TEAM “EPA”
ELECTRONIC PIN ART
Preliminary Design Review
Spring 2006
Jonathan Persinger
Jonathan Snyder
Henry Au-Yeung
Devon Dallmann
Khushboo Verma
Project Description
• An array of pins to display a variety of 3-D images
such as:
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–
–
–
–
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Pictures
Drawing
Text/Braille
Movies
Games
Integration with topography software (i.e. Google Earth)
Implementation
• Solenoid actuation
– PWM Control
– 256pin Resolution
• Software Algorithms and Programming
– Image Processing
– Embedded Interface communications
• Electronic Hardware
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Solenoid controller/selection
Compact Flash interface
External Memory
Power regulation
Power Requirements
• Each Solenoid requires a maximum of
400mA to set. (~1-2W)
• Maximum Current will occur at column
reset where 16 solenoids will be activated at
once => 16 x 0.400A x 5V=32watts
• Several voltage rails will be needed to run
the logic cores and solenoids.
System Overview
Goals
Fallback
•
•
•
•
Braille/Text
LEDs
Total Grid Reset
Image Processing
in MATLAB
• Hand Reset
• 4x4 Matrix
Goals
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16x16 pin matrix
4 Levels of pin
height
Static images
Single pic in
memory
One column reset
resolution
Joystick drawing
Extra
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Moving pictures
Joystick gaming
LCD/picture
menu
USB transceiver
DSP filters
Processor
TMS470R1A256
•32-bit ARM7TDMI core (industrial
applications)
•64 KB to 1MB flash memory
•12 KB static ram
•Clock speed up to 24 MHz
•14 High-resolution I/O channels
•I2C/SPI capable
CPLD Requirements
• Clock Standard bus
interface (IIC, SPI, etc.)
– SPI allows for full duplex
and any length instructions
• Counters and/or timers are
critical for pin height
resolutions.
– CPLDs offers consistent
delays.
• Pin for pin compatibility
with a CPLD with more
Function blocks
• 4 function blocks
• 21 GPIOs
• One function block must
have at least 16
Macrocells & 16 I/Os.
• +5v tolerance for
compatibility with
hardware logic and
drivers.
CPLD Design
uProc
4
ERROR W/ Inst#
SPI State machine
Increment Instruction
Instruction Packet
19
Decoder
Parity
8bit Inst#
Error Checking
3bit Z
4bit X
Timer
Decoder
2bit OP
Logic Gates (ANDs ORs etc.)
Inst# | Row 16b | inc Clmn | RST Clmn | PWM | HW-Busy
Driver Circuit
Objectives:
• Control of 256 individual solenoids
• Minimal part count per pin (cost control!)
• Must have the ability to switch polarity on
Solenoids
• EMI / ESD / EMF suppression & protection
• Critical Routing, isolation of current carrying
grounds and signal grounds
• Design in manual control and circuit isolation for
easier debugging.
Proof of
Concept:
Pin Selection
Proof of
Concept:
Solenoid Physics
N I SBmag
2 2
F
2
2L

L

R
L
R
Solenoid Physics
• Pulse duration controls height
• Trade offs:
larger N, less current needed, larger L,
larger time constant
Image Processing
• Process BMP, JPEG images
• Use MATLAB for image processing
– Obtain color matrix
– Algorithm to calculate height of the pin
– Obtain x and y location for each pixel along with the
height
• Store post-processed image to Compact flash
• Compile the image to MSP470 assembly
• Communicate between CPLD and Microprocessor
via Standard Peripheral/Bus Interface
• Read information from compact flash
– Determine memory mapping to locate pictures on card
CPLD Verilog
• State machine to fix PWM & frequency
• Translation of post-processed image to one
column at a time versus PWM Duration
• Miscellaneous Logic
– Pin reset
– Column select
– Multiplexing/Decoding
Division of Labor
• Henry—Power management; PCB layout;
mechanical design
• Khushboo—Image processing
• Jonathan S.—Solenoid control; System
integration
• Devon—Solenoid design; programming
• Jon P—Programming; PCB layout
Gantt Chart
Parts/Costs
Projected Costs
Item cost Total cost
PCB 1st and 2nd run
$100/run $200.00
Processor/Programmer
$200.00
Misc. Electronics
$100.00
Pin Rig
$200.00
Solenoids w/ pins
0.30/pin $300.00
Power Supply Materials
$100.00
Spartan III FPGA
$100.00
Misc. Hardware
$100.00
Connectors
$50.00
TOTAL
$1,350.00
Risks
• Processor/CPLD implementation
– Prior experience limited
– IC Communication problems
• SPI integration complexity
• Flash memory access (proprietary?)
• Cost/Availability
– Manufactured solenoids: Cost? Turn around? Many
parts are multiplied by 256 (runaway costs). Coil and
pin manufacture as of now is difficult.
• Coils
– High switched currents could cause re-triggering
– Pin height tolerance (all or nothing could result)
• Mechanical
– Tolerance of solenoid diameter and Rig spacing
– Longevity of moving parts
Marketability
• Visually impaired via. Braille coding
• Novelty item—place on mantel with wave
motion for relaxation
• USGS/Boy scout elevation profiles
• Automated tattooer
• Back massager
Questions & Comments
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