1. Lucy Yan<lucytyan@bu.edu>, Jimmy Chau <jchau@bu.edu>, Thomas Little <tdcl@bu.edu>
Smart Light Undergraduate Research Program, Electrical and Computer Engineering, Boston University, Boston, MA
Embedded Control
Luminaire Structure
Controllable Lighting Future Improvements
Societal Benefits
Acknowledgements
This work is supported by the NSF under cooperative agreement
EEC-0812056 and by New York State under NYSTAR contract
C090145. Any opinions, findings, and conclusions or
recommendations expressed in this material are those of the
author(s) and do not necessarily reflect the views of the National
Science Foundation.
RGBA light with embedded controller
(delete this box unless applicable) IP relevant to this work is
available for licensing.
If interested, contact Dr. Silvia Mioc, miocs@rpi.edu
The RGBA luminaire is made of red, green,
blue and amber colored LEDs. This light is able
to change colors as well as dim or brighten.
Introduction
The ability to control lighting is an important
step in improving energy efficiency. If we can
provide customized lighting that offers exactly
what we need, when we need it, we will be able to
save large amounts of electricity, without
compromising our work or home environment.
Furthermore, by being able to change the color
and intensity of the light, we are able to provide
some health related benefits. Many people who
work in-doors do not get enough exposure to the
sun on a daily bases, affects vitamin D absorption
in the body. This problem can be fixed by more
exposure to right frequencies of blue light.
Another benefit of this, is mood improvement,
which can lead to a great increase in productivity.
Project Code ( A2.1.3 )
• Energy Sustainability
• Health, Safety, and well-being
• Increased Productivity
- Luminaire consists of 48 LEDs in total,
mounted evenly onto 8 thin PCB boards.
- Each board has a heat sink attached to the
back.
- Fiber glass outer frame provides structural
support and insulation.
- The Arduino is attached to the side of the frame
for easy access to ethernet cable and power
source plug-ins.
Through sending commands to the Arduino we are
able to dim, brighten or turn off completely, any color of
LED we wish to change. This is made possible by
changing the duty cycle, or on to off ratio, of the LEDs,
thereby changing the rate of flickering of the lights, also
known as PWM. This flickering doesn’t appear as a flicker
to the human eye, instead, it is perceived as dimming, or
brightening.
The Arduino is the embedded controller for the
RGBA luminaire. Basically, the Arduino waits for a
command from a connecting program (client), and
implements the command to an IP addressed set
of LED colors. Essentially the Arduino acts as a
server.
Here is a basic explanation of how we control the
luminaire through an Arduino:
- C/C++ is used to program the Arduino.
- Using the ethernet cable connected between the
Router and the Arduino, an IP address is assigned to the
Luminaire.
- The Arduino receives commands from the client in the
form: r###, through an external program such as
PUTTY.
- The first letter of the command represents color, the
following number ranges from 0 to 255 and represents
the brightness of that color of LEDs.
- The Arduino dims the LEDs through PWM.
Our motivation for this project was to provide a
versatile and IP-enabled color-controllable light
for future work. Also, this light was designed to
support one of Boston University’s senior design
teams’ projects. With this light, we are able to
further explore the control aspect of smart lighting.
- Customization: now that we have successfully
created the program to dim or brighten any
color at will, more customized settings are to
come.
- While the fiber glass provides strong structural
support, it is too heavy. The next luminaire will
be made of thinner strips of fiber glass, perhaps
even wood.
- Trace amounts of led can be found in a few
components used to build the lamp. Future
lamps will be led-free.
- Currently the luminaire has no light filters,
resulting in extremely bright light. With the right
lenses, color mixing abilities will be improved,
and the brightness will be less harsh.
A small lens that fits
over the small LED.
A possible addition to
future Luminaires.
With the 12 V power supply turned on, the Luminaire
draws roughly 68 W of power. The intensity of the light can
go from 0 (all LEDs turned off), to 2200 Lumens (all LEDs
turned on).
Wednesday, May 30, 2012