.00 $8.00Poster $10.00 $10.00

Subtotal $106.00 $106.00Services:      Printed Circuit Board $40.00 $40.00Packaging $25.00 $25.00Print Poster $10.00 $10.00  Subtotal $75.00 $75.00Labor at $10.50 per Hour:      Steve Peters $1370.25Brian Grove   $1512.00Alex Leith   $1648.50  Subtotal $4530.75  Total $181.00 $4711.75

Table 9: Actual Financial Requirements

Item  W/O Labor

With Labor

Parts and Materials:      

MicrocontrollerDonated$

5.70$Donated

5.70Electronic Components $8090.00 $80890.00

Batteries$8.00Don

ated$8.00Don

atedPoster $010.00 $010.00

Subtotal$95.79810

7.000$98107.0

095.70Services:      Printed Circuit Board $4033.00 $4033.00

Packaging$250.003.

15$250.003.

15Print Poster Free Free  Subtotal $653.0046 $6553.04

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.15 6.150Labor at $10.50 per Hour:      

Steve Peters$1396.50

128.75

Brian Grove  $1942.50

407.00

Alex Leith  $2126.251606.50

  Subtotal$5465.254142.25

  Total$1630.001

41.85$4302.255607.10

Schedules

This is the schedule for the first semester. The blue lines refer to main tasks, while the green lines indicate subtasks. The black line is for summer break (see Figure 912).

Figure 1029: First Semester Schedule

This is the revised first semester schedule (see Figure 1013)

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Figure 1130: First Semester Actual Schedule Revised

This is the second semester schedule (see Figure 1114).

Figure 1241: Second Semester Actual Schedule

This is the deliverable schedule for both semesters (see Figure 1215).

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Figure 1352: Deliverable Schedule

Project evaluation

This section will explain the different milestones and progress that has been made. The explanation shall include whether or not each milestone was greatly exceeded, exceeded, fully met, partially met, not met, or not attempted. An explanation shall be provided of the evaluation process. This explanation shall include a description of how the individual milestone evaluations are combined into a total project evaluation and what that evaluation result is.

Milestones:· Research – fully met· Identify possible technologies – fully met· Product design – fully met· Build testable Mmodules (ie. Speaker circuit) – partially met (what is the

definition of Build Modules here? for future senior design use? )· Program microcontrollerdevice – partially met· Demonstration – not attemptedpartially metnot attempted ( programming the MC. Does that fall within this category?)

The team started out with researching possible technologies that could be implemented in the communication device. Each technology was gone over, discussed to figure out the pros and cons, and then decided upon. This took a lot of time but the milestone was fully met and the team moved on to the design process.

Designing the device was made easier by documentation provided by Atmel who supplied us with the desired microcontroller the team selected. There were some bugs to work out of the design like the speaker circuit, but through research these obstacles were overcome.

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Next the team moved into building the modules and testing them. Here some unforeseen challenges came up like providing the speaker with enough power. The modules that could be tested worked and programming the device will be the next step. The team needs to build the PCB board and solder components on it in order to test the software that will run the microcontroller. From there somethere, the device will continue to be debuggeding and finally demonstrating the devicedemonstrated to the client and review panel. The last two milestones weren’t attempted because we haven’t reached that stage at this time.

Commercialization

At a minimum, it shall include estimates of the following items: (1) what might be the cost to produce the product, (2) what might be the street selling price of the product, and (3) what might be the potential market for the product.

Although commercialization will not be a consideration of the end product, if commercialization were a consideration, the total cost to produce the communication device would depend on the component prices only. The parts or instruments needed that would only be a one time expense will not be included in the total cost of production because as the number of devices produced becomes large, the cost of the one time expenses per device will go to zero(?) (better give a more accurate estimation of the whole hardware cost).

Adding all the component prices, the cost of product per device would be @@@. Comparing this device to other devices on the market, the selling price of the device will be @@@ which is about @@@% of the production cost.

The market for this device will be anyone with vocal or vocal and physical disabilities (more comments, make it more convincing).Although commercialization will not be a consideration of the end product, if commercialization were a consideration, the total cost to produce the communication device would depend on the component prices and labor costs. The parts or instruments needed that are only a one time expense will not be included in the total cost of production because as the number of devices produced becomes large, the cost of the one time expenses per device will be negligible.

Taking into account all the component prices and the cost of labor, the cost of product per device is estimated to be $80.00. Comparing this device to other devices on the market, the selling price of the device will be $160.00, which is about 200% of the production cost.

The market for this device will be anyone with vocal or vocal and physical disabilities. If an individual has trouble communicating with other people and

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they can’t use sign language, writing, or other forms of communication, then this device will be of use to that individual.

Recommendations for additional work

Recommendations shall be more than just a list of items and shall include a description of each item and specific reason(s) for the recommendation. If the recommendations include any modifications, enhancements or additions, the reasons for the changes shall be included.

Additional work could include features like a battery charging circuit, more ergonomic case, LCD touch screen, or wireless communication. The device as of now just uses rechargeable batteries that need to be taken out and recharged in a separate device. If a charging circuit was designed to charge the batteries without taking them out of the device that would make it much more convenient for the user.

A more ergonomic case could include a handle for easy caring capabilities or designed in such a way to be placed on any surface where it could sit securely and not move around. Image Editor

The team will, time permitting, include a simple image editor that will create the button images that will be inserted into the device. The team has not yet determined the scope of this image editor.

On the more complex end, there will be a Visual Basic program that a user can load up to eight images into, and it will allow the user to crop these images to the appropriate size, and then combine them appropriately into an image that can be printed out.

On the simplistic side, it will be a document template that the user can load into Microsoft Word. The user will then be able to manually select their images, and Microsoft Word will be able to output a document with the button images laid out appropriately.

Finally, the device could be connected up to a computer through a wireless communication network and enabled with a LCD touch screen. With this feature there would be no need for the image editor because pictures could be downloaded to the device over the wireless connection and displayed on the touch screen. Also the device could be programmed using a computer instead of having to hold down the record button and speaking into a microphone to program the messages.

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Lessons learned

The things that went well included the communication and the ability to stay on schedule displayed by the team. One thing that did not go well was ordering parts the first time. The parts took longer than expected to come in and as a result held back other tasks that needed to be done.

The technical knowledge gained was during the design of the device. Knowledge and experience, of how to implement circuit designs and software, was gained. The non-technical knowledge gained was during the research of existing technology in order to design the device. Existing technology was discovered and their uses were learned.

Looking back, if the project could be done over again, the only thing that would be done differently would be in the ordering of parts so that the group would not be delayed and the progress of the project would be smoother.The things that went well included the communication and the ability to stay on schedule displayed by the team. One thing that did not go well was ordering parts the first time. The parts took longer than expected to come in and as a result held back other tasks that needed to be done.

The technical knowledge gained was during the design of the device. Knowledge and experience, , of how to implement circuit designs and software,, was gained. The non-technical knowledge gained was during the research of existing technology in order to design the device. Existing technology was discovered and their uses were learned.

Looking back, if the project could be done over again, the only thing that would be done differently would be in the ordering of parts so that the group would not be delayed and the progress of the project would be smoother.

Risk and risk management

1. Anticipated potential risks and planned management (required).2. Anticipated risks encountered and success in management (required).3. Unanticipated risks encountered, attempts to manage and success

(required). 4. Resultant changes in risk management made because of encountered

unanticipated risks (required).

Anticipated Potential risks:

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· Data loss – Data was backed up to the software developer's secondary laptop often.

· Loss of Team Member(s) – extensive documentation was done so that other team members could take up the slack should one member disappearLosses of tTeam mMember(s) – extensive documentation was done so that other team members could take up the slack should one member disappear.

· Damage to sensitive equipment – redundant chips werewas acquired, and all other parts are obtainable from Radio Shack.

Anticipated risks encountered and success in management:

· Primary software development laptop died. Was able to recover critical documents from the backup laptop.

· One team member dropped early in the first semester. We were The team was forcedforced to move some of the software to the “Future work” page.

· No chips have been damaged, but one microphone was destroyed with a soldering iron. A replacement was easily at hand.

Unanticipated risks encountered,encountered, attempts to manage, and success:

The compiler we that was used (avr-gcc) wasn't correctly compiling theour code, so the software developer had to trick the compiler in order to get it to work correctly.

Resultant changes in risk management made because of encountered

unanticipatedunanticipated risks.

Software was more fully tested, and output assembly was examined to ensure the compiling was correct.

Project Team Information

The personnel involved with this design project isare:

Client Information

Heartland Area Education Agency (AEA 11)

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Sue Young, Assistive Technology Consultant6900 NE 14th Street – Suite 26Ankeny IA 50021Phone # (515) 289-4575Fax # (515) 289-4579sue_young@aea11.k12.ia.us

Faculty Advisor

Yao Ma3107 Coover(515) 294-8382mayao@iastate.edu

Team Members

Brian GroveElectrical Engineering10440 Wilson Werkman(515) 572-3008bgrove@iastate.edu

Steve PetersComputer Engineering7312 Fredrickson Ct.smpeters@iastate.edu

Alex LeithElectrical Engineering1304 Wallace KilbourneAmes, IA 50013Cell # (515) 290-8836aleith@iastate.edu

Closing Summary

One way to accomplish this is to briefly summarize the problem, the approach used, and the resultant solution.

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The team hopes that through this communication device life will be made much easier for handicapped children. They should be able to communicate with their caretakers in way that they couldn’t could not before. Some children have disabilities which keep them from communicating very easily, or at all, with the outside world. This problem is difficult to handle but can be made better. Creating a device that can record a person’s voice phrases to be played back later, for a child that does not have the ability to speak, will allow them to live a better life.

Maybe below you can give more examples for actual technical problems encountered and solved.Approaching this problem was difficult but with the help of Sue Young the team came up with a product that would really make a difference. The team researched a lots of components and found a microcontroller that was able to apply all the functionality the device called for required. Next From there piecing together the schematicthe schematic needed to be designed and testing the circuit had some obstacles that needed to be overcome,. like Like redesigning the speaker circuit because the one Atmel provided didn’t work. Also, the speaker was no’t getting enough current to output the message at an acceptable volume. Integrating the microcontroller and the hardware circuits caused another problem. The team had to make sure that the PWM signal outputted by the controller would work with the speaker circuit design. Finally, and building a prototype, along with and finishing writingthe software to run the microcontroller were all difficult tasks in them selves.

However, the team did a real good job and the communication device should provide all the features a handicapped child would need. Some features include storing messages that can be played back by pushing a button. When a child with limited mobility can no’t press the main buttons, a single button can operate the device. LED’s will light up the main buttons and when the desired button is selected the child presses the single button to play the message. Also, there will be a speed control for the LED’s and a switch to control the different levels for the device. With all things considered the ability to communicate is one of the most basic and essential needs. This device should provide that need at an affordable cost to the user.

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References

1. AVR335: Digital Sound Recorder with AVR and Serial Data Flash. 4 April 2005<http://www.atmel.com/dyn/resources/prod_documents/doc1456.pdf>

2. Digi-Key Corporation. 4 April 2005<http://www.digikey.com>

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