5/13/2011Andrew HobsonAndrew VitkusEvan GelfandSponsor: Dr. DeBartolo

PHASE

IIIP11003

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

CN1Ability to portray expression through learned ability

CN2Integration to PC through standard connections

CN3

Ability to differentiate individual key strike events, and associate them to corresponding sensor events in time.

CN4 Simple keyboard functionality

CN5 Must be reliable

CN6Establish a high level of device precision

CN7Design or consider other keyboard configurations for future teams

Engr. Spec.

#

Specification (description)

Unit of MeasureIdeal Value

ES1Keystroke has tactile Feel

Boolean Yes

ES2

Individual keys will be able to withstand at least 10N of force (2.25lbs)

Max force (N) 10

ES3Total component costs

Dollars ($) <1000

ES6Force Response Range

Force (N) 2.5

ES9Precision of force sensor

% error ±5%

ES17 Keyboard drivers -Origin

al

ES20 Type of PC Interface Type USB

ES21Paired Character Data

Boolean YesKey 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)

Outp

ut

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 Failures

Able 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?