Final Project Report: Self-Sustaining Solar Sensor

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Draft

F
DR Report


Abstract



The goal of our project
was

to create a
self
-
sustaining light sensor system to predict the
efficiency of solar panels. With Green Energy
growing in popularity and people becoming
more aware of renewable forms of energy; solar
power is now a more common source of energy.
Although sol
ar power is cleaner, it can be an
expensive investment costing thousands of
dollars. Before making a huge investment like
this, a smart consumer will want to know how
much this product will benefit them and if it will
be worth the power savings in the long

run. This
is where our project comes into play. The light
sensing system
we created

provide
s

real data
that is collected periodically throughout each day
for
an extended period of time
. This is very
useful information since
before our project
these
values

were

often just generic approximations
based on the geographical location o
n the globe.
Our collected data
provide
s

insight to which
direction the solar panels should be oriented and
at which angle will give the optimal results. In
addition to this inform
ation it will also be
possible to predict how much energy the solar
panels will generate throughout the year. By
providing the user with these res
ults in a clear
graphical form
, they will be able to make an
educated decision.


I.
Introduction

Our project
is aimed toward the solar energy
market. Solar panels are an expensive investment
and it is important that the user is getting the full
potential from them. It would be a waste to spend
thousands of dollars and be sacrificing valuable
energy because the pa
nels aren’t oriented in the
optimal direction or angle.




After speaking with commercial sales
representatives

of one of New England’s largest
solar panel companies, Nexamp, we found out the
industry already has many tools in place for similar
functional
ity that our unit has. By using tools

like
the Solmetric Suneye, a ha
ndheld fisheye camera
which calculates shading factors in conjunction with
PVWatts.com which is a site that can calculate
average weather patterns for specific areas, a very
accurate calc
ulation for power savings can be
calculated. Unfo
rtunately these metrics can be
very
expensive, and the real battle for efficient solar
panel installations is in the design and installment
phases rather than the actual production. Our project
could offer a
n alternative which is cheaper than and
just as accurate as other industry technology.

Since solar panels are often placed in fairly
inaccessible places and to make
our project

convenient for the user, we need to make our design
completely autonomous. The
re are many different
problems that need to be overcome to achieve this.
To power our device for
an indefinite duration

without having the user replace the batteries we
are
using

a solar panel to recharge lithium ion batteries.
Throughout the day we will t
ake light samples from
an array of sensors

and store them into

memory.
Then we will transmit this data to our database
through the use of mobile internet (GPRS). This
col
lected data will then be access
ible

through a
python application
. You
are

able to review the data
overtime and it will be able to help you predict the
exact angle that your panel should be placed.

To achieve
this, our

system
(refer to fig. 2)
is

charged by solar power and will use the cellular
network to transmit data.





Final

Project

Report:

Self
-
Sustaining Solar Sensor


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II
. Design




Figure 1
-

High l
evel block diagram of system


Our system is composed of three main parts

(
r
efer to fig.1)
, the sensor system,
a python
application
, and a server tying the two together.
Both the sensor system and
python

application are
capab
le of connecting to the server over the
internet.


Figure
2
-

Block Diagram of Sensor System



Figure 3


Sensor Array


The sensor system itself is composed of 4
main blocks, a power supply, microprocessor, the
sensor network, and lastly the transmitter

for
connecting to the MySQL server


The sensor will be made of a series of light
intensity detectors arranged in a triangular
configuration as shown in figure
3
.

.



Figure
4
. Block Diagram of Energy Harvesting solution.


The Power supply is composed of
four parts
,
a Solar panel, Li
-
Ion Solar Charger, DC/DC Step
down Converter and 7.2V Battery pack as seen in
Fig. 3
,
which

connects directly to the
Seeduino

microprocessor. The power supply uses solar
energy to recharge batteries. This is do
ne by a Li
-
Ion b
attery charger
which regulates current and
voltage for charging.


The Solar panel supplies a variable voltage,
variable current depending on light intensity, but
averages at 12V and 100mA. The Li
-
Ion Solar
charger takes this input voltage and regulates,
pr
oviding constant current or constant voltage
modes to recharge the batter
y

depending on the
charge level of the battery. The DC/DC step down
Buck converter is used to regulate the 7.2V from the
batteries, into 5V that the
Seeduino board

(refer to
fig.4)

an
d transmitter require.



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Design of Software


The general concept for our
python

design
was an application that could graphically display
data to a user and a user can check incoming data in
real time. This meant that the application needed
some sort of da
tabase support. For a temporary
solution we have a M
yS
ql database hosted for free
on WestHost
.com
.
Because this database is free it
limits

our connections and storage space so a
different database will be implemented for the
finished product. Our database
currently has a
single table which keeps track of sensor value and
date/time stamps in which the data was taken. To
populate and pull data to and from our database our
group has written
PHP

with simple INSERT and
SELECT

Sql statements which are located at
http://umasssdp.atwebpages.com
.

These pages
allow us to manually insert data for testing purposes
as well as pull data off of the server and encode it as
a JSON (Java Script Object Notation) object. A
JSON object is encoded as a string of data that we
pars
e in our application.




Fig.
5

-

Client (Android Application) Server (
PHP
/MySql)
Diagram


Power saving and angle algorithm design


The topic of choosing the most accurate
angle for our solar panel involves vector math
design for determining the normal o
f the solar panel
that is most beneficial for any given spot.

The data collected from the 13 sensors is
processed by a server
-
side python

program. Using
ScyPy, a scientific module for python the sensor
data is interpolated to find the angle of the greatest

light intensity. To carry out this interpolation, we
first consider that the data points
exist in spherical
coordinates, with Theta describing the angle around
the base, with 0 degrees being east; and Phi being
the elevation, 45 degrees being the middle r
ow of
sensors, and 90 degrees for the topmost. This would
create a 4
-
dimensional system to interpolate over,
when the value at each sensor and the radius,
distance from the center of the dome to the sensor
itself are taking into account. To simplify this t
he
sensors are mapped using their Theta and Phi values
to a rectangular grid with the sample value
representing the magnitude, effectively cutting the
system into three dimensions. A method of
interpolation known as
bilinear

interpolation is then
used to f
it a spline curve over the data set. The
position and value of the highest point corresponds
to the direction of the brightest light. If
we
were to
imagine a point
-
light, the direction corresponds to
the side the point
-
light is on.



Seeduino

Design

Currently we are using the
Seeeduino
Stalker V2.1

board with
an

ATmega
328

microcontroller. This board provides 14 digital
in/out pins,
6

analog inputs, a 16 MHz crystal
oscillator,

a Real Time Clock,
and
SD card slot
.
We
used two 8:1 multiplexers controlle
d by three digital
out pins on the stalker board to control our 13
sequential
reads

from our light sensors
.


Our sensor device design will consist of 13
light sensors. When the
Seeduino

wakes from a
sleep mode it will read the light intensity from each
of
these sensors. Each reading will be from one to
two bytes, which will then be saved in memory until
it is sent to the server using the GPRS.

Once the
values are sent, the flash memory is wiped clean so
the values do not continually fill up memory.


The boa
rd has a 5V operating voltage,
which is what we designed our lithium ion batteries
to supply. There are
2 gigabytes of flash memory

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that can be used to store the data from the sensors.
The ATmega
328

includes five different sleep
modes: idle, ADC noise redu
ction, power
-
down,
power
-
save, and standby. An interrupt signal can be
used to wake the chip from any of these sleep
modes. We are interested in using the power
-
down
sleep mode because it saves the most power. An
external interrupt will be used to wake the

board out
of this sleep.

We calculate the power from the sun by
measuring the amount of sunlight that reaches the
earth. This value is called the insolation which is a
combination between luminance and the
wavelength of the light. Insolation is measured
in
Watts per meter squared (W/M^2). The instrument
used to measure this value is known as a
pyranometer
, except instead of measuring a specific
wavelength of light a pyranometer takes into
consideration the entire spectrum of ultraviolet
radiation
. These d
evices can be very expensive if an
accurately calibrated device is needed. For our
purposes we buil
t

pyranometers cheaply which we
can calibrate to offset its inaccuracy.

Each of our 13 sensors have a slightly
different spectral response so they needed to

be
normalized. We did this by applying a controlled
light source to all of the sensors. From this we were
able to make a one point calibration. Because of this
calibration each sensor was uniform in respect to
the other sensors.

By taking empirical data
throughout several
times of the day, we were able to create a scaling
factor for our sensor values to calculate irradiance.
This irradiance was eventually turned into an
expected power and money saved by the user.

The sensors that

we

chose to use were the
silicon photo detectors from DigiKey. This sensor
creates a voltage from the light, measuring the
current through a 1k resistor will give us an
irradiance value.



Fig
7
.

Reponses over different wavelength of a photodiode we
plan on using for our pyranom
eters


Although this curve

(refer to fig.7)

shows
that the diode we are planning to use isn’t uniform
and has a higher sensitivity for infrared than other
wavelengths, it gives us an accurate reading without
spending hundreds or thousands of dollars.

From
our insolation or irradiance values
from our pyranometers we can use a general
performance for solar panels which is measured
with three values: irradiance, solar spectrum of air
mass, and temperature. This calculation will return
an efficiency of light en
ergy which will actually be
turned into electrical energy from the solar panel.
This efficiency can be applied to different solar
p
anels and a Kilowatt per month
value can be
found. Based on prices for power in different states
we will be able to calculate

the potential final dollar
value that could be saved each month by a customer
using our project.



III.
FP
R Prototype Implementation


Selection of Microcontroller


Our sensing device should be able to operate
completely on its own once it is installed and

placed
in the desired location. The microcontroller has to
be capable of many different task
s to achieve this.
The
our microcontroller consists of being able to
wake up from a sleep mode, retrieve and save data
from the sensors, send data to the database
via
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GPRS, and put itself back into sleep mode until the
next interrupt.

We decided on an
Seeduino

microcontroller
for our project. We looked into many other
alternatives including
several other

low power
micro
controllers, but taking into consideration the

recommendations from our project evaluators we
decided on the
Seeduino

board. The
Seeduino

is an
open source microcontroller

which is easy to setup.
In addition
,

there is also a lot of s
upport for this
microcontroller

since many people use this as a
proto
typing board.





B.

Selection of Battery Type


Lithium
-
Ion batteries were chosen for their
higher capacity than other rechargeable batteries.
The standard operating voltage is also higher than.
Individual cells can be placed in series to increase
voltage, o
r in parallel to increase capacity. By
configuring 4 batteries such that there are 2 parallel
sets of 2 batteries in series increase fault tolerance
(
3
). Standard lithium
-
Ion batteries are 3.7V, and are
charged at a 4.2 volts +/
-

50mV/cell. (
3
) By placing
two cells in series, the operating voltage is 7.4 volts,
with a charging voltage of 8.4. Charging of a
lithium
-
ion battery is
difficult, requiring 2 phases.
The f
irst

stage is
constant current to charge
the
battery
and then a constant voltage to top off th
e
battery. (
3
) IT is also very important that Lithium
ion batteries do not experience extreme temperature
or voltage stress, as they will explode if operated
under unusual conditions.


C.


Selection Step Down Converter.


The sensor

system

uses

an
Seeduino

mic
ro
controller which requires 5V to operate. Given that
our battery pack is 7.4 volts, a DC/DC step down
converter is needed. A low power, energy efficient
LT3480 DC/DC Buck converter was donated by
Linear Technology to fit this purpose. The circuit
allows
for an input of 6 to 38 volts, and output a
steady 5 volts. This circuit is ideal for our project,
as it consumes very little power, reaching 87%
efficiency for our standard operating conditions of
.5 Amps and 7.2 Volts.


Figure.

8
: Efficiency vs. Load
current for DC/DC step down
voltage regulator


D.

Selection of Solar powered

battery charger


The most energy efficient way to use energy
harvesting

is

to charge a lithium
-
ion battery

(refer to
fig.8)

is to use a solar panel. A circuit is required to
regulate

the highly volatile nature of a solar panel
for charging of a battery pack. Linear Technology
donated the LT3652, a Monolithic step
-
down
battery charger that supports a wide input voltage
range. The board accepts an input voltage of 12
-
38V and outputs a s
teady 8.4 volts. The board
supports input currents as high as 2A.

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Figure.
9
: Input Voltage vs Output Current for Solar charger


The board also has several advanced
features. A single resistor, R
sense

is used to specify
the average charging current

(refer to fig.9,
10,11
)
.
This is set to 0.050 ohms to allow a maximum
charge of 2A. A C/10 jumper allows the board to
stop charging when a minimum current threshold is
reached. This is important to prevent the batteries
from being overcharged and posibly
explode, as
well as extending the battery life.




Figure
10
. Solar Panel Voltage vs time. Here loaded means
connected to the LT3652 Solar Charger.



Figure
1
1
. Output voltage, vs Input voltage of the LT3652.


E.

Selection of Transmitter


For transmitting w
e decided that we would
use GPRS (General Packet Radio Service) better
known as mobile internet. We considered WIFI and
Bluetooth but for these they have limited ranged
and would require the user to setup a gateway for it
to connect to the internet. With G
PRS we are using
an existing infrastructure through which we can
connect to the internet and update the database
remotely. Due to the fact that we are using the cell
networks, we need

to

pay for this use. For both
At&t and T
-
Mobile, both
are
Global
System
for
Mobile Communication

carriers, we are looking at
around $30 a month for unlimited data, which is
what people usually think of when they think of
mobile internet. Since this would be extremely
expensive for our application and that we are
transmitting s
mall amount of data we will use a
pre
paid basis. Since T
-
Mobile
offers prepaid data,
we need to pay $
2.00 per day we use transmission,
and we can use an unlimited amount for that day
.


0
2
4
6
8
10
12
14
16
18
0
3
6
9
12
15
18
21
24
27
30
33
36
39
42
45
Voltage (V)

Time (s)

Solar Panel Voltage vs
Time

Loaded
Unloaded
0
2
4
6
8
10
0
3
6
9
12
15
18
21
24
27
30
Output Voltage (Average)

Input Voltage

Output Voltage

Output
Voltage
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Figure 1
2
.
Standard IPv4 Transmission Control Protocol

constructed by the microcontroller and passed to the GPRS for
transmission



Our if we sense every 15 minutes for the 12
hours of possible daylight, we will have 1200 bytes

each day. We will then create packets for each of
these readings send in

Standard
TCP/IP packet
s

(refer to fig. 12)
.



The design of the GPRS is an interface to a
wireless module
-
sim900 chip. This is a Quad
-
band
(850/900/1800/1900MHz
)

GSM/GPRS
module. To
interact with this chip we need to send it AT
commands through a serial connection
. These
commands are sent to the module to tell it what to
do, which is the same way that a cell phone
communicates with the module.



F.

Selection of Software


PHP

was used to script the interaction between
the GPRS transmitter and the database as well as
the interaction between the database and the android
application. Once the signal has been set to the
internet from the GRPS on our device a script to
populate our

database is hit.
PHP

is a very common
general purpose scripting language part of LAMP
(Linux, Apache, MySql,
PHP

or Python) which is
open source avoiding extra costs for licensing
Microsoft or apple software products. Our project
also uses MySql another p
art of the LAMP softw
are
bundle for data storage of
our sensor data.


Python was chosen for the server side
software due to how easy it is to develop for.
Python is a Rapid prototyping language, and
includes packages to develop scientific computing
softwar
e. Within Python, PyQt was chosen because
it is a RAD tool, and ScyPy was chosen because it
contains functions for interpolating data points.



V.
Project Management


A.

Team Member Roles


The roles for each team member were
determined after splitting up the project into its
individual parts. The Project was split into 4 main
areas: the power supply and microprocessor, the
transmitter, the sql server and networking, and the
android applicati
on. After splitting the project into
its parts each team member chose an area of
interest. Andrew is responsible for the
support of

the
MyS
ql s
erver
, the Website, Arduino
Programming and testing
. Matt is working on the
MyS
ql server and the transmitter. Tyl
er is working
on the
seeduino

processor, integrating the sensor,
and C code for the transmitter. Nick is working on
the power supply
, the python application

and aiding
in the development of the arduino software.


B.

Summary and conclusions


This report has ou
tlined our approach to our
senior design project as well as final results and
explains the role of each member on the team. The
original idea was to create a general purpose, cheap,
sensor array system; however a specific application
was required to demons
trate the technology. The
new application also needs to be easy to
demonstrate on SDP day at the end of the academic
year. In order to come up with a specific application
we began emailing various companies and groups
that could potentially be interested i
n an energy
harvesting sensor. Even with the direction our group
took this project, it should be stressed that this
product could be used for any sensor array
application.




REFERENCES


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(1)
(2011)
LT3652 Power Tracking 2A Battery
Charger Linear Tech Data

Sheet.

Available:
http://www.linear.com/product/LT3652

(2)

(2011)

LT3480EMSE 2A, 38V Step Down
switching regulator Linear Tech Data Sheet

Available:
http://www.datasheetarchive.com/LT3480EMSE
-
datasheet.html

(3)

Isidor Buchmann
.

(
2011
)

Charging Lituim Ion
Available:
http://batteryuniversity.com/learn/article/

charging_lithium_ion_batteries

(4) (2011) Photonic Detectors Available:
http://media.digikey.com/pdf/Data%20

Sheets/Photonic%20Detetectors%20Inc%20PDFs/P
DB
-
C135
-
F.pdf

(5)
(3 December 2011) IPV4 Availab
le:
http://en.wikipedia.org/wiki/IPv4

(6) (2009) Arduino Duemilanove Available:
http://arduino.cc/en/Main/arduinoBoard

Duemilanove

(7)

(1 December 2011) Seeeduino Stalker v 2.1
Available: http://www.seeedstudio.com/wiki/
Seeeduino_Stalker_v2.1

(8)
(2010)
Atrecto
. Connecting to MySql Database


(
10)

Brad Hunter
, Commercial Sales Director
Nexamp
. Personal Interview. December 2011



APPENDIX


A.

Application of Science, Mathematics and
Engineering


The Self Sustaining Sensor System is an
interdisciplinary project

that uses many topics from
classes in the electrical and computer engineering
curriculum. The specific areas that apply are java
programming (ECE 122, 242), circuit and power
system design (ECE 211, 212, 323, 324), networks
and the internet (ECE 374), vec
tor math (Math 233,
CS 473), and embedded systems and
microcontroller programming (ECE 112, 353, 354).
Python programming was a key part of our project.
Our python application uses python libraries to
perform tasks like storing and sorting data,
connecting

with a network and parsing data streams.
Python was used to create our supporting
application for our S4 hardware device. Another
class ECE 374 taught us the fundamentals of
network technology such as our GPRS device
which is used for transmitting our dat
a from our
device to the internet and how to develop software
such as http posts to populate our database and grab
the data from our java application. To actually use
the data that our device records we need to be able
to calculate the amount of light rece
ived by the
sensors in a meaningful way. This involves some
vector math to determine the normal in which a
solar panel would have optimal performance on a
rooftop. In our embedded systems programming
classes such as ECE 112, 353 and 354 we
developed the sk
ills we need in our current project
for working with an Atmega328 microprocessor
onboard our Seeeduino Stalker microcontroller.
Finally, circuit design and power systems in ECE
211, 212, 323 and 324 taught us how to calculate,
design and build our electron
ic systems. Our project
involves a power system that charges several
batteries and runs a microcontroller. This means
that we need very specific specifications of power,
voltage and current in several stages of our project
to get the whole thing to run pro
perly.



B.

Design and Performance of Experiments,
Data Analysis and Interpretation


For FDR we have tried to get as much data and
testing done as we could. We spent a lot of time
outside with our sensors calibrating them at
different times of the day. By
doing this we got
fairly good accuracy in predicting the power output
of our solar panels that we used for testing. In lab
we have been able to see our solar panel works as
expected (Output of 12+ volts) and our power
circuit is stepping down the input vol
tage to 5v for
our microcontroller. The charging stage of our
power supply is also sufficient for charging our
lithium ion batteries.

To test if our device is calculating correct
optimal orientation we had our sensing array set up
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inside in an environment
where we can control the
lighting. We used a flashlight shine on a specific
section of our sensor array. This will allow us to
know what the optimal
orientation actually is. We
then

compared this known orientation with the
orientation that our device calcu
lates. By comparing
these results we

a
re able to assess how accurate o
u
r
device is and how we can improve its design.

The second experiment required us to take
readings of how much power an actual solar panel
is generating and comparing it with what our
device
is estimating for power. We did this by setting up a
solar panel and our device in the same area and at
the same time for an hour. Throughout this hour we
reco
r
ded the power that the solar panel generated
and used this to get the average kilowatt ho
ur value
for the solar panel. We compared this value with
what our device calculated to check its accuracy.


C.
Design of System, Component or Process
to Meet Desired

Needs within Realistic Constraints


Our projects requirements include
d
:


-

Low Power, maxim
um of 5v peak with
drawing no more than 2A from our
power supply

-

Python

Application for calculating best
performance of static solar panel,
graphically displaying sensor data and a
good estimate to dollar value saved by a
user on a monthly basis

-

A sensor a
rray able to accurately sense
light intensity of the sun in a potential
spot for solar panels

-

A hardware device capable of processing
and transmitting sensor data to the
internet

-

A sampling and transmission cycle that
consumes less power that can be
rechar
ged via our solar panel



These requirements give our group a
realistic set of goals to meet without using terms
that are too vague that a wide range of outcomes
could be determined as satisfactory. Low power has
been a key part of our project from the very first
idea was pitched i
n our brainstorming stage.
Because we wanted our project to be self
-
sustaining
(i.e. solar powered) every part of our project
revolved around a specific voltage and current
requirement. When we were looking for a
transmission system, a power supply and a
m
icrocontroller we had to pick components that
would meet this requirement. The end goal for our
project, which is a solar power sensor (not only is
our device solar powered, it also senses the amount
of light its receiving), is to accurately describe to a
user how much value they can get out of installing
solar panels to power their house. A solar panel
installation is an expensive ordeal and many people
consider it an eye soar on the house and the
community. Green energy can sometimes come at
large monetar
y and social costs. By using some
algorithms within our application we should be able
to accurately show a user how to position a solar
panel for maximum efficiency as well as what that
maximum efficiency will calculate to in a dollar
amount. The requireme
nt for a device capable of
processing and transmitting sensor data to the
internet could be met by many different off the shelf
devices on the market, our job was to choose which
one to use. Our group ended on an
Seeduino

microcontroller because of it low
power and its
amount of open source resources on the Internet.
Because so many hobbyists and developers before
us have worked with this microcontroller it saves us
time during development. A sampling and
transmission cycle that meets our charging
capabilit
y was a simple calculation that involves the
comparison between the power consumed for a
single transmission versus the amount of time
between transmissions we have to recharge the
batteries.


D.
Multi
-
disciplinary Team Functions


Andrew Frieden, CSE:

-

Andr
oid Application development

-

Money saving, power saving and
direction of optimal solar panel
algorithms

-

Web Designer


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Matthew Weydt, CSE:


-

PHP

Web Server development


-

MySql Server development


-

Arduino programming


-

GPRS programming


Nick
Setzer, EE:

-

Solar panel step down converter

-

Power supply system

-

Assist Arduino programming


Tyler Dunn, EE:


-

Sensor testing and Integration


-

Device construction


-

Power system design and testing

-

Assist Arduino and GPRS programming


E.
Identification, Formulation and Solution
of Engineering Problems



The main engineering problem our group
encountered was the communication between
components of our project. Our initial
implementation idea was a very short range
communication via either B
luetooth or USB cable.
Because these did not fit into our projects design
scope as being a wireless ‘autonomous’ sensor,
these ideas were thrown out. Next we turned to long
range communication which conflicted with our
requirement for our device to be low
powered. Long
range communication generally means a high
powered signal is transmitted and requires a
relatively large amount of power. This is where our
group compromised. We decided that with enough
time to recharge a power supply in between
transmission
s, we would be able to sustain our
system indefinitely. The next step was going to the
drawing board and determining our transmission
life cycle. We began by determining how many
samples can fit in a single transmission. If we plan
on using TCP/IP as our n
etworking protocol that
means we have a packet size of 1400 bytes not
including our header. With the amount of sample
data we want to take,
thirteen

integer values for our
thirteen

sensors, two more integers for a date/time
stamp and another integer for a
unique hardware id
to determine which device is transmitting. We are
using almost 40 bytes of data for each sample which
stores over 30 samples in a single transmission.
That means that we could take up to 30 samples in a
day and only transmit once. The po
wer
consumption of the GPRS transmitter allows for a
transmission cycle of a little under an hour and a
half before the batteries can be charged back to full
power.

We have decided that sampling every fifteen
minutes and transmitting once at the en
d of eve
ry
day would give sufficient data and enough time
between transmissions to charge our lithium ion
batteries.


A second major engineering problem we
have encountered in our development of the device
has been the power supply. The different
components of our

project require different voltage
values for operation. For example our solar panel
puts out a constant 12v while our batteries require a
two phase charging, first at a constant current and
constant 8.2v and then back up to 8.4v to top them
off. Because o
f this our group decided we need a
way to step up and down the voltage level of a
power source to accommodate our power supply.




F
.
Understanding of professional and ethical

responsibility


The professional and ethical aspect of our
project is mostly in
two specific areas. Our project
is a tool that will allow customers to have better
information about the effectiveness of “green
energy” and make a more informed decision on
whether or not it is the correct decision for their
location and their financial s
ituation. We hope that
the S4 system will be a benefit to society because it
is technology that will promote the use of clean
energy and better our world. The other area of
concern on a professional level is the look and feel
our device and solar panel ins
tallations will have on
a house and the community surrounding it. The
home is an important place for all families and
many don’t like installing equipment on their
rooftop. Because of this our group would like to
minimize the size and increase the aestheti
c appeal
of our device for the benefit of the customer.

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G
.
Team Communication


Several forms of communication are
necessary for us to piece together our project. Right
now we have a Dropbox account that keeps our
versioned software and SDP related material in one
spot. We date and time stamp all our files so that
our most up to date
files can be downloaded
anywhere by anyone in our group. Source control is
an important aspect of software development and
keeps group members from checking out the same
piece of work and rewriting it twice. Other than
Dropbox our group communicates via em
ail to meet
up in lab and confirm our workload and deadlines.



H
.
Understanding the impact of engineering
solutions in a global, economic, environmental and
societal context


Our project has a potentially large impact
economically and environmentally because it
promotes clean renewable energy. With a rapidly
developing world, new energy sources are always in
demand. Most countries resort to the burning of
massive amounts of fos
sil fuels like coal and oil.
These resources are finite and are being used up at
an alarming rate. Not only are these resources going
to run out but they have a negative environmental
impact on the world. Burning fossil fuels results in
effects such as aci
d rain and release other dangerous
chemicals like arsenic and mercury. The world can
be stubborn to change especially when its money
out of individuals pockets. With our device, an easy
decision can be made to move to clean energy in an
economic fashion. T
he more you know about your
energy consumption and what technology can save
you money and power usage, the better off
everyone will be. Our projects societal factors are
only in its ability to shift peoples view on energy.
Hopefully with enough people swit
ching
to
clean
energy sources it could become the new “cool” or
“smart” standard in a soc
ial setting


Our product could potentially have a
negative social impact. Solar panels are often cited
as being very ugly, when placed on roof tops. Our
devices goal i
s to prove placing solar panels will be
cost effective for an individual. If the device proves
popular it will increase the number of solar panels
installed.



I.

Application of material acquired outside of
coursework


A large amount of our software for this
course
involved the LAMP (Linux, Apache, MySql, PHP)
open source platform which is material that several
of our group members learned outside of school in
internships. With no previous coursework in
databases or server side scripting we were able to
apply
our knowledge from our internship to our
senior design project. Classes such as networking
and computer systems lab taught us some of the
fundamentals of how a network connection works,
but we never implemented these protocols ourselves
into a real project
.



J.

Knowledge of contemporary issues


As mentioned previously environmental impact
from dirty energy is becoming more prevalent on
the planet, in politics and in our everyday lives. A
major imminent problem on mankind is the effect of
global warming and w
hat it could mean for the
earth. Many forms of sensing networks, climate
scientists and government appointed panels have
been working towards a solution and possibly
policy changes to help the reduce the footprint
being left on our planet by humans. But, e
veryone,
not just government and climate scientists, can help.
If our new product were to go into the market place
as an incentive for individuals to install solar panel
systems, it could have a greatly positive impact.
Clearly this impact would be small f
or each
installation but the idea is to create a shift to clean
technologies.


K.

Use of modern engineering techniques and
tools


(1)

Notepad++ and the python compiler

(2)

Arduino Development Environment was
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used as our development environment for
our embedded
Arduino code. The Arduino
IDE uses the GCC compiler

(3)

Circuit analysis tools such as oscilloscope,
amperage and volt meter were used to test
our power supply outputs for each stage.
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