1. Contactless Power Line Monitoring Unit
Nathan A. Crocker (EE Student), Broc A. Friend (EE Student), Levi D. Lewis (EE
Student), Matthew L. Partridge (EE Student), Michael I. Wegerson (EE Student),
and Dr. Arash Nejadpak (EE Faculty)
n.crocker, broc.friend, levi.lewis, matt.partridge, michael.wegerson, and arash.nejadpak@und.edu
Abstract- To effectively monitor electrical power
distribution, utility companies require access to transmission
line characteristics in real-time. This requires expensive and
invasive additions to the lines themselves. Today, the available
Power Line Monitoring Units (PLMU) prevent the full
realization of a smart electrical power distribution grid. Self-
powered sensor units are a new approach to analyzing line
performance. Utilizing low-cost hardware, these units harness
the magnetic flux leakage from the transmission line to power
sensors that noninvasively measure real-time voltage, current,
frequency, phase angle, and power factor. This collected data
will be transmitted over a wireless communications network to
optimize grid performance. Outlined in this paper is a device
that will incorporate all such factors with one key difference:
versatility. This unit will be adaptable to uses with lower
nominal voltages while maintaining performance metrics. An
ideal PLMU would harness 5 watts from the transmission line,
capture user specific parameters, and transmit these results
wirelessly. The test results show that the PLMU is capable of
collecting, processing, and displaying transmission line
characteristics after transmission. The overall system consumes
between approximately 1.5 watts, at times of high load, and 1
watt, at times of low load, of the 5 watts theoretically produced
by the power harvester.
Keywords: Energy Harvesting, Hall Effect Sensor, Self-
powered, Sensor Network, Transmission Line, Ubiquitous
Wireless Sensor Network
I. INTRODUCTION
As electrical demands increase in today’s society,
efficient power distribution is rapidly becoming an issue for
our aging power infrastructure [1]. The concerns raised by
these factors are surrounding reliability and the effective use
of the power distributed through the network. An added level
of monitoring for these systems can assist with identifying
and adjusting the network before future errors occur.
Creating a non-linear, dynamic network to handle these
situations is a viable solution [2].
To achieve that system, four facets are required:
continuous monitoring, reliable communications, timely
error analysis, and a multi-tiered structure of contactless
systems capable of bi-directional communications. This
system would require the ability to seamlessly adapt to
current grid networks, with little to no intrusion, and have a
low economic impact [3]. Other inherent characteristics that
must be addressed are: ease of use, security for physical and
digital data, and the ability to properly operate in harsh
environments while requiring minimal maintenance [4].
II. BACKGROUND AND STATE OF ART
The goal for this project is to produce a refined design for
a contactless power line monitoring unit, modeled after a
Senior Design Project from 2014-2015. This self-powered
unit will monitor the usage of transmission lines to
accurately provide statistics and characteristics for potential
corrective action [5]. The premise behind self-powered
transmission line monitors has been around for quite some
time, however only lately the capabilities of creating a cost
effective device have been a possibility. Institutions like
Georgia Tech are paving the way for future monitoring
systems through their continual effort in research and
development (R&D). They have developed a Smart Wires
technology that converts an existing transmission line into
one that is capable of self-monitoring and capable regulating
its flow of power [6].
The monitoring unit will be contactless, making
installation simplified for a company to integrate into their
system. Instead of shutting down equipment and losing
production time to directly tap into a line, this device can
adhere to the exterior and make all of the necessary
measurements without being intrusive. To do this, the system
will be self-powered by electromagnetically harnessing the
residual magnetic flux from the conductor. This method uses
a magnetic coil wound against a magnetic core material, with
its layers constructed from permeable metal [2]. To produce
an adequate harvested voltage, the system will have an
integrated voltage amplifier. This development will make the
transition for companies easier, cheaper, and much safer for
their employees.
Once the unit is installed to the line, it can measure and
calculate all of the necessary characteristics while being
contactless. This data will be collected at a central location
by a data collection application, where it will be sent via Wi-
Fi systems. This is considered a ubiquitous wireless sensor
network (USN) and have been implemented in many
different applications. It is in residential homes,
automobiles, cell phones, factories, and many other
applications. Most of these networks are powered by
batteries to allow the devices mobility; however, using
batteries in a monitoring unit is impractical, due to the
expanse of the sensor networks and the finite lifespan of
rechargeable batteries [1]. Elimination of batteries will also
be a safer path, environmentally, as disposal will no longer
be necessary [4].
Wirelessly sending information creates convenience for
the user in the form of fewer wires and a more convenient

2. method of accessing acquired data. Wireless is widely
considered the future for measurement devices as it reduces
the space and weight requirements [7]. It also warrants the
opportunity to take measurements in situations not possible
for wired devices [7]. When looking at the number of sensors
collectively working on the power grid, eliminating the need
of wires will considerably reduce the overall grid
modification costs [3].
III. ETHICAL ADVANTAGES
The ethical advantage to using the Power Line
Monitoring Unit as it creates a safer environment for
workers. The unit would eliminate the need for an employee
to enter a potentially dangerous environment when checking
a power line in a power outage. With an array of units the
user would be able to pinpoint where the power line faulted.
Besides initial installation the project minimizes harm to the
user, because it is contactless and nonintrusive. This creates
a situation where the installer would not need to terminate or
contact any electrical components. Overall the project
simplifies and creates a safer environment in the realm of
power line monitoring.
IV. SYSTEM DESIGN
The current project design can be divided into four
separate subsections: power system, transmission line
characterization, microcontroller, and wireless
communications. A block diagram describing the system
overview can be seen in Fig. 1. The power subsystem
consists of the harvesting coils, power conditioning circuits,
power storage, and distributes power to the other
subsections. The responsibility of the sensor section is to
capture transmission line characteristics, such as line voltage
and line current, for monitoring. The microcontroller
processes the sensor data, interpolate this data to generate a
properly scaled amperage characteristic, and prepare this
data for wireless transmission. Finally, the wireless
communications are necessary for transmitting the captured
and computed power line characteristics back to the end user.
Design details and testing efforts on each respective
subsystems are outlined in the following objectives. Progress
of each objective shown in the Project Gantt Chart in
Appendix A.
Objective A: Develop Self-sufficient, Contactless Power
System
Task A1: Energy Harvesting Coil (Broc, Levi, and Matt)
In the simplest of terms, this energy harvester circuit
applies the principle of transformer action to harvesting the
magnetic field losses produced by the transmission line and
rectify these losses into usable output voltage for the
Regulation Circuit, discussed in further detail below. Based
on component data sheets it was approximated that the total
power consumption of the system would be roughly 2.5 W
but it is expected of the harvesting coil to provide a voltage
range of 1 V to 10 V with no more than 1 A sent to the Power
Conditioning Circuit, discussed in further detail below.
The design of the energy harvester was developed
utilizing findings from a previous groups’ efforts. These
findings highlight system baselines but the system design
resulted in losses thought to be due to magnetic reluctance in
the air gab between the current carrying conductor (CCC)
and the secondary windings of the harvester. Additional
losses may be a result of the placement of the coil
windings in proximity to the primary CCC, since the toroid
coils that were used had a larger inner diameter than the
outer diameter of the conductor [5]. Though these findings
stand as a good basis for starting, the need for further design
modifications and prototype iterations were necessary. To
address the design concerns, the 3D computer model of the
harvesting coil was reevaluated, with specific attention paid
to the amount of harvested power. To determine the best
possible output, multiple model versions were created,
simulating changes in the following parameters: number of
secondary turns, the current of the primary CCC, the length
of core, and the properties of the core material. Such
iterations, seen in Fig. 2 and Fig. 3, represent two varying
designs, showing much different results. In Fig. 2, the
proposed coil design utilizing 20 secondary turns, 5 A on the
Figure 1. System Block Diagram

3. primary CCC, 35 mm long core, and a N95 Ferrite core
material with relative permeability of 3000, produced an
output of only 52 mW.
Figure 2. Initial 3D Computer Modeled Harvester Coil, 20 Secondary
Turns
Figure 3. Initial 2D Computer Modeled Harvester Coil, 30 Secondary
Turns
Comparatively, in Fig. 3, the coil design was completely
redesigned to represent a 2D Design, meaning the portion of
the coils that wrap around the face of the core are neglected
from the design, simplifying the relative time to simulate. To
simulate the design in Fig. 2, it took the program, infolytica
MagNet, roughly 30 minutes to calculate the expected output
with the given design constraints, while it took less than 5
minutes to simulate the design in Fig. 3. This 2D design
modified the aforementioned parameters of the 3D design to
the following values: 30 secondary turns, 10 A on the
primary CCC, 100 mm long core, and the same core material
as previous. This combination of parameters provides a
higher output power of 5.45 W and is the most viable
iteration to date. Though these simulations are operating with
a 5 A to 10 A input current on the CCC, it should be noted
that these levels of current are not ideal to work with in
laboratory settings. We have devised methods to inject lower
nominal currents into the CCC, while making reading larger
values. One method is to wrap the CCC around the core,
increasing the number of primary turns and the amount of
magnetic flux available.
To further advance the computer model design, we
conducted a literature review on different core shapes and
materials. Findings show that there are two primary core
shapes, cores with a circular inner radius and cores that are
“C” shaped. Advantages of using a circular inner radius core
are that they produce equal draw of the magnetic flux,
allowing our system to maximize its harvesting potential. On
the other hand, a “C” shaped core would provide the smallest
opening possible to allow both the secondary turns and the
CCC to pass through the center. Since the distance between
the harvesting coil and the CCC has an effect on the output,
this too could help maximize its potential. As for the best
core materials, those with high magnetic properties, such as
iron, nickel and cobalt, are the most viable. We have not
definitively made a decision on either of the core shapes or
any of the materials as time and resources would not allow
for a fully customized core order.
In addition to core characteristics, considerations for ease
of placement on live powerlines and how to maintain an
effective distance between the inner radius of the coil and the
outer radius of the CCC have been made. It has been found
that a nonconductive spacing material will allow the unit to
sit on the line evenly, eliminating shifting. A static placement
will not only provide reliable measurements but will reduce
any jostling from power line sway in volatile weather.
Figure 4. 2016 Prototype Traditional Power Transformer
The end goal for this Harvester Design was to have the
prototype manufactured to specifications but due to a lack of
resources and time, it was decided best to create a traditional
power transformer, to further enhance the proof of concept.
This transformer is not meant to replace the need of the
contactless Energy Harvester Coil but to provide the
Rectifying and Regulation Circuitry with a signal mimicking
that of the potential output from the harvester coil. The
difference between a harvester and a transformer being that
the harvester is wrapped around a power line and absorbs the
flux leakage while the transformer will be placed in line with
the power line.
The transformer prototype can be seen in Fig. 4, where
the blue wire is the primary turns, connected to the power
source in series, and the black wrapped wires are the
secondary turns and hardwired to the PLMU power system.

4. This prototype is made of a bobbin core with 12 primary
windings and 24 secondary windings. The 12:24 turn ratio
was experimentally found using trial and error. Several
iterations were created using varying sizes of available wire
gauges and differing turn ratios. The bobbin core was chosen
because of the ability to control the air gap between to the
primary and secondary sides of the transformer. While
testing a solid circular core, it was shown that regardless of
the voltage input, too much magnetic flux was being created,
thus saturating the core and producing undesirable outputs.
Task A2: Regulation Circuit Design (Michael)
The regulation subsection of the power system conditions
the voltage from the energy harvesting coil and rectifying
circuit, seen in Fig. 5, into the 3.3 V needed by the sensors,
microcontroller, and wireless communication subsections.
This process can be divided into three separate phases, which
are outlined in the following paragraphs.
As shown in Fig. 6, Phase 1 of the design normalizes the
sinusoidal output of the rectifier through the use of several
capacitors and condition the voltage using an integrated
circuit (IC). IC frontrunners for the Voltage Conditioning IC
#1 are the TPS61200 boost converter and the LM117T
regulator, an IC based off the previous group’s design [8].
Benefits of the TPS61200 are an increased conversion
efficiency, which is reported upwards of 90% and a range of
accepted voltage inputs, spanning from 0.3 V up to 5.5 V [9].
The benefits of the LM117T are a wider range of input
voltages, ranging from 1.2 V to 37 V but lacks the efficiency
of the TPS61200 due to the characteristics of a linear
regulator [9]. Results from the analysis of the coil harvester’s
theoretical max output determined which IC was selected in
the final design. Independent of the IC selected, the voltage
output of Voltage Conditioning IC #1 is between 5.2 V and
5.4 V to allow for maximum charging of the super capacitor
power storage system. After the IC rectifier there is a
capacitor to help smooth out the DC signal.
Phase 2 of the conditioning circuit implements current
protection features, displayed in Fig. 5. Having low internal
resistance, the super capacitor array requires a current
limiting resistors to prevent a potential over-current draw on
Voltage Conditioning IC #1. Additionally, blocking diodes
prevent current-backflow from the super capacitors in the
instance where Voltage Conditioning IC #1 powers off,
protecting that IC.
Figure 5. Rectifier with Smoothing Capacitor
Phase 3 of the conditioning circuit contains the super
capacitor array and an additional voltage conditioning IC,
detailed in Fig. 6. Super capacitors were chosen for the
power storage due to their increased charging and
discharging characteristics over traditional battery
technologies.
As an additional safety precaution, a 5.1V Zener diode is
in parallel with the super capacitor array, mitigating the risk
of a voltage spike damaging the capacitors. Due to the linear-
discharging nature of super capacitors, Voltage Conditioning
IC #2 is required to regulate the output of 3.3 V for the
remainder of the electrical components. Voltage
Conditioning IC #2 has been selected to be the TPS61200
boost converter IC due to its high efficiency.
Figure 6. Phases of the Power Conditioning Circuit
Assembly of the three phases has been completed; the
assembled module is shown in Fig. 9. After running tests in
Multisim a Schottky bridge rectifier was chosen as the IC.
The Schottky diode was picked due to the minimal losses that
occurred and is the best for project, the testing circuit can be
seen in Fig. 5. The results of the testing circuit can be seen in
Fig. 7 and Fig. 8. These figures show the graphs of the results
of testing different sized capacitors for the smoothing
capacitor. After tests were ran it was decided to go with a
220 μF capacitor as it was the smallest capacitance to smooth
the signal in 1 second. The super capacitor charged to

5. saturation in roughly 2 minutes, which was too significant of
time and deemed unusable. It was decided that the smaller
capacitor was a better choice due to almost an instant filter
time. This allows the PLMU to gather power in cases of
power down situations. Modifications were performed to
Voltage Conditioning IC #2, removing the under voltage
lockout protection designed for lithium-ion batteries. This
was done to expand the usable voltage range of the IC to
better fit voltage profile of a discharging capacitor.
Testing on the 3 phases has been completed. Capacitor
voltage discharge response has been recorded at varying
input currents and output loads. This is representative of the
system response at a time when the magnetic harvester
would be unable to supply sufficient power to the system.
Output loads were selected to reflect different system states
such as solely powering the microcontroller, both the
microcontroller and the wireless communication powered,
and finally a maximum theoretical power usage. The
following power values are representative of the
aforementioned system states: 0.97 W, 1.77 W, and 2.58 W,
respectively. The graphical results to this testing can be seen
in Table I.
Figure 7. 220 μF Smoothing Capacitor Results
Figure 8. 5 F Smoothing Capacitor Results
Figure 9. Assembled Module of Phase 2 and Phase 3 Components
In order to simulate the varying power input from the
energy harvesting coil, a power supply was used to output
+5V and limit the input current at four levels: 0 mA, 250 mA,
500 mA, and 750 mA. The power supply was connected to
the input terminals of the power conditioning circuit.
Additionally, half watt 27 Ω resistors in groups of two, four,
and six were used to simulate these output power states listed
above. An LED was also attached to the output as a visual
indicator that the output circuit was functioning.
Oscilloscopes to measure the voltage and amp meters to
measure the current were connected to the input and output
terminals of the power conditioning circuits to capture those
characteristics.
Testing began with fully charging the capacitor bank.
Then the input current was limited to one of the above four
levels and the output terminals connected to either two, four,
six, or zero resistors (only LED connected). The input and
output voltage and current were measured with respect time
and recorded. This process was repeated at the remaining
three limited input conditions.
Testing of the capacitor voltage discharge response also
experimentally confirmed the theoretical maximum output
current at a given input voltage provided in the TPS61200
datasheet [8]. Representative of the point where the super
capacitor would be unable to supply enough energy to the
voltage conditioner, this would result in a system shutdown.
Shown in Table I is the average effective time the super
capacitors can provide power to the system at various input
currents and output power draws.
One challenge was overcoming the removal of the under
voltage lockout protection. While removing this effectively
increased the discharge range of the capacitor bank, it also
allowed the conditioning IC to abnormally operate with
insufficient input power. A solution to this challenge would
be to reinstate the under voltage lockout protection at 1.8 V
based on the previously recorded discharge characteristics.

6. TABLE I
3.3 OUTPUT MAINTAINING TIME OF CAPACITOR BANK AT VARIOUS INPUT
AND OUTPUT CONDITIONS
Supply
Current
(mA)
Output Power Draw (W)
0.97 1.77 2.58
0 44.3 s 21.5 s 14.3 s
250 157.1 s 33.3 s 18.6 s
500 --a
--a
28.4 s
750 --a
--a
91.4 s
a
Supply current was sufficient to maintain output power indefinitely.
Objective B: Basic Wireless Communication
Task B1: Transceiver Selection (Matt and Nathan)
In order to wirelessly transmit the data, we first had to
find a device to transmit and receive the data. The ESP8266
was chosen due to the affordability and the size. The
ESP8266 has an internal antenna, which eliminates the need
for an external one, saving space, illustrated in Fig. 11. Each
ESP8266 module has a frequency band of 2.4 – 2.5GHz.
Due to the different operating frequencies of the power lines
and our module interference will be negligible. However
devices close to dense home communities’ operating with
Wi-Fi could create some interference since Wi-Fi in homes
transmit on the bandwidth of 2.412 – 2.484 GHz. Shown in
Fig. 12.
Because of this blacklisting certain channels that Wi-Fi
generally uses will help eliminate that interference. Both the
transmitting and receiving voltage intake is 3.0-3.6 V and
draws a current of 80 mA. The module operates with the Wi-
Fi protocol of 802.11b/g/n, which allows it to form a mesh
network. These protocols can also reach up to 250 meters,
with these distances it will allow the modules to be separated
farther apart than if protocols 802.11a were used since those
can only reach 100 meters [10]. These distances cut costs in
half, and allow fewer modules to be needed. Another idea to
help reduce the number of devices needed is for the master
hub to have a larger and amplified directional antenna. This
allows the antenna to be pointed in the direction of the grid
and since it is directional instead of an omnidirectional
antenna like the wireless transceivers it can reach farther.
A limitation that needs also needs to be considered when
selecting distances of devices is the Fresnel Zone. Radio
frequency broadcasts in an ellipse shaped area between the
two radios, so it isn’t a line of sight path. The primary Fresnel
Zone must be at least 60% clear of any obstruction to ensure
communication between the radios. The zone can be
determined by equation (1). Where r is radius in meters, d is
distance in kilometers, and f is frequency in gigahertz.
Figure 10. System Discharge Response at Various Supply Currents
*Input supply currents of 500 mA and 750 mA were sufficient to supply power to the system indefinitely at the output loads of 0.97 W and 1.77 W.
Therefore, no discharge response was recorded

7. Figure 11. Adafruit HUZZAH ESP8266
r(in meters) = 17.32 × √
d (in Km)
4f (in GHz)
(1)
The module is only rated to go 250 meters which means
to be 60% clear of obstruction the device would have to be
2.8 meters clear in each direction. A typical power line is
over 7.5 meters.
The ESP8266 chip was then placed on a PCB board
which includes a reset button, a button that allows users to
put the chip in bootlegging mode, a red LED, level shifting
on the UART and reset pin, and also an antenna. All these
features allow for an easier user experience. Also allows for
quicker programming and connection. The board also was
preloaded with NodeMCU’s Lua interpreter, which allows a
user to type commands and read out the results over serial
using PuTTY or another SSH client [11].
The ESP8266 operating temperature ranges from -40-125
degrees Celsius. This temperature range allows for use in
almost all environments [10]. In addition to this is the ability
to host a small webpage from the microprocessor. By doing
this the transmitted data from the Piccolo microcontroller
will be displayed at a particular IP address and can be
accessed easily if on the same network.
Objective C: Communication with Piccolo
Microcontroller
Task C1: Communication Using TI Microcontroller (Broc)
Using a Texas Instrument F28069 microcontroller and
VisSim embedded coder, the microcontroller is used to
Figure 12. WiFi Channel Band
communicate between the different sensors used in the
circuit and also the ESP8266 wireless communication
module. The microcontroller is powered via the power
harvesting circuit and consumes between 3.3 VDC and
approximately 100 mA idling, 150 mA at normal operating
conditions and 250 mA at a heavy operating conditions. The
microcontroller samples the data at 200 kHz rate and
consumes 50 percent of its overall computing capabilities.
Using the general-purpose inputs and outputs (GPIO) and
analog to digital conversion pins (ADC), the microcontroller
collects data, and converts the data into usable information
(voltage, current and frequency). This data is converted into
data characters, multiplexed and transmitted using serial
asynchronous transmit/receive (UART).
Figure 11. TMS320F28069 Microcontroller
Task C2: Data Collection and Transmission (Broc)
Data from the different sensors used (hall, voltage, etc.)
is sent as analog signals to the ADC pins where they are
sampled at a 200 kHz or a 5 μs rate. All filtering of input
signals are filtered internally with respect to the
microcontroller, for a more professional and cheaper
product. Low and high pass filters are used to negate effects
of unwanted signal distortion. This data will then be used to
calculate other parameters (frequency) and sent to the WI-FI
module where it will be sent wirelessly to the user in the form
of scaled, usable data [12].
VisSim embedded coder is the software being used to
program the module. The software is a function block type
software that is intuitive enough to generate C++ code based
off block diagrams. The microcontroller used in the piccolo
control card is the TMS320F28069 IC. The microcontroller
IC used is shown in Fig. 13 [12].
The microcontroller and the measurement circuits are
interfaced using the ADC pins on the microcontroller
docking station. The ADC pins are 12 bit converting pins,
therefore the resolution of the pins is 2N
or 4096. The output
from the measurement circuitry is scaled so that 1 mVAC
equals approximately 1 A. The Hall Effect sensor also
measures DC current values, the output of the Hall Effect
sensor measuring a DC source is 1.6433 VDC equaling 0 A.
The output increases linearly as input current increases in the
power line. A simple subtraction of the Hall Effect sensor’s
DC offset is configured to account for the 1.6433 VDC. The
maximum output from the measurement circuitry equals

8. Figure 12. UART Block Diagram Program
2.5V corresponding to 25 A. The voltage input measured
from the sensor is compared to the VREFHI internally (3.3
Volts) and VREFLO (0 Volts) parameters from the
microcontroller. Once the data is sampled at 200 KHz, it is
both sent to the transmitting pins for export and also to a
debug diagram for programming and debugging. The
Transmission program diagram can be seen in Fig. ##. The
diagram illustrates the function block programming and the
UART Communication set up. The diagram includes
creating a transmission queue, initializing to continuously
run, convert ADC results to strings, and starts the
transmitting operation.
The data is transferred to the ESP8266 WiFi module. The
interface between the modules is setup using the GPIO pins
acting as Tx and Rx pins. The controller only needs to
transmit data and does not require any data sent back to the
module. For this application the baud rates of the modules
need to be the same for this application to work. Using these
pins greatly simplifies the integration and streamlines
programming requirements. The microcontroller accounts
for all scaling of the inputted parameters and transmits
correct data to the WI-FI module.
Fig. 14 illustrates the serial UART programming, the data
collected from the ADC pins is sampled and collected as
string values. The WI-FI module requires a stop character at
the end of the string for it to populate the intranet webpage.
As seen in Fig. 14, the program concatenates the ADC data
and a constant stop bit. A summing junction block is used
for this process. The two modules also require pulsing, so the
WI-FI module doesn’t become overpopulated. The pulsing
sequence can also be seen in Fig. 14, a pulse train and unit
step block achieve the pulsing process. The controller pulses
an enable pin internally, outputting the constant transmit
queue length. The serial UART configuration is programmed
at a baud rate of 9600, no parity bits, 1 stop bit, and 16 bit
queue length.
Once the voltage is sensed from the Hall Effect sensor
and measured on the ADC pins, the sensor sample is
converted into a digital value where it is then scaled
according to the scaled factor found from lab testing. The
current (A) digital values found from lab testing on a live
power line can be seen in the plot diagram in Fig. 15. Trace
A1 (bottom line) represents the current values and A4 can be
disregarded.
Figure 13. Averaged Digital Current Value on Trace A1
Figure 14. Voltage Sensor Digital Values
In Fig. 15, channel A1 (bottom trace) is measuring the
amps on a live power line. The trace illustrates a power line
producing 500 mA, and then the line is increased to 1 A. The
microcontroller has a plot function programmed to illustrate
what the module is sensing. Fig. 16 illustrates the voltage
sensor output to the controller. The voltage sensor is
currently working as a digital sensor (ON/OFF), and only

9. senses that there is a load on the line. The output can be seen
in Fig. 16 and illustrates the introduction of a live line to the
sensor. The sensor detects voltage and generates a signal that
the controller processes as a digital value. The same data that
is displayed in Fig. 15 and Fig. 16 is also transmitted to the
WiFi module. Currently the WiFi module is not operational,
so testing the data transmission is represented by using a
500m load. Measurement of voltage and current over the
load results in confirmation data is being transmitted in the
form of voltage and current signals.
Objective D: Implementation of Wireless Network
Task D1: Testing Transmitting/Receiving Voltage versus
Distance (Matt and Nathan)
The ESP8226 Wi-Fi module has arrived as a module
board and nothing attached to it. The first step to making the
module useful was to solder the pins to the board itself. Then
to power and communicate with the module was simple with
the use of a USB to TTL Serial cable. That way the use of a
modern computer would have enough energy to power the
module individually and would be able to communicate via
serial pins. Using the Arduino IDE the module is able to
compile and transfer newly developed code to the microchip.
The use of the IDE from Arduino was done because of the
vast knowledge base that is readily available for this.
Because many programs have already been written for the
ESP 8266, we will have a higher chances of solving some
potential errors with our program. The code will have to be
tailored specifically for the intent of testing the concept first.
This will be done with the construction of the wireless
network. After this has been completed testing for the
connectivity range with the ESP8266 will be conducted. This
will be done by creating a node in an open environment
where we can dynamically change the position of the
Figure 15. Connection to Arduino’s Webpage Confirmation
wireless module in comparison to the node. With this we can
gather signal strengths of these positions and be able to
concisely find distances that would be comfortable for use of
the device.
The usefulness of a mesh network is there can be
numerous nodes on one channel. On each channel there can
be tens of thousands of nodes, depending on the amount of
memory each ESP8266 (node). The different channels are
then separated by the Personal Area Network (PAN) ID.
Illustrated in Fig. 17, shows that each device can be three
different nodes. First is the coordinator node, which is the
main node that stores the information from the whole
network.
Figure 16. Illustration of Mesh Network
Figure 19. LEM HO 25-P/SP33 Current Transducer Output Signals versus
Input Signal (AC)
Then there is the router, which acts like intermediate
nodes, relaying data from the other nodes. Finally it can be
end devices, these are nodes that collect the data and sent it
to the parent device. Before the mesh network can be
constructed in a small scale situation we need to test the
capability of pushing measured values to a collection point.
By doing this we can verify that the values are being sent and
that these values are being transferred correctly. Within a

10. small network that we constructed, the WiFi module code
will direct it to connect and request a webpage.
For testing purposes it will request information from the
website www.Thingspeak.com. Thingspeak is a commonly
used website, for Arduino users, that allows a user to have a
free account where they can create different channels to
collect data. It acquires this data by having multiple sets of
channels that can acquire data directly from a URL that is
predetermined within their system. When the handshake has
happened between the two points the module wirelessly
sends the measured values to a specified address that collect
and graph the information received. By doing this we verify
that not only is recorded information being communicated
outward, but we also authenticate that the transferred data is
not being interfered with and being properly read.
Objective E: Measurement Circuitry
Task E1: Sensor Selection (Levi)
As stated previously, the system makes no direct
electrical connection with the transmission line and is not
intrusive. To accomplish this objective, sensors designed
specifically to measure the produced electric or magnetic
fields are used. To measure the current, a Hall Effect Sensor
is implemented. Hall Effect sensors, much like the power
harvesting coil, utilize the principles of transformers to
produce a voltage signal proportional to that of the magnetic
field. In the case of voltage measurement, the design is based
on capacitive based measuring. A common device utilizing
this methodology is a commercially available voltage tester,
used by electricians or household owners to determine if
wires are electrically live. This device, unlike Hall Effect
sensors, characterizes the electric field through the
capacitance created between a CCC and a conductive
metallic probe.
Task E2: Develop Sensor Circuitry (Levi)
The Hall Effect sensor determined for the design is the
LEM HO 25-P/SP33 Current Transducer. This sensor has
desirable power requirements that align closely with our
overall system requirements; 3.3 V, while only consuming
25mA, just a fraction of the expected circuit need of 275 mA
to 450 mA [13]. It is important to note that the output of this
sensor is not in terms of current but rather a ratiometric
voltage. What this means is that the output is a ratio of the
CCC current and the input voltage supplied to the sensor.
It was our initial thought that the signal produced by the
Hall Effect sensor could be directly transmitted to the
microcontroller for processing. However, after conducting
preliminary testing with a 1 A CCC, the sensor produced a
100 mV output but the signal was degraded by heavy noise.
We attributed this to the noisy nature of the equipment being
used, specifically the solderless breadboard, and the
environment of the laboratory.
Figure 20. Filtering and Overvoltage Circuitry for Hall Effect Sensor
We implemented two methodologies to reduce the level of
noise: creating the circuit on a prototyping circuit board and
passing the signal through a low pass filter (LPF). This
transition, however, is not our miracle fix and was not
sufficient enough to completely reduce the noise, as the
sensor itself and the environment may be contributing. The
circuit for this application is shown in Fig. 20.
To clean up the signal after reducing all possible noise
inputs, we incorporated a LPF. Upon applying various filters
internal to the oscilloscope, we experimentally determined
that a value of 12 kHz would be sufficient to filter the excess
noise. A screenshot of the nonfiltered signal, filtered signal,
and the input voltage signal can be seen in Fig. 19, by the
top, middle and bottom lines, respectively. This filtered
signal has been acceptable enough for our microcontroller to
measure, however, further refinements can be made to the
microcontroller code, if necessary.
To accomplish this filtering in the physical circuitry, a
simple passive LPF was created using a 13.3 k resistor and
a 1 nF capacitor, creating a cutoff frequency (𝑓𝑐) of
approximately 11.97 kHz, excluding component tolerances.
Though this calculated cutoff frequency is less than the
experimental value, the two values are nearly equivalent and
the difference makes no measurable difference in the quality
of the signal. This cutoff frequency was calculated using
Equation 3 and the rearranged version in Equation 4, where
the capacitance value (C) was arbitrarily picked and the
resistance value (R) was calculated for the 12 kHz frequency.
Figure 21. Commercially Available Voltage Tester X Distance from
Conductor

11. 𝑓𝑐 = 1/(2𝜋𝑅𝐶) (3)
𝑅 = 1/(2𝜋𝑓𝑐 𝐶) (4)
However effective Hall Effect sensors may be in
measuring a power lines current characteristic, the particular
sensor chosen does not meet the criteria of being easily
installed onto a power line as it does not split to clamp around
the line.
Figure 22. Commercially Available Voltage Tester X+X Distance from
Conductor
Figure 23. Voltage Sensor Circuitry
To initially gain a baseline for the output of our desired
voltage measurement method, a simplified series of tests
utilizing the commercially available voltage sensor were
conducted. The sensor was powered, as per the
manufacturer’s specifications and as the conductive metal
plate was static at some X distance relative to a CCC, the
output was measured from the negative terminal of the LED.
This static nature can be seen in Fig. 18 where the output can
be seen as a partial sinusoidal wave, terminated just after the
positive peak. As the metal plate was moved closer to the
CCC, the termination region expanded, producing a more
characteristic positive half wave rectified sinusoidal wave.
This phenomenon can be seen in Fig. 22, where the plate was
some distance X plus X from the CCC.
We had intended to reproduce and modify the circuitry of the
voltage tester to fit our needs but after the initial testing, it
was decided to use a simplified circuit, seen in Fig. 23. This
circuit consists of three NPN Bipolar Junction Transistors
(BJT), three resistors and one LED. On the lower right
corner, the first BJT (Q1) can be seen leading the circuit by
reading the initial voltage value, arbitrarily picked for
display purposes. The output of the first BJT (Q1) is then
inputted to the second BJT (Q2) for amplification, where the
process repeats for the third BJT (Q3). With a theoretical
gain of 1,000,000, this circuit is able to receive a small input
voltage and amplify it to a readable output voltage. In the
physical circuit, when the metallic probe is placed near an
electrically live wire, the LED lights up, signifying the
presence of a voltage. This circuit reduced the PCB footprint
and made it more space friendly than the voltage tester
circuit.
To verify the amplification and operation of this system, the
metallic plate was placed near a power cord of a handheld
power tool, and it produced the output seen in Fig. 24. It is
important to note that the oscilloscope measured the relative
frequency (f) of the power cord or 60 Hz. This revelation was
very important, as it means our system could calculate the
line frequency.
TABLE II
EXPERIMENTAL VS. THEORETICAL POWER BUDGET
Experimental Power Budget Theoretical
Idle Nominal (L) Nominal (H) Nominal
Microcontroller 50 mA 1851
mA 2501
mA 250 mA
Wi-Fi Module 5 mA 70 mA 1701
mA 250 mA
Current 18 mA 18 mA 18 mA 125 mA
Voltage 0.2 mA 0.5 mA 0.5 mA 125 mA
Total 73.2 mA 273.5 mA 438.5 mA 750 mA
Total 0.242 W 0.903 W 1.447 W 2.475 W
1
Value taken from datasheet
Task E3: Develop Software for Additional Characteristic
Calculation (Broc and Levi)
Upon acquiring the conditioned signals from the current
and voltage sensors, the microcontroller completes processes
to display the finite current and voltage values. These
processes utilize sensor baselines anytime the output of
either measurement sensor varies and which helps determine
if disturbances are due to a fault with the line or external
factors.
Quantification of the Hall Effect Sensor arithmetic was
completed through testing with AC and DC currents. As
previously mentioned, see Task C2, the microcontroller can
read and display the output of the Hall Effect sensor,
capturing any changes in the nominal current of the CCC.
From our initial testing, see Fig. 19, the baseline of 100 mV
output for 1 A input has been used to map the sensors
response. Additional tests with an AC line have not occurred

12. but tests using a DC line have further refined our sensor
characterization.
Figure 2417. Voltage Sensor Output 120V Power Cord
On the other hand, determining the arithmetic for the
Voltage sensor has been difficult. The large gain from the
triple NPN circuit seems to be causing troubles as it can read
and amplify static electricity from random objects. As
mentioned in Task C2, the Voltage sensor is currently
working as a digital sensor (ON/OFF) and seems to output
the same voltage regardless of whether it is reading a
powerline or a statically charged object. Additional sensor
testing and signal manipulation will need to be completed to
define the signal baselines.
Task E4: Test Sensor Circuitry (Levi)
Completion of circuit designs and prototyping have been
completed. At this time, testing of the sensor circuitry has
been limited to the results in Fig. 19, Fig. 21, Fig. 22, and
Fig. 24. However, we feel confident with the Hall Effect
sensor circuitry and refined any signal noise internally to the
microcontroller, as it will reduce the number of components
in the PLMU. As mentioned in the previous section, Task E3,
the Voltage sensor is giving unreliable results and baselines
cannot be accurately determined. Refining the output may be
a matter of designing a circuit with less gain, to reduce the
ability to read static electricity, or it may be as simple as
signal manipulation. After compilation of the sensor
baselines testing to verify proper circuit integration
requirements have been experimentally completed (i.e.
properly filtered signals and power requirements).
Objective F: System Integration
Task F1: Integrate Pre-fabricated Modules into Prototype
(Michael)
Module selection has been completed for all subsections
based on the common input voltage requirement of 3.3 V.
Additionally, components were selected on interface
compatibility with the Piccolo microcontroller. The sensors
is communicated through the GPIO ports of the Piccolo, with
the ESP8266 wireless module interfacing with the UART
pins.
The experimentally verified power budget can be seen in
Table II. Two different subsystem states were tested: one
where the subsystem is on but preforming no tasks (idle) and
another where the subsystem in preforming a nominal task
(nominal). The power consumption from each subsystem
was added together to find an experimentally-validated
power budget. This updated power budget was compared
against the theoretical expectations and analyzed for power
saving measures. Despite the microcontroller ability to be
powered from a 3.3 V source, the microcontroller requires a
USB connection to upload the runtime software and offload
the results and thus receiving power through the USB
connection. Therefore, the microcontroller nominal results
are taken from the respective datasheet until an alternative
testing procedure can be determined.
Task F2: Design Final Schematic and PCB Layout (Michael)
All the separate modules have been integrated into one
finalized system design. This does not include the
microcontroller, which due to difficulties in fabrication was
determined to remain a unique module. The process of
merging each modules schematic was completed in Multisim
with PCB layout designs completed in Ultiboard. The design
files were milled into PCBs and fabricated with surface
mount components using on campus equipment. The
completed system PCB is shown below in Fig. 25 with the
ESP8266 WiFi module separated for verification and testing
purposes.
Fig. 25 Finalized System PCB
V. PROJECT MANAGEMENT
The Gantt Chart included in Appendix A outlines the
projected timeframes for each specific task.

13. VI. TESTING PROCEDURE RESULTS
TABLE III
EXPERIMENTAL VS. EXPECTED RESULTS
1 Sampling Rate Microcontroller 25%<X<50% 49.50% B. Friend 2/10/2016
2 Current Acquistion Microcontroller 100 mV per Amp 195 mV at 2A B. Friend 2/20/2016
3 Voltage Acquistion Microcontroller 640 mV 620 mV B. Friend 2/20/2016
4 UART Transmission Microcontroller 3.3 VDC 3.3 VDC B. Friend 3/5/2016
5 Power Consumption Microcontroller 300 mW 250 mW B. Friend 2/20/2016
6 WIFI Webpage Wifi Module
Webpage is succesfully
created and reachable through
a web browser
Successfully
reached and
accessible N. Crocker 2/10/2016
7 WIFI Data Transfer Wifi Module
Display the data being
transferred from the
microcontroller and display
the results
Correct data
was recevied
and displayed
properly N. Crocker 4/18/2016
8 Energy Harvester Opt. Energy Harvester Optimized coil with 20 turns Optimized Coil M. Partridge 11/3/2015
9 Energy Transformer Energy Harvester 5 VPP 1 VPP M. Partridge 3/1/2016
10 Smoothing Cap. Output Power Conditioning.5 s 1 s M. Partridge 2/25/2016
11 Current Sensor Output Current Sensor 100 mV per Amp 95 mV at 1 Amp L. Lewis 2/5/2016
12 Voltage Sensor Output Voltage Sensor 700 mV when voltage is present620 mV L. Lewis 2/5/2016
13 Super Cap. Discharge Power Conditioning M. Wegerson 2/10/2016
A .97 W Draw
0 mA 90 s 44.3 s
250 mA 330 s 157.1 s
500 mA 500 s indefinitely
750 mA 1000 s indefinitely
B 1.77 W
0 mA 50 s 21.5 s
250 mA 70 s 33.3 s
500 mA 300 s indefinitely
750 mA 500 s indefinitely
C 2.58 W
0 mA 30 s 14.3 s
250 mA 45 s 18.6 s
500 mA 60 s 28.4 s
750 mA 200 s 91.4 s
14 System power consumption Entire System M. Wegerson 2/25/2016
A Nominal Power consumption Microcontroller 300 mA 250 mA
B Nominal Power consumption Wifi Module 250 mA 170 mA
C Nominal Power consumption Current Sensor 20 mA 18 mA
D Nominal Power consumption Voltage Sensor 20 mA .5 mA
E Total Power Consumption Entire System 2.475 W 1.447 W
Tested ByTest ID Description Subsection Expected Results Actual Results Date Completed

14. VII. IMPLEMENTATION
The working budget is outlined in Appendix B.
VIII. CONCLUSION
The prototype created is a self-powered device that
utilizes the magnetic flux leakage from the power lines. The
residual leakage is harvested by utilizing a core made of
magnetic material with wire wound in parallel to the
direction of the current carrying conductor. The core
harnesses approximately 5 watts while the device consumes
a calculated 2.5 watts. During situations where the core is
unable to supply sufficient power, the integrated capacitor
back-up is able to power the PLMU for up to 171 seconds.
Testing the Hall Effect sensor, with an input of 1A, produces
a 100mV output, which will serve as the devices current
calculation baseline. The microcontroller has been proven to
sample at 200 kHz and consumes 49% of its computing
capabilities. The controller is currently sampling 3 ADC
channels and the data is converted to characters for
transmitting. Once the measurements are taken, they are
routed back to the control center using a wireless network
constructed from Adafruit HUZZAH ESP8266 wireless
transmitters. One functionality of this wireless mesh
network is the ability to access data at any one node via
Bluetooth, allowing for precise data analysis. At the control
center all the collected data from the wireless mesh network
can be analyzed and monitored for abnormalities.
References
[1] Keunsu Chang, Sungmuk Kang,Kyung Park, Seunghwan Shin,
Hyeong-Seok Kim, and Hoseong Kim. “Electric Field Energy
Harvesting Powered Wireless Sensors for Smart Grid.” Journal of
Electrical Engineering and Technology, Vol 7, No. 1: n. pag. Web 10
Sept. 2015.
[2] Rashed H. Bhuiyan, Rodger A. Dougal, Mohammod Ali. “A Miniature
Energy Harvesting Device for Wireless Sensors in Electric Power
System.” IEEE Sensors Journal, Vol. 10, No. 7 (2010): n. pag. Web.
10 Sept. 2015.
[3] Igor Paprotny, Qiliang Xu, Wai Wha Chan, Richard M. White, and
Paul k. White. “Electromechanical Energy Scavenging from Current
Carrying Conductors.” IEEE Sensors Journal, Vol. 13, No. 1: n. pag.
Web. 9 Sept. 2015.
[4] Nina M. Roscoe and Martin D. Judd “Harvesting Energy from
Magnetic Fields to Power Condition Monitoring Sensors.” IEEE
Sensors Journal, Vol. 13, No. 6: n. pag. Web. 8 Sept. 2015.
[5] Technical Report. Iraina Edwards, Benjamin Josephson, and Karl
Lokken. “Design and Implementation of Self-Powered Power Line
Sensor”.
[6] Frank Kreikebaum, Debrup Das, Yi Yang, Frank Lambert, Deepak
Divan. “Smart Wires-A Distributed, Low-Cost Solution for
Controlling Power Flows and Monitoring Transmission Lines.” IEEE
Sensors Journal, n. pag. Web. 10 Sept. 2015
[7] Moazzam Shamsi, “Wired Versus Wireless Trade-offs”, InTech,
2015.[Online].Available: http://www2.emersonprocess.com/
siteadmincenter/PM%20Articles/48968_ePrints.pdf Web. 17 Sept.
2015
[8] Texas Instruments. (2014, Dec.). “Low Imput Voltage Synchronous
Boost Converter with 1.3-A Switches” [Online]. Available:
http://www.ti.com/lit/ds/symlink/tps61200.pdf. 1 Oct. 2015.
[9] Texas Instruments. (2014, Jan.). “LM117/LM317A/LM317-N Three-
Terminal Adjustable Regulator”. Available:
http://www.ti.com/lit/ds/symlink/lm117.pdf. 2 Oct. 2015.
[10] Expressif Systems OIT Team. (June 1, 2015). “ESP8266EX” [Online].
Available: https://www.adafruit.com/images/product-files/2471/0A-
ESP8266__Datasheet__EN_v4.3.pdf [September 30, 2015].
[11] Adafruit Industries. (June 16, 2015). “Adafruit HUZZAH ESP8266
breakout” [Online]. Available https://learn.adafruit.com/adafruit-
huzzah-esp8266-breakout [October 10, 2015].
[12] ‘TMS320F28069 | Piccolo F2802x/3x/5x/6x/7x | Real-time Control |
Description & parametrics’, Texas Instruments Incorporated, Jul-
2014. [Online]. Available:
http://www.ti.com/product/TMS320F28069. [Accessed: 22-Oct-
2015].
[13] LEM. (2014, Feb. 12). “Current Transducer HO-P/SP33 Series”
[Online]. Available: http://www.lem.com/docs/products/ho-
p_sp33%20series.pdf [Oct. 10, 2015].

15. Appendix A
Gantt Chart Project Planner
Figure 19. Report 2 Gantt Chart
Figure 18. Report 1 Gantt Chart

16. Figure 20. Report 3 Gantt Chart
Figure 29. Final Report Gantt Chart
In the original Gantt chart all that was included was the main objectives and goals. The tasks that were needed to complete
those objectives were not thoroughly laid out, so the biggest change from the Gantt chart between Report 1 and Report 3 was
the inclusion of these tasks. Another thing that can be found in the most recent Gantt chart is the synchronization of the
tasks. The objectives and tasks are in the same order in both the Gantt chart and Report. This allows a viewer to follow the
work completion while reading the report. After every task one can also read which member is working on that specific
section. This was roughly indicated in the first Gantt chart but it is clearly identified in the newest Report. With the
inclusion of tasks, we were able to better estimate the duration of each objective and set more precise deadlines for the group.
The Gantt chart will continue to be updated and edited as new tasks present themselves, but, for now, it accurately displays
the tasks of this project with the contribution from each member.
PLAN PLAN ACTUAL ACTUAL PERCENT
ACTIVITY START DURATION START DURATION COMPLETE Weeks
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Initial Research - Broc, Levi, Matt, Michael, Nathan 2 2 2 3 100%
Objective A: Develop Self-sufficient, Contactless Power System
Task A1: Energy Harvesting Coil - Levi, Matt 2 20 4 22 100%
Task A2: Regulation Circuit Design - Michael 2 21 3 20 100%
Objective B: Basic Wireless Communication
Task B1: Tranceiver Selection - Matt and Nathan 2 5 3 4 100%
Objective C: Communication with Piccolo Microcontroller
Task C1: Communication Using TI Microcontroller - Broc 2 23 3 23 100%
Task C2: Data Collection and Transmission - Broc 2 23 3 23 100%
Objective D: Implementation of Wireless Network
Task D1: Testing Transmitting/Receiving Voltage versus Distance - Matt and Nathan 6 5 10 13 30%
Task D2: Construct Mesh Network - Matt and Nathan 18 12 23 0 5%
Task D3: Mesh Wireless Communication Testing - Matt and Nathan 23 4 0 0 5%
Objective E: Measurement Circuitry
Task E1: Sensor Selection - Levi 2 6 3 4 100%
Task E2: Develop Sensor Circuitry - Levi 15 10 20 10 100%
Task E3: Develop Software for Additional Characteristic Calculation - Broc and Levi 16 10 20 10 80%
Task E4: Test Sensor Circuitry - Levi 20 6 21 5 95%
Objective F: System Integration
Task F1: Integrate Pre-fabricated Modules into Prototype - Michael 7 10 12 5 100%
Task F2: Design Final Schematic and PCB Layout - Michael 18 10 24 6 100%

17. Appendix B
Budget
Table IV. Working Budget
Budget Unit Cost # of
Units
Total Cost
Objective A
Task A1
Components* --- --- $ 20.00
Task A2
Li Power Converter $ 14.95 1 $ 14.95
Super Capacitors $ 10.00 2 $ 20.00
Support Components* --- --- $ 10.00
Objective B
Task B1
ESP8266 $ 9.95 1 $ 9.95
Objective C
TI C2000 F28069
Controller
$ 115.99 1 $ 115.99
Objective D
No Items Needed $ -
Objective E
Task E1
HO25_P/SP33 $ 13.84 2 $ 27.68
Voltage Measurement --- ---
Objective F
Task F2
PCB Fabrication $40 4 $ 160.00
Extended Cost: $ 378.57
Component* - Ongoing calculations needed before final component selection.
Estimation based off previous year or current market value of comparable
components.

18. Appendix C
Minutes from Weekly Meetings with Dr. Arash Nejadpak
(Contactless Power Line Monitoring Unit)
Meeting Minutes 9/3/15
Defined project as no contact/contactless unit
that harvests magnetic energy, measures
voltage, current, and phase angle. Would also
like to incorporate data transmission.
Will determine tasks during next
meeting.
High sampling rate is required to properly
analyze transmission line.
Will research necessary sampling
frequencies for next meeting.
Avoid ZigBee due to previous years’
experience.
Nate - chosen as group leader.
Meeting Minutes 9/10/15
Examined similar device (Kill-A-Watt) for ideas.
It did not incorporate data transmission
and was invasive.
Discussed the finding on high sampling rate.
Determined outside scope of prototype
to use minimum of 2x line frequency =
120 Hz
Determined initial tasks.
Wireless – Nate and Matt
PCB Design – Michael
Calculations/Microcontroller – Broc
Measurement Design – Levi
Meeting Minutes 9/17/15
Analyzed TI Piccolo Microcontroller.
Will use this microcontroller for
prototype.
Determined that modules will be better than
individual components.
Meeting Minutes 9/30/15
Module Search:
Levi- Looked at the old design but
currently has not yet found suitable
replacement.
Nathan and Matt - Looked at Micaz
MPR2400 Wifi module, specifications
looked good but price has yet to be
determined.
Michael - ESP8266 for Wifi module,
potential option. Nathan/Matt looked at
product, concerned over overcurrent
issue.
Broc - Unable to attend meeting due to
last minute change in meeting time.
Potential sensors: Hall-Effect for
current/voltage sensing (Ex. Honeywell,
Pearson Current Sensors)
Power Supply Unit:
Previous years design used equipment
and components not calibrated for low
voltage settings and failed to achieve self-
sufficient power from magnetic field.
Design can be followed but must be
calibrated for 120V and expect 10A
current.
System Level Designs:
First prototype should focus on nominal
conditions -> 120V at a 200Hz sampling
rate. First iteration will not sample for
anomalous situations.
Use Zener and Diodes as clamps for ADC
voltage protection.
Due to time conflicts with members on
Wednesdays at 5pm, meeting will be moved to
Monday at 4:30.
Meeting Minutes 10/5/15
Michael: Will design power rectifying and
conditioning system. Arash will provide
schematic for harvester unit
Nathan / Matt: Determined that ESP8266 will
be the WiFi module that will be used for the
project. Will be ordered by next week.
Levi: Potential Hall-effect sensor (Honeywell
CSLA1DJ). Pin Description and application
notes still need for final determination
Priced at $30 from Digikey, available at
Mouser for slightly less.
Broc: Worked on Piccolo software
familiarization and contacted TI Technical

19. Support concerning issues with hardware and
software issues.
Will be in town this upcoming weekend,
Nathan and Broc will collaborate on base
software design.
Monday at 4:30 works as a meeting time for
everyone, will be the new meeting time for
next week.
Meeting Minutes 10/12/15
Levi: Continued to look for Hall Effect Sensors.
Leaning towards brand LEM.
Current Potential Options: LTSR 6-NP ->
Suggested by Arash (Vcc +5V)
HO-P/SP33 ->
Fits system
design (VCC
+3.3V)
Power System:
Levi / Broc: Will calculate theoretical
values and design coils and rectifier.
Michael: Conditioning system.
Nathan / Matt: Separate meeting on ESP8266.
Ordered module, will arrive 3-10 days.
Meeting Minutes 10/19/15
Nate / Matt: Testing of ESP8266. Working
with Broc to integrate with microcontroller.
Levi: Hall-Effect sensor was ordered and
arrived, testing with Arash during the upcoming
week.
Michael: Purchase approval for boost
converter and super capacitors.
Broc: Search for alternative for Piccolo.
Meeting Minutes 10/26/15
Create 5 minute presentation PowerPoint for
Minnkota visit tomorrow.
Testing continue with sensors, wireless
transmission, and power conversion.
Meeting Minutes 11/2/15
Collaborate with other senior design project
to share testing data.
Renew license for magnetic harvester
modeling software.
Test transmission of data, report findings to
Arash in 2 weeks.
Meeting Minutes 2/8/16
Levi: Voltage Sensor outputs less than 1V @
2mm separation. Larger distances will be
tested. Current Sensors outputs around 1V
Crocker: Looking at Source Code from Ethan,
working towards a function solution
Matt: Will design LC filter after rectifier for
30Hz -> will smooth out DC input
Meeting Minutes 2/22/16
Crocker/ Broc: Interfacing modules
together. Working with other team to
connect to internet.
Levi/ Broc: ADC and sensor testing continues.
Voltage sensing is working. Current sensing is
not. Voltage sensing may be too sensitive.
Matt: LC Filter has been designed, Multisim
and breadboard testing is ongoing.
Michael: Design combined system PCB in
Multisim and Ultiboard. Order parts in the
next week.
Meeting Minutes 4/4/16
Broc and Nathan: Transmission -> Flaky data
transmission, power flow issues. Sent data,
not expected -> working out the details.
Contracting other team

20. Appendix D
Written Testing Procedures and Results
Microcontroller (Broc):
Microcontroller testing consists of data capturing, and
processing. The initial test to be performed, will be a
sampling test. This test is designed to test varying sampling
frequencies (Hz). The sampling frequency of the controller
will be increased various times while sampling a fixed
analog signal. The test results will yield the total amount of
CPU usage the controller will consume at its highest
sampling frequencies. The result yields at the highest
possible sampling rate, sampling 2 channels at 200 KHz,
the controller consumes 49.5% of its overall usage [1].
The next tests that will be performed will be the testing
of the controller’s analog to digital converting (ADC)
channels. The controller has 2 ADC channels programmed,
each converting independent signals. The first signal
sampled and converted is the current sensor. This test
consists mirroring the Hall Effect sensors output using
function generators. Knowing the ratio of the Hall Effect
sensor’s output yields 100 mV is equal to 1 A. The
controller’s testing will consist of varying the peak-peak
voltage (Vpp) and fixing the frequency at 60 Hz. The result
of the testing will yield the changes in Vpp (relating to
changes in amperes.) The scaling and filtering of the input
signal is filtered and scaled via programming with respect
to the microcontroller [2].
The voltage sampling ADC channel will be the last
performed by the controller. This test measures the AC
voltage of an active 120 VAC power-line. The voltage
measurement circuitry outputs a square wave to the ADC
channel; collecting and processing this wave will test the
ADC channel. The scaling from the voltage sensor equates
to 640 mV is equal to 120 VAC at a fixed distance. The
corresponding square wave has a frequency of 60 Hz. The
voltage-sensing channel of the ADC will both convert the
voltage and frequency inputted to it, to usable data.
Current testing yield dilemmas with the signal, the signal
tends to act more as a digital signal and only records
whether the line is active or not. The voltage sensor is
sensitive to static electricity in its surrounding making the
sampling and data acquisition only a digital on-off value
[3].
Data transmission test is currently set up using GPO
pins that transmit a carrier signal. To test this portion of the
project, a simple 1 load is attached to the transmitting pin
(mimicking the Wi-Fi module.) The test determines
whether the controller is sending data in the form of a
current and voltage signal. The signal is a continuous and
varying signal. Varying input data to the UART
transmission program yields a varying output signal
measured over the resistive (WIFI) load [4].
The last test preformed on the controller is overall
power consumption at idle, low and heavy power
applications. The test involves running the controller as a
standalone device and run a low and heavy consumption
application. For the idle condition the controller was
powered with an independent source at 3.3 VDC. The load
was determined by measuring the current being consumed
by the controller. The low load test involved running a
generic, low consumption program. The load measurement
was determined using the same setup as the idle condition.
Lastly the heavy load consumption test involved measuring
the current consumed by running a heavy application. A
high sampling rate program was used (200 KHz.)
Unfortunately, the program was built using debugging
systems, so the controller could not be unplugged from the
host computer. Using a spliced USB cable, measurement
of the current consumption was completed [5].
Wireless Communications (Nathan & Matt)
First the WiFi microcontroller test is to make sure that
data that would be received would be done so accurately
and communicated properly. Without a display the first
step is to create webpage than can communicate if the
wireless antenna can reach a webpage and display its
contents. Code was written specifically to communicate
over a serial line if the webpage was successfully reached.
This outcome of this was that the network could be reached
and that the chip was able to reach the internet [6].
Following that is a test of the input of another signal
would be interpreted properly. This is done by receiving
and input from a GPI pin that receives a high or low value.
This value is displayed through the serial communications
port and was able to relay the state of the pin in a timely
manner [7].
Energy Power Harvester (Levi & Matt)
Testing regarding the Energy Harvester Coil is
currently limited. Numerous harvesting coils have been
simulated utilizing Infolytica MagNet, an electromagnetic
field simulation software, resulting in a more than
sufficient coil design. However, due to lack of resources,
time, and to further advance the proof of concept, a
traditional transformer has been created. This transformer
will be used to provide the conditioning system with a
signal mimicking that of the harvester coil [8].
The first test of the transformer was with a circular ring
core. This test yielded results with a lot of core saturation
which required a change in the core design. To facilitate a
better signal, the core was changed from the solid ring core
to a bobbin style core, which allowed for controllability of
the core air gap. It is important to be able to vary the air
gap of the core to refine the cores parameters and reduce
the magnetic flux saturation. The next tests done with the
magnetic core is varying the number of windings of the

21. primary and secondary wires. The primary being the input
wires and the secondary being the output wires. Due to the
lack of wire selection, testing has been limited to a limited
number of iterations. The final iteration tested offered the
best results, with a 1:2 turn ratio, primary to secondary.
However, the output voltage at a perfectly sinusoidal
waveform is roughly 1 Vpp, which could cause problems
for the Rectifying and Conditioning circuitry. Future
iterations and tests will be testing the output with smaller
diameter wires and larger diameter bobbin cores, allowing
more turns [9].
Smoothing Capacitor (Michael & Matt)
Once the AC signal goes through the full wave Schottky
diode it will be a full wave signal. We need to make it a DC
signal, so testing was originally done using a LC filter, but
after initial tests it was found that the inductor was not
needed and that just using a capacitor to smooth the signal
was sufficient. So initial testing was done on Multisim
testing different sized capacitors. We started with small
capacitors and then started increasing the size until the full
wave signal smoothed out. With capacitor testing a 220uF
capacitor was picked because of results via Multisim. The
next testing will be run these tests on a bread board. Then
to also test to see if the 5F super capacitors that are already
incorporated in our project as our batteries can also serve
as a smoothing capacitor. This will save on components
and space [10].
Measurement Circuitry (Levi)
Measurement Circuitry testing has been focused on
providing reliable signals to the microcontroller. The first
set of tests to be performed will be done by placing the Hall
Effect sensor on a live power line, both AC and DC. The
intent is to run a predetermined current through the sensor
to record the output voltage. This process will be repeated
a number of times, with varying input currents to determine
the sensor baselines. It was found that when measuring a 1
A, AC power line, the output of the sensor is roughly 100
mV but the signal was degraded by heavy noise. We
implemented two methodologies to reduce the level of
noise: creating the circuit on a prototyping circuit board
and passing the signal through a low pass filter (LPF) with
a cutoff frequency of approximately 12 kHz. This updated
circuit was then testing on a DC power line and we were
able to refine the microcontroller programming, while
testing, to make the microcontroller output representative
of the power line current. We feel confident with the Hall
Effect sensor circuitry and will be further refining the
signal internally to the microcontroller as needed [11].
The second set of tests to be performed will be placing
the Voltage sensor some static distance X from a live
power line and determine the output. This test will be
repeated for additional X plus X distance from the line,
noting the difference in the output. When determining the
initial static reading, the sensor provided a clear signal to
the oscilloscope. It was seen that when placing the sensor
near a power cord for a handheld power tool, it produced
roughly 640 mVpp output voltage. However, when
additional testing occurred, difficulties arose. Due to the
circuit design, the sensor is very sensitive and can read
static electricity. As previously mentioned, this is causing
the sensor to act as a digital sensor and instead of
identifying what the line voltage is, it is essentially saying
whether it can detect voltage or not [12].
Power Conditioning (Michael)
Testing has begun on the power conditioning module.
Capacitor voltage discharge response has been recorded at
varying input currents and output loads. This is
representative of the system response at a time when the
magnetic harvester would be unable to supply sufficient
power to the system. Output loads were selected to reflect
different system states such as solely powering the
microcontroller, both the microcontroller and the wireless
communication powered, and finally a maximum
theoretical power usage. The following power values are
representative of the aforementioned system states: 0.97W,
1.77W, and 2.58W, respectively.
In order to simulate the varying power input from the
energy harvesting coil, a power supply was used to output
+5V and limit the input current at four levels: 0mA,
250mA, 500mA, and 750mA. This power supply was
connected to the input terminals of the power conditioning
circuit. Additionally, half watt 27Ω resistors in groups of
two, four, and six were used to simulate these output power
states listed above. An LED was also attached to the output
as a visual indicator that the output circuit was functioning.
Oscilloscopes to measure the voltage and amp meters to
measure the current were connected to the input and output
terminals of the power conditioning circuits to capture
those characteristics [13].
Testing began with fully charging the capacitor bank.
Then the input current was limited to one of the above four
levels and the output terminals connected to either two,
four, six, or zero resistors (only LED connected). The input
and output voltage and current were measured with respect
time and recorded. This process was repeated at the
remaining three limited input conditions.
Testing of the capacitor voltage discharge response also
experimentally confirmed the theoretical maximum output
current at a given input voltage provided in the TPS61200
datasheet. To experimentally confirm the expected values,
the input and output voltage will be monitored during the
three discharge conditions above. At the time when the
output voltage drops below in the regulated value, the input
voltage will be recorded. This input voltage will then be
compared to the theoretical value in the datasheet to check
for variation.
Testing of the total power usage of system will consist
of measuring the input power characteristics of each
individual subsystem. Two different subsystem states will

22. be tested: one where the subsystem is on but preforming no
tasks (idle) and another where the subsystem in preforming
a nominal task (nominal). The power consumption from
each subsystem will be added together to find an
experimentally-validated power budget. This updated
power budget will then be compared against the theoretical
expectations and analyzed for power saving measures [14].