Proposal
Speech Recognition Calculator (SRC)
ECE4007 Senior Design Project
Section L02, Calculator Team
Alfredo Herrera
John Holmes
Alex Kee
Josh Liang
Submitted
September 17, 2007
Table of Contents
1
INTRODUCTION..................................................................................................... 1
1.1
OBJECTIVE ........................................................................................................... 1
1.2
MOTIVATION........................................................................................................ 1
1.3
BACKGROUND ...................................................................................................... 1
2
PROJECT DESCRIPTION AND GOALS ............................................................ 2
3
TECHNICAL SPECIFICATIONS ......................................................................... 3
4
DESIGN APPROACH AND DETAILS ................................................................. 4
4.1
DESIGN APPROACH .............................................................................................. 5
4.2
CODES AND STANDARDS ...................................................................................... 6
4.3
CONSTRAINTS, ALTERNATIVES, AND TRADEOFFS ................................................ 7
5
SCHEDULE, TASKS, AND MILESTONES ......................................................... 7
6
PROJECT DEMONSTRATION............................................................................. 8
7
MARKETING AND COST ANALYSIS ................................................................ 9
7.1
MARKETING ANALYSIS ........................................................................................ 9
7.2
COST ANALYSIS ................................................................................................... 9
8
SUMMARY ............................................................................................................... 9
9
REFERENCES........................................................................................................ 10
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Executive Summary
Contained in this proposal is a description of the design and manufacturing of a speech
recognition calculator targeted towards population with disabilities. These users need a
tool to aid in mathematical and arithmetic computation that places physical interaction at
a minimum. Currently, there exists no calculator that successfully meets the needs of
these users.
The SRC (Speech Recognition Calculator) features were chosen in order to facilitate the
operation for these users. Completion and satisfaction of these features is the ultimate
goal of this design. This proposed design will produce a stand alone and intuitive
calculator suitable for all disability types.
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Speech Recognition Calculator (SRC)
1 Introduction
1.1 Objective
People with disabilities need a tool to aid in mathematical and arithmetic computation
that places physical interaction at a minimum. The Speech Recognition Calculator (SRC)
aims to be an all-in-one solution for people of all disabilities – limited movement, limited
vision, and limited hearing.
1.2 Motivation
Typically, calculators require heavy physical interaction in the form of pressing buttons
that makes use of very precise motor skills. Such skills could be a deterrent for customers
with limited movement and limited vision. Currently, the market for disability-oriented
calculators has few choices. In addition, existing products fail to adequately fulfill the
needs of the population with disabilities – namely the need for hands-free operation. Most
existing products focus solely on limited vision customers, yet still rely on physical
movement.
1.3 Background
To take an example, Orbit Research offers the Orion Talking Calculator for low-vision
customers [1]. The model features speech feedback on actions (button presses and
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computation). However, the calculator still requires the need to physically interface with
the device.
This proposal offers a design that will produce a hands-free, accurate, and intuitive
calculator which will satisfy the needs of its users. The design will be centered on a
central microprocessor that will handle most of the computation. Several components
will interface with this processor to provide input and output capabilities: a microphone, a
speech recognition chip, a LCD display, and a speaker.
2 Project Description and Goals
Customers with disabilities need a hands-free, speech-recognition device in order to
perform basic arithmetic. Currently, the market for disability-oriented calculators offers
few options for this clientele, which include users with limited vision, limited hearing,
and limited physical movement. The SRC aims to fill this void by providing features that
cater to all disabilities, such as:
•
Limited Vision
o LCD screen that is easy to read and can print large characters
•
Limited hearing
o High volume in order to hear the feedback voice
•
Limited mobility
o Hands-free operation
•
General
o Intuitive operation
o Clear and audible feedback speech
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Furthermore, the calculator must perform all the functions of a standard calculator and
meet the need of a diverse speaking population. In order to meet the need of the
customers, the calculator will feature:
•
Basic arithmetic operations
•
Bilingual support (Spanish and English)
•
Speech recognition capable
•
Speech feedback
•
Optional remote operation via internet
•
Speaker independence
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3 Technical Specifications
Table 1. Design Specification
Aspects of Designs
Design Specification
Electrical Specifications
Voltage Requirement
5V
Operating Current Requirement TBD
Audio Specifications
Microphone Frequency/ dB
20 Hz to 20 kHz (-44dB)
Speaker driver
8 ohm, 300mW
Display Specifications
LCD Display type
STN, YG, positive, transflective
[2]
Accuracy Specification
Probability of missed word
1 out 100 words
Dimension Specification
Weight
TBD
Size
TBD
Environmental Specifications
Operating Temperature
0°C to 30°C
Storage Temperature
-10°C to 40°C
Network Specification
Connectivity
RJ-45 Ethernet cable (100Mbps)
The voltage requirement is dictated by the analog speech recognition circuitry [3].
Current requirements will be determined once the circuit is built. However, for
comparison, Sensory Incorporated’s RSC-464 voice-recognition microprocessor requires
12mA at 3V [4].
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The calculator will operate with different volumes and strive to achieve speaker
independence. To this end, a microphone capable of capturing frequencies in a range
from 20Hz to 20 kHz is necessary to capture all pitches of voice from speakers. In
addition, it is estimated that a microphone sensitivity of -44 dB is required to have a
system gain of -49 dB to pick up all ranges of voice volumes [4]. These specifications
ensure both the speak independence and clear speech feedback from the system.
In order to be accurate, the SRC will have to achieve one missed word for every 100
spoken words. In addition, a noise tolerance threshold must be determined once the
system is operational.
The calculator will have the capability for remote connections via the Internet. The
connection will be made via an Ethernet cable connection rated at a 100 Mbps. A
standard browser interface will be used to connect and interact with the calculator.
For proper device functioning, operation must take place within 0°C to 30°C. For the
device memory not to be damaged/corrupted, storage temperature should be within the 10°C to 40°C range.
4 Design Approach and Details
4.1 Design Approach
Figure 1 shows a block diagram schematic of the entire SRC system. Voice signal input
is provided via a microphone, converted by the analog SR (speech recognition) chip into
digital signals, and then fed into the microcontroller for actual computation and display.
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Microphone
(Input)
Analog Speech
Recognition Chip
Microcontroller
LCD Display
Text-to-Speech
Chip
Figure 1. Block diagram showcasing speech recognition calculator.
Table 2 provides the parts that have been pre-selected to build the SRC, based on their
compatibility.
Table 2. Selected Parts for SRC
Parts
Function
HM2007 by Hualon
Recognize and analyze the user’s
voice
Basic Stamp by Parallax
Microcontroller chip that compute
the arithmetic operation.
LCD by Parallax
Will display the answer visually
4.2 Codes and Standards
Since the product is to be marketed to the general public, the IEEE Code of Ethics is
applicable [5]. Thus, all IEEE ethics codes will be followed, with emphasis on those that
concern public safety.
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Furthermore, Section 508 of the Department of Justice guidelines [6] establishes certain
criteria that must be met by the device when used by the U.S. government (i.e. public
schools), a likely primary customer of the SRC.
According to Section 508 of the U.S Guide to Disability Rights Laws, no person can be
discriminated because of their physical disabilities [6]. Moreover, this law also implies
that agencies must have some kind of accommodation to make technology and
electronics equally accessible to people with disabilities. The SRC is one step in the right
direction to help federal agencies provide people with disabilities equal access and
opportunities to perform to their fullest.
4.3 Constraints, Alternatives, and Tradeoffs
Initially, the RSC-464 microchip by Sensory Inc. was considered to accomplish both the
speech processing and the arithmetic calculations in a single chip. However, it was
decided not to use the VR Stamp because it was expensive, heavily software-oriented,
and required additional assembling.
Another alternative investigated was to build a speech recognition circuit using a Texas
Instruments DSP processor. This route was decided against due to its cost, timeconsuming building, and heavy reliance on C programming.
5 Schedule, Tasks, and Milestones
Tasks which have been met at this time comprise of:
1- formation of product concept
2- ordering of parts for product construction
3- technical review papers written for vital components
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Tasks which must be taken on from this point forward are specified in the Gantt chart in
Figure 2.
Figure 2. Gantt chart showing proposed tasks.
5.1 Meeting Schedule
Weekly status meetings will be held on Fridays in the Klaus Advanced Computing
Building until project completion. Lab hours for product building and testing will be
scheduled as appropriate.
6 Project Demonstration
In order to demonstrate the capabilities of the calculator, access will be opened to a wide
sample of consumers. The consumer group will verify the calculator functions by
performing tasks that test each of the fundamental features. First, a simple simulation will
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be performed to test the MCU math accuracy. Second, a simulation will be performed to
test speaker independence. Simulated bilingual capabilities will be tested along with the
ability to recognize voices belonging to different individuals. Lastly, the speech
recognition ability will be tested through direct visual-audio validation between speaker
input and LCD display output.
The demonstration will also showcase the limits of operation for the calculator. For
example, one speaker will be asked to speak at a specified words-per-minute rate in order
to verify speech recognition accuracy at high speeds.
7 Marketing and Cost Analysis
7.1 Marketing Analysis
The SRC calculator is an all-in-one, disability-friendly calculator that introduces a handsfree, speech recognition and speech feedback system. The calculator can also be used to
remotely tutor users. Since production options on the market is currently very limited,
the cost of the calculator should not impede market success. The unit cost of an SRC
calculator will be around $250.
7.2 Cost Analysis
Tables outlining the details of cost analysis may be found in Appendix A.
8 Summary
The SRC provides a solution for customers that need to provide equal-access
opportunities to population with disabilities. Federal codes such as Section 508 make this
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a requirement for Federal agencies. The SRC meets such codes in a cost-effective manner
by providing an all-in-one solution that incorporates limited vision, limited hearing, and
limited movement users. Product verification testing at the end of development will
incorporate real users to test each of the mentioned groups as well as additional calculator
features.
9 References
[1] Orion Talking Calculator, Orbit Research, Wilmington, DE, 1999.
[2] Parallax Inc. Technical Staff, Parallax Serial LCD, Parallax, Inc., v.2.0, 2006.
[3] Images Scientific Instruments Inc., “How to Build a Speech Recognition Circuit,”
Images Scientific Instruments Inc. [Online]. Available:
http://www.imagesco.com/articles/hm2007/SpeechRecognitionTutorial01.html.
[Accessed: Sept. 15, 2007].
[4] VR Stamp With Serial EEPROM Speech Recognition Module Data Sheet, Sensory
Inc., Sunnyvale, CA, 2005.
[5] Institute of Electrical and Electronics Engineers, Inc., IEEE Code of Ethics.
Piscataway NJ: IEEE, 2003. Available:
http://www.ieee.org/portal/cms_docs/about/CoE_poster.pdf. [Accessed Sept 15, 2005]
[6] United States Department of Justice, “Section 508: The Road to Accessibility,”
United States Department of Justice, Section 508 (29 U.S.C. ‘ 794d). [Online].
Available: http://www.section508.gov/index.cfm. [Accessed: Sept. 15, 2007].
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Appendix A
Table A1. SRC PRICE CALCULATIONS
SRC PRICE CALCULATIONS
Fringe Benefits
Overhead
Sales Expense
30% of labor
120% of materials, labor & fringe
10% of selling price
Table A2. Labor Cost
Labor Cost
Engineer 1 (100 hrs x $26)
Engineer 2
Engineer 3
Engineer 4
Total Labor Cost
$2,600
$2,600
$2,600
$2,600
$10,400
Table A3. Development Cost
Development Cost
Parts
Labor
Fringe Benefits, % of Labor
Subtotal
Overhead, % of Matl, Labor & Fringe
$231
$10,400
$3,120
$13,751
$16,501
Total
$44,003
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Table A4. Bill of Materials for 1 Unit
Bill of Materials for 1 Unit
HM2007
8K x 8 SRAM
74LS373
7448 x 2
LCD Display
BASIC STAMP II
Keypad
Protoboard
Microphone
Wires, Resistors, and Capacitors
Parallax Internet Netburner Kit
Total
$10
$8.85
$0.80
$1.50
$20
$49
$10
$15
$5
$12
$99
$231
Table A5. Determination of Selling Price
Determination of Selling Price
Based on:
Parts Cost
Assembly Labor
Testing Labor
Total Labor
Fringe Benefits, % of Labor
Subtotal
Overhead, % of Matl, Labor & Fringe
Subtotal, Input Costs
Sales Expense
Amortized Development Costs
Subtotal, All Costs
Profit
Selling Price
Net Profit
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100,000 units
$231
$30
$10
$40
$12
$283
$340
$120
$29
$0
$149
136
$285
$13,600,000
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