5/13/2011Andrew HobsonAndrew VitkusEvan GelfandSponsor: Dr. DeBartolo
PHASE IIIP1100
3
Dynamic Keyboard Phase II
Dynamic Keyboard Phase III
Overview Customer Needs and Engineering Specifications Concept Selection System Architecture Mechanical/ Electrical Design Overview Testing Results Current State Successes and Failures Next Step What would We Change? Questions?
Agenda
Design and manufacture a PC keyboard that will sense key pressure
Utilize Dynamic Keyboard, Phase I, and Dynamic Keyboard Phase II recommendations
Hand off Dynamic Keyboard, Phase III, so that Phase IV will create software applications
Dynamic Keyboard Overview
Dynamic Keyboard Phase III
Customer Needs and Engineering Specifications
Customer
Need #Description
CN1 Ability to portray expression through learned ability
CN2 Integration to PC through standard connections
CN3Ability to differentiate individual key strike events, and associate them to corresponding sensor events in time.
CN4 Simple keyboard functionalityCN5 Must be reliableCN6 Establish a high level of device
precision
CN7Design or consider other keyboard configurations for future teams
Engr. Spec.
# Specification (description) Unit of Measure Ideal
Value
ES1 Keystroke has tactile Feel Boolean Yes
ES2Individual keys will be able to withstand at least 10N of force (2.25lbs)
Max force (N) 10
ES3 Total component costs Dollars ($) <1000
ES6 Force Response Range Force (N) 2.5
ES9 Precision of force sensor % error ±5%
ES17 Keyboard drivers - Original
ES20 Type of PC Interface Type USB
ES21 Paired Character Data Boolean Yes
Key Customer Needs Key Engineering Specifications
Concept Selection
Concept Selection from MSDI
System Architecture Overview
User Input Original Keys
Feedback Mechanism
Original Keyboard
Membrane
Sensor Martix
Internal Frame
Mechanical Stop
(threashold)
Micro Controller PCSensor
Controller USB Hub
Hardware CasingModified Keyboard
System
Original Controllor
System Architecture Block Diagram
Assembly Overview
Modified Bottom Casing
Fabricated Wedge
Custom PCB with Force Sensors
Modified Top Casing
4-40 x 1” Screws
Fabricated Band
Dynamic Keyboard Exploded View
Chose SpecResearch K-558/U keyboard for aesthetics, cost, and space for electronics
Used standard domes (not foam)
Reversible construction
Used standard size fasteners (4-40 x 1” SHCS)
Mechanical Design Overview
SpecResearch K-558/U
Electrical Design Overview
Single PCB design USB interface 86 Pressure Sensors (Force Sense Resistor) Implemented Arduino Nano MCU 2 RGB-LED provide feedback Sends Key-Pressure paired data Sampling frequency up to 60 Hz Keyboard hardware interface API Integrated with original keyboard hardware
Arduino Nano MCU
Mechanical Specifications: weight, dimensions, cable length allexceeded customer specifications
Electrical Specifications: signal delay, sample rate, power required, controller resolution, operating frequency met or exceeded customer specifications
Testing Results Overview
Custom Made Pressure Testing Fixture
Pressure Testing Results
50 100 150 200 250 300 350 400 450 5000
20
40
60
80
100
120
140
160
180
Pressure Sensor Data
Qtp\zbLeft ShiftNumber Pad 1Number Pad 9
Weight (g)
Out
put
Valu
e
Graph of Key Pressure Testing Results
Keyboard is built and operational
Dual functionality Standard Keyboard Dynamic Keyboard
LEDs provide visual feedback for users
Outputs Key-Pressure paired data
Functional Keyboard software suite
Current State
Assembled Dynamic Keyboard Phase III
Successes and Failures
SolidWorks Top View of Pressure Sensors on PCB
Successes FailuresAble to communicate between SolidWorks and PCB Artist
Wedge had to be re-designed
Custom PCB/ keyboard matrix alignments
Keyboard selection
Positive feedback at ImagineRIT
F10, F11 buttons do not function
Only one “spin” of PCB required
Custom PCB and FSRs took up majority of budget
Extra FSRs left over Mechanical Noise
Under budget Dome placement
Normalize sensor values Further develop controller API Develop software applications that utilize the key-
pressure data. Applications: text size and color change, shortcuts
to programs, enhanced passwords, shorthand writing, autocorrect, gaming, ergonomics
Next Step
Proposed Text Application
Design smarter sensor matrix PCB configuration
Use brand name keyboard with single dome pad
Enhanced mechanical support Use a microcontroller with faster ADC Further develop software Perform more rigorous testing
What Would We Change?
Dome Pad
Questions?