Real Time Embedded SystemFinger Finger Revolution

EE4214

Inspiration

Real Time Arcade Machine

Real Time Game Application

Finger-Finger Revolution•Rhythm-and-Hand Gesture Gaming

Platform ▫Supports Gesture Detection▫Plays Music▫Provides Visual Display

Brief System Overview

ControllerMemory

PWM LCD IR Hardware Drivers

Hardware•IR Sensors – captures hand gestures•LCD - displays timer, scoring and moves•Sound buzzer – plays PWM pitch tones

Voltage Regulator•Regulates incoming

7.5 vdc to 5 vdc•1A Max current limit•Capacitors to remove noise

in power source

IR Circuit•Converts IR’s analog signal

to digital•Transistor acts as switch

Finger Detection Logic level at output

Detected (no IR light received)

5v or ‘High’

Not Detected (IR light received)

0v or ‘Low’

Buzzer High Pass Filter•Logic ‘Low’ produces 0.3v at

PWM0 output•HPF used to remove this offset•Cutoff Frequency formula•fc= 15.9Khz•Audible range 20 to 20kHz

LCD Connections•RT1602•2 rows x 16 columns•LCD using 4-bit data mode

Flow Chart

Task Criticality Firm•Game Timer•Music Playback•LCD Updating

Soft•IR Input Sensing•Score Updating

Task SchedulingTask Period

(Ti)Computational Time (Ci)

Priority (P)

Utilization (Ui)

LCD 250ms 10ms 1 0.04

IR sensor 250ms 10ms 2 0.04

CalScore 250ms 20ms 3 0.08

UpdateMove

250ms 20ms 4 0.08

UpdateTime 1000ms 20ms 5 0.08

PWM 500ms 20ms 6 0.04

Task Utilization Analysis• Processor Utilization Factor:

UP = = 0.300

Up ≤ 1 (schedulable)

• Utilization Least Upper Bound (1973, Liu and Layland):- Ulub

RM = n(21/2 - 1) = 0.735

- Case, for large n, n → ∞: Ulub → ln 2 ≈ 0.693

Since Up ≤Ulub in both cases, schedulable with RMA.

• Hyperbolic Bound (2000, Bini et al.):

• Hence the 6 periodic tasks are schedulable with RMA.

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LCD

IR Sensor

Scoring

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Overall Timing

Timing Diagram

Update time

PWM sound

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Update move 250m

s750ms

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Timing Diagram Cont’

State Transition Diagram

Data Flow Diagram

Data Flow Diagram Cont’

Data Flow Diagram Cont’

Data Flow Diagram Cont’

Inter Process CommunicationMailbox with Semaphore

LCD IR Sensors

ControllerFIFO1 FIFO2

Calculate Score

Socket PWM

Possible Improvement•More time •More help support•Multi-Player mode

Lesson Learnt“What works on paper may not be feasible

in implementing it…”