Download Report on the conception, design, prototype, and evaluation of a

Report on the conception, design,
prototype, and evaluation of a Light
Sensitive Dimmer that minimizes
power consumption
by Cody Coleman, Tshiamo Lechina, and Tatiana Mamaliga
Abstract
In order to minimize the consumption of electrical energy used for lighting, we proposed to
conceive, design, prototype, and evaluate a Light Sensitive Dimmer that senses the brightness of
natural light and varies the intensity of the light bulbs used to light the rooms. Our team met
multiple times to brainstorm and discuss several ideas to come up with a final design, which is
using a light sensor and a dimmer switch to regulate the amount of power that light bulbs use. Our
Light Sensitive Dimmer is able to sense the brightness of natural light outside the windows and
adjust the amount of energy used to power the bulbs. These requirements are addressed by the
dimmer switch that varies the intensity of the light bulbs based on the input that it receives from the
light sensor located by the window. There's no considerable risk to the user of our device; the only
risk that we anticipate related to our device is for one to electrocute him/herself if touching the
circuit included in our device. However, the risk is minimal, as our circuit is safely insulated with
electrical tape. When mass produced, such switches can contribute to the world economy by
saving money on energy used for lighting.
Introduction
A Light Sensitive Dimmer is of significant importance to the world. It is commonly observed that a
lot of energy is wasted at times when the lights are turned on during the day, even when there is
enough daylight pouring through the windows. However, most of electricity comes from
nonrenewable sources of energy (i.e. coal), and it is costly, which affects both the environment and
the economy. To solve this problem, this project was to conserve the energy that is often wasted by
the unnecessary use of lights during the day. In addition to the requirement that it sense the
brightness of natural light outside the windows and adjust the amount of energy used to power the
bulbs, this device also
satisfies the following requirements:
●It does not expose anyone to undue hazards;
●It does not occupy a large area in the room;
●It does not interfere with the main electrical circuit of the building so as to damage it;
●It is optional to use;
●It is for individual-room use;
●The product has a small ecological footprint, both in terms of the materials used to construct the
product and the labor required to produce the product.
Background
Energy Model
The light sensor by the window estimates the amount of natural sunlight that comes into the room,
and sends an impulse to the dimmer switch, making it adjust how bright the bulbs should be. We
analyzed the amount of energy lost in a hypothetical situation that the lights are left on from 7am to
5pm in ESG as follows:
about one hundred of 100 W Fluorescent light bulbs in ESG
Estimated Energy used by the bulbs in one day:
Energy=Power *Time
=100 W*10 hrs*3600 sec=3.6 MJ for one bulb
for 100 bulbs:
3.6 MJ*100=360 MJ
over one semester:
12 weeks * 5 days * 360 MJ=2.16*10^10 J
Cost of this energy:
Amount of electricity used in one day costs 100*100 W*10 hrs=100kWhrs
Over one semester: 12 weeks * 5 days * 100kWhrs=6000kWhrs
Cost of electricity in Massachusetts: 16.6 cent per kWhr
in one semester the cost of that electricity would be: 6000kWhrs*$.166 = $998
~ $1000
Safety Analysis
When constructing a device to conserve electrical energy used to light rooms, as required by our
project, we considered several factors. The device prevents exposure to undue hazards. We safely
insulated it with electrical tape to prevent electrocution. It does not interfere with the main
electrical circuit of the building so as to damage it because it will only be connected to the light
source of one room. It has a small ecological footprint, both in terms of the materials used to
construct the product and the labor required to design the product, as it consists of a small circuit
involving several wires and a few simple electrical components. We regarded these safety
requirements with highest priority when considering the Light Sensitive Dimmer, and we took
them into strong account when designing our device.
Aesthetics and ergonomics
For our design the Aesthetics and ergonomics requirement was not a concern. The Light Sensitive
Dimmer does not occupy a large area in the room and consists of a compact circuit.
Materials and labor costs
The materials that we used for the Light Sensitive Dimmer as well as the corresponding
prices are:
-light sensor – photo diode --$19.51 (including shipment)
-dimmer switch—$57.52 (including shipment)
-wiring—$4.00
total cost: about $81
Methods
Design overview:
The Light Sensitive Dimmer consists of a light sensor and a dimmer switch connected together
with wiring and programming tools. The light sensor detects the amount of brightness that the
room receives from natural lighting and sends an input to the programmed dimmer switch. The
dimmer switch then associates the data with a specified intensity and gives out a corresponding
amount of energy to the bulbs.
Design Selection
There were a number of ideas that we came up with while thinking of a device to make that will
save energy. Each of us contributed to picking the one design that we chose to proceed with by
ranking the following factors about each design as illustrated on table 1 below. Since the main
objective is to reduce energy footprint, the factor, “will reduce a lot of energy” was ranked out of a
maximum of 6 points, while the other factors were ranked out of 3 points. By popular vote, the
switch that adjusts intensity of light depending on the brightness of sunlight turned out to be the
design we picked for our project.
Possible
Designs
Team
Technical
member slum dunk
s
(3)
ranking
Personal
Interest
(3)
Will save lots Time
of energy
commitment
(6)
(3)
Total
Switch that
Cody
2
turns charger
Tatiana 2
of computer
Tshiamo 2
off when
battery is full
1
4
1
26
3
4
0
2
4
1
Roof Top
Garden
Cody
2
3
4
0
Tatiana
3
1
5
0
Tshiamo 1
1
4
0
Solar Paint to Cody
3
convert solar
Tatiana 3
energy to
Tshiamo 3
electrical
3
6
0
2
6
0
2
6
1
Switch that
adjust
intensity of
light during
the day
Cody
3
3
5
2
Tatiana
3
3
5
2
Tshiamo 3
3
5
1
Box that
insulates hot
pot to soften
food before
cooking
Cody
2
1
4
3
Tatiana
3
2
4
3
Tshiamo 2
3
4
3
24
35
38
34
Table 1: Ranking of different factors to consider when choosing one design from all the proposed
designs.
Design FRDPARRC
Functional
Requirement
s
Design Parameters
Analysis
Research
Risks
Countermeasur
es
Conserves
energy by
dimming
or turning
off lights
when
there is
enough
sunlight in
the room
Light sensing
device will collect
information about
brightness of
sunlight, and send it
to dimmer switch,
which will dim the
light of lamp
6000 kW/hours
of energy
per semester
can be wasted
on lights that
are left on
unnecessarily
during the day
A photodiode
can produce a
voltage
depending on
the intensity of
light it is
exposed to. A
dimmer switch
produces
different
brightness in
attached lamp
depending on
how much
input voltage
there is in part
of its circuit. A
photodiode can
therefore be
used together
with a dimmer
switch to
control
intensity of
light coming
from lamp
Integrating
dimmer switch
with wiring of
building could
cause fires if
not done
properly.
A dimmer
switch can be
made
separately and
used with a
lamp, and not
connected to
the building
lights
safe
Small scale
prototype- could
make dimmer
switch and not
connect it to
building circuitry.
With a small
device
connected to
one lamp it
will be easy to
detect any
faults, and any
faults will be
less dangerous
to the user
compared to a
large device
integrated to
the whole
building circuit
Risks of
electrocution
could result if
one touches
the conducting
wires on
dimmer switch
circuit.
The exposed
metal in
dimmer switch
circuit can be
covered with
electric tape
Ergonomics
and
aesthetics
The device will be
small and compact.
It should be able to
fit on the window
sill
If the device is
kept in the
room it will
respond to
light produced
by the lamp, to
make sure it
only responds
to sunlight it
should be
made such that
it can be kept
by the window,
behind the
blinds
economical
Budget restraintunder $200
Estimated cost
of device is
$125.00
A photodiode
detects any
visible light,
not only the
one from the
sun, so even
light from the
lamp will
make it
produce a
voltage
Table 2 Design FRDPARRC
Research and Help
For the construction of the Light Sensitive Dimmer, we met with several people to discuss the
process of building the device. We met several times with our professor, David Custer, to discuss
the possibility of designing the device as well as to get advice on which components to buy. We
also met with two upperclassmen from the dorm that Tatiana lives in—East Campus. Their names
are Scott Morrison and Chris Merrill, and they are majoring in Physics and course 6—electrical
engineering, respectively. They consulted us through the process of wiring, soldering, putting
together the circuit for the dimmer switch, and connecting the photo diode with the dimmer switch.
Results
When testing the Light Sensitive Dimmer it functioned as anticipated. We connected it to a lamp
placed in a dark room, and used a small flashlight to shine onto the light sensor. We started by
perpetually moving the flashlight closer to the light sensor. As we did that, we noticed that the light
bulb on the lamp was gradually dimming. When we brought the flashlight right near the light
sensor to provide full brightness, the light bulb on the lamp dimmed completely, as expected. We
then slowly moved the flashlight away from the light sensor and noticed gradual increase in the
light coming from the lamp. Then we covered the light sensor completely to provide full darkness,
and the bulb on the lamp gave out maximum light. This indicated that the light sensor was sending
the correct input to the dimmer switch and the dimmer switch was successful into receiving and
processing the voltage information as to make the bulb operate accordingly.
Conclusion
Throughout the process of conception, design, prototype, and evaluation of the Light Sensitive
Dimmer, we did not have any major difficulties. When testing the device at the end, we got
promising results. The small experiment that we did indicated that the Light Sensitive Dimmer
would work very well when connected to a greater light source as to control the light level of a
whole room. We, therefore, conclude that our project was a success and the Light Sensitive
Dimmer has a great potential for saving energy when commercially produced and distributed.
Qualifications of primary investigators
As first year MIT students, this year, we have had the experience of building a device that keeps
coffee hot for two hours, and one that heats water using solar energy. Additionally, each of us has
built several projects in high school, as part of the curriculum as well as during summer programs
and other extracurricular activities.