Todd Nelson
Ryan Straily
Overview
 Dimensions
 8x8x8, 512 LEDs total
 Individually Control each LED
 Microprocessor
 ATmega 328 (Arduino Uno)
 Persistence of Vision (POV)
 Power/Ground
 Minimal MCU control pins
 Shift Register
 Decoder
 Rapid Cycling
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Cube Construction
 Template for LED planes
 Grounding of planes
 Construction
 Connection to transistor
 Straightening of wire
 Soldering joints
 Connecting planes
together
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Circuit Board & Components
 Shift registers
 Input signal
 Clock
 Decoder
 Transistors
 Switches
 Resistors
 Current limiting
 Pull up/Pull down
Pull-up
resistors
3:8 Decoder
Shift Register (x8)
NPN transistor
Current Limiting Resistors
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Top Level Circuit Schematic
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Plane Schematic
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Row Schematic
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Arduino Uno
 Why we picked it
 Cost
 Ease of use (USB)
 ATmega 328 Microcontroller
 16 MHz Clock
 14 Digital I/O Pins
 6 Analog I/O Pins
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Code Flowchart
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Variables
 Global 8x8 char array - cube
 Stores values to be output to shift registers and
corresponding plane #
 Global int - current_layer
 Stores which layer the effect is currently on
 Global delay variable
 Scales delay times for functions to slow down effects
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Interrupts
 Output compare
 Scaled clock by 256
(6.25 KHz)
 Interrupt every 100
clock cycles
 Shifts out all 8 values in
8x8 array
 Ground selected plane
 Register C pin change
 Selects effects program
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Main Program
 Series of case statements to
select display effect
 Default is 0, which occurs
when reset button pressed
 After an effect program is
selected, it continuously
loops until another selection
made or reset occurs
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Effects
 Load the global array with
desired arrangement for a
plane
 Select corresponding plane
 1.6ms delay
 Delay time to allow for
viewing
 Sub-functions
 Coordinate System
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Summary
 512 LEDs
 85 feet of straightened wire
 Total cost per cube: $150
 Hours spent: 180 man hours
 Building: 140 hours
 Coding: 40 hours
 For 3 complete cubes
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Questions?
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 POV
 Control 512 LED’s individually with minimal number of
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MCU pins
Interrupt Routines and Hardware Flags
Timer System (clock scaling, output compare)
Power
PWM
Advanced C language concepts
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