Transcript Slide 1

16.7 Million Color LED Light Fixture
Overview: The 16.7 Million Color LED Light Fixture
is based off of very high output LED technology and
the United States Institute for Theatre Technology
DMX512 protocol. The LED light fixture will
accurately track the control signals from a lighting
control board while operating at maximum
brightness and ensuring the LED’s operate
below their maximum junction temperature.
System Diagram
Christopher Yope
Jeffrey Knorr
Cost Analysis
Item
Temperature Sensors
Price ($)
Quantity
Blue LED
24
4
96
Red LED
8
4
32
Green LED
8
4
32
Power Supply
25
2
50
PIC
15
1
15
1
1
1
7.50
4
30
Connectors
10
1
10
Enclosure
15
2
30
Temperature Sensors
1
4
4
Heat sinks
2
12
24
20
1
20
Dip Switches
Dimmer Circuitry
5 Pin XLR
Connector
RS485 to TTL
Logic Convertor
Ambient
Temperature
Sensor
PIC
(Microcontroller)
The Microchip TC1047A
temperature sensor was used in
this design to measure the the LED
arrays’ temperature and the
enclosure (ambient) temperature.
Addressing
(Dip Switches)
Switching Power
Supply
OptoIsolator
OptoIsolator
OptoIsolator
Red
Dimmer
Green
Dimmer
Blue
Dimmer
Opto-Isolator/RS485
TOTAL (per fixture)
Total($)
344
DMX512 Algorithm
Red LED
Array
Green LED
Array
Blue LED
Array
Red
Temperature
Sensor
Green
Temperature
Sensor
Blue
Temperature
Sensor
Temperature Monitoring Algorithm
Capture LED Array &
Ambient Temperature
Within
Operating
Range?
User Interface
Determine Starting
DMX512 address
from DIP Switches
and set max channel
NO
YES
Apply Desired Output
Brightness Value
Scale desired output
brightness value to
maintain or reduce
array temperature
As the LED temperature increases,
the forward current carrying
capability of the LED decreases. To
compensate a simple algorithm was
incorporated into the design to
ensure that the LEDs would never
overheat.
Watch for falling edge
transition, then scan
for Break signal - Two
frames of ‘00’
Was
Break
found?
YES
Scan for Mark After
Break
Was MAB
found?
The user interface is the NSI
MC6300 professional stage
lighting board. Using the various
sliders and programmable
buttons, it is possible to create
any color, as well as strobe
colors, dim, full brightness, etc.
The board sends a DMX512
control signal to the LED light.
PIC18F458 Microcontroller
The Microchip PIC18F458 was
used as the microcontroller.
This was deemed a more
appropriate solution due to its
available specifications as well
as its cost.
NO
NO
YES
Scan for Null Start
Code - Signals
DMX512 Data follows
Dimming Circuit Schematics
Was
NULL
found?
The DMX512 Decode
algorithm is used to sort
through the incoming DMX
data from the lighting board
and determine which color to
vary based on that incoming
signal.
NO
YES
Read Dimmer Data
from DMX512 bus
and increment
channel counter
The circuits on the left are used to
provide the dimming and control
capability of the three LED arrays.
Power MOSFETs are used to provide
high speed full current switching
according to PWM signals for each
array.
Pictures of Primary Color Output
NO
Channel
counter >=
max
channel?
YES
Special thanks to:
•Dr. Czernikowski
•Dr. Reddy
•Darren Miles
•Harry Eisenbise
•CobraSound.com