1. A device that utilizes near-infrared sensors and analog
haptic feedback
Daniel Brown, David Cabral, Charlie Cai, Tony Dallas
BEN 487 Final Capstone Paper
April 28th, 2015
Table of Contents:
________________________________________
2. Introduction

2. 1
4. Background
6. Basic Principles
8. Functional Requirements
10. Constraints
12. Market & Industry Analysis
15. Final Design
18. Budget
20. Competitive Matrix for Original Designs
20. Problems Encountered
23. Testing Protocol & Results
31. Conclusions
32. Future Work / Areas of Improvement
34. References
36. Appendix A: CAD Drawing of thimbles
INTRODUCTION:
The NIRvana Sensing Glove is a medical device that is being developed to
detect changes in tissue density and properties associated with healthy versus
cancerous breast tissue and relay that information to the user via changing vibrational

3. 2
magnitudes. The current prototype is not yet at this point, but is able to act as a pulse
detector that recreates the pulse using analog haptic feedback.
The embodiment of the device is that of a portable glove body constructed with a
near-infrared (NIR) sensor system secured at the distal ends of the index and middle
fingers. Additionally, an Arduino microcontroller is used to analyze and process the data
collected by the sensor and translate it into a vibrational haptic feedback provided by
miniature vibrational motor discs positioned and directed at the palm of the hand.
Historically, NIR has struggled to become a reliable modality for cancer screening and
the ultimate goal is to develop a device that integrates the human sense of touch to
optimize performance. Ideally, the technology on which this device is based could also
be used in a variety of other applications, not limited to the medical field.
Visible light is usually defined as having a wavelength within the range of 400-
700nm. NIR light falls in the region of 700nm to 1,000nm and is invisible to the naked
eye. In medical applications, NIR is used as an optical imaging technique in which it is
directed into a tissue medium and a detector collects data that is used to describe the
interaction between the matter and the emitted light. In biologic applications, absorption
from different tissue constituents plays an important role in determining how much light
is absorbed after a certain depth [12]. Near-infrared light is able to penetrate biological
tissues more efficiently compared to visible light because these tissues scatter and
absorb less light at longer wavelengths. In addition, water and most naturally occurring
fluorescent chemical compounds do not absorb substantial amounts of energy within
the near-infrared region; however, at wavelengths exceeding 950nm, imaging
capabilities diminish due to increased absorption by water and lipids. Studies have

4. 3
shown that a clear window for live imaging of biological tissues exists at wavelengths
between 650nm and 950nm [11].
(Figure 1: A Visual representation of the entire electromagnetic spectrum. The NIR region ranges from
700nm to 1000nm. NIR waves are slightly longer in wavelength compared to visible light.)
In addition to utilizing an NIR sensor, the NIRvana device also required the
integration of an analog haptic feedback. By definition, haptic feedback refers to the
recreation of the sense of touch and is utilized in many applications to communicate
information to the user through the use of a controlled actuator (the component that
provides the vibrational feedback). Different from a simple vibrational alert, haptic
feedback uses vibrations to communicate with the user by utilizing a variety of
advanced patterns in order to convey information [9]. In addition to conveying
information, haptic feedback is advantageous because it is discrete and more intuitive.
The premise surrounding the use of analog haptic feedback for our system is based on
the belief that humans are able to better interpret the changing feel of the NIR signal
better than the traditional binary yes/no automated detection. Convenience also plays a
factor because the user is able to feel a haptic response at any angle and an LED
display of numeric data can sometimes be limited depending on the position of the

5. 4
glove during an examination. With regards to performing a self-breast examination,
certain angles would make it extremely difficult for a user to read an LED display.
BACKGROUND:
Palpation is an important part of a physical examination in which a specific part of
the patient’s body is felt by the hands of a trained healthcare practitioner. Palpation is
useful in breast tissue examinations and detecting cancerous masses or “lumps” in the
breast. Screening and early detection of breast cancer before symptoms arise are of
critical importance in combating the disease. Breast cancer that is found due to
symptoms such as swelling, skin irritation, and pain tend to be large and more likely to
have spread to other parts of the breast. The size of the breast cancer and how far it
has spread are amongst the most important factors in predicting the prognosis of a
patient with the disease [4]. Earlier detection of smaller, more confined breast cancer
improves the chances of successful treatments and most doctors believe that early
detection tests save thousands of lives annually [8]. However, current clinical cancer
screening techniques are resource intensive and oftentimes require individuals with
specific training and skills, that lack in smaller hospitals and developing countries.
Additionally, traditional screening techniques can be painful and unsettling to the
patient. Mammography techniques involve compressing the breast tissue between two
clear plates and taking X-ray photographs. Breast tissue must be flattened due to issues
in penetration depth of X-rays [10].
The initial goal of this project was to create a medical device that utilizes NIR
sensors and haptic feedback that is capable of detecting breast tumors based on
physiological differences in tissue density and optical properties; however, the use of

6. 5
this device could fit a wide range of applications not limited to the medical field. With
further modification, this system could be used to detect different types of underlying
cancers such as testicular and skin cancer. Currently, the system operates as a pulse
oximeter that recreates the feeling of the pulse onto to user’s palm based on the
changing absorption of NIR by hemoglobin in the blood. A doctor could touch a patient
anywhere on their body and detect a pulse, perhaps checking the circulation to an
organ during surgery or a reattached arm post-op. Also, a veterinarian could monitor
the pulse of a dog while doing an exam, paying attention to any sudden pulse jumps
caused by pain. Both are very useful applications of the Sensing Glove and more user-
friendly than a stethoscope.
The end goal is for the NIRvana Sensing Glove to be utilized as either an at-
home self-examination tool or a device that assists a professional medical practitioner in
diagnosing different types of breast cancer. This device would be low-cost, easy to use,
sensitive and specific to potentially harmful tissues. This system would be capable of
detecting lumps or masses underlying the skin and used as an indicator that there may
be an abnormality that needs to be further examined.
BASIC PRINCIPLES:
A majority component of tissue is that of the extracellular matrix and water. In
terms of diseased tissue, tumorous tissue sites tend to develop complex networks of
vasculature at the borders that results in higher levels of light attenuation due to
increased blood flow at these sites. Also, tumorous tissue sites tend to be denser than
healthy tissue, which causes light to be scattered at a higher degree [7,12].

7. 6
Based on the principles listed above, the NIR sensor utilizes an 880nm NIR LED
emitter and a silicon phototransistor detector. The LED directs light into a medium and
the phototransistor detects the returning light. As the emitted light travels through the
medium, the emitted photons will interact with a number of absorbing and scattering
components that will affect the amount of light that is able to reach the detector, in this
case the phototransistor. Thus, the sensor is able to detect small changes in NIR
absorption determined by the medium’s properties and quantify these changes as a
voltage signal.
(Figure 2: The image on the left is a cross-sectional display of the characteristic "banana-shaped" path
that NIR will generally travel through tissue. The second image on the right is a simple illustration of
emitted photons interacting with an absorbing structure and traveling through a scattering medium. Less
light reaches the detector than initially emitted.)
The phototransistor can be thought of as a variable resistor that changes
resistance based on the amount of light that it detects. The more light that it detects, the
lower the resistance and vice versa. This variable resistor is placed within a voltage
divider that produces an output voltage depending on the resistance value of
phototransistor. Theoretically, if tumorous tissue has physiological properties that
provide higher degrees of light scatter and attenuation compared to healthy tissue; less
of the emitted light should reach the phototransistor providing a high resistance value
and a higher voltage signal. This principle is further discussed in the testing protocol
section.

8. 7
(Figure 3: Schematic of the phototransistor circuitry, a simple voltage divider, and voltage divider equation
used to calculate the voltage output. The phototransistor acts as a variable Z2 value and Z1 and Vin are
constant values of 22KΩ and 5V, respectively. According to the voltage divider equation, as the Z2
phototransistor value increases, Vout also increases. The phototransistor produces larger Z2 values when
less light is detected.)
FUNCTIONAL REQUIREMENTS:
Specific functional requirements must be addressed when designing a medical
device to ensure the parameters of the hardware being utilized will not only be safe to
use, but electrically efficient as well. A list of the components used in this system is
displayed below:
· Arduino Starting Kit (1)
· Protoshield Kit (1)
· 3D Printed Thimbles (2)
· Black Stretch Fit Glove (1)
· Haptic Vibrational Motors (3)
· IR Emitter – 880nm (1)
· 9V Lithium Battery (1)
· IR Photodetector: 380-1180nm (1)
· Resistors: 100k (2), 10k (1), 4.7k (1), 22k (1), 39 (1)

9. 8
· Capacitors: 2.2 μF (1), 68 nF (1)
· Operational Amplifier – LM358 (1)
· Diodes: 1N1418 (2)
The Arduino Uno microcontroller used in this prototype has 14 digital input/output
pins and 6 analog input pins located on the lateral ends of the board. This component
has a 5-volt operating voltage and 40mA DC current output per pin. The Arduino Uno
also has a 32KB memory, which was more than enough space for the prototype’s C++
code [2].
A nine-volt battery source was chosen for this design to separate this product
from other pulse oximeters on the market. Since most pulse oximeters require a finger
clip along with a large machine and a visual display, the system cannot be used outside
of the clinical environment. Utilizing a mobile power source ultimately provides this
prototype the capability to be used anywhere, at any time.
Because the design of the prototype demanded for the LED and photodetector to
be on the underside of the distal ends of index and middle finger respectively, a housing
system had to be developed in order to keep these components fixed to the glove.
Using Solidworks software, a three-dimensional image was created that modeled the
configuration of a thimble. The thimble was then cut in half along the horizontal axis
and a hole was made on the underside of the thimble allowing for a modular fit for the
LED and photodetector. Once the drawing was completed, the file was converted to
.STL and sent to the 3D printing lab. After a short period of time, two plastic thimbles
were constructed that fit the exact dimensions of the LED and photodetector.
Aside from the electrical components used in this prototype, the Arduino
algorithm that was created for the device to run was made open-source and public

10. 9
domain. The NIRvana group also updated a tri-weekly blog, recording their progress
throughout the Fall 2014 and Spring 2015 semesters. This blog can be viewed on the
Daring Development Blog section at www.daringrandd.com. In addition to a written
overview of the process, a video was uploaded to YouTube depicting the signal
recognition and haptic feedback early in the prototype development that demonstrates
the detection capability and the analog haptic feedback associated with pulse detection.
To see the early developmental stage of the Sensing Glove, visit
www.youtube.com/watch?v=jIJPxXgGUOo.
CONSTRAINTS:
The original problem statement delivered by the client was to develop a near-
infrared sensor with analog haptic feedback. In other words, the user of the product
should have the ability to “feel” inside of tissue. Instead of using a typical binary yes/no
output, the NIR signal will give the user the ability to feel the change in signal, therefore
essentially feeling one’s pulse. For this prototype, vibrational motors were placed on the
palm of the glove and activated when an individual’s pulse was detected. This output is
completely user specific – only the individual wearing the glove can detect any type of
signal relaying from the sensor. This factor of the design is advantageous to the user
because often times when a patient can see his or her heart rate on an LED monitor,
he/she may feel uncomfortable or nervous and therefore altering the signal being
collected.

11. 10
In addition to being fully user-specific, the size and weight parameters of the
glove were also taken into consideration. For the purposes of this prototype, one
specific glove size (large) was used to act as a mount for the electrical components on
the dorsal surface. If this prototype eventually reached a point of production, multiple
sizes must be created to extend the availability of this product to a larger population.
Along with the glove size, the wire length extending from the protoboard to the LED
components at the fingertips had to be long enough to allow for full finger contraction.
This factor affected the aesthetic value of the prototype since the wires could not be
smoothly aligned across the backside of the fingers and concealed.
Ambient light was a major constraint that greatly affected the quality of the
collected signal. The black 3D printed thimbles that housed the LED and photodetector
sheltered the components from random light in the environment, yet did not fully focus
the beam of light directly into the skin. Additional modifications must be made to the
emitter and the thimbles in order to create a more concentrated beam of emitted
infrared light.
Depth of tissue penetration was a design parameter that was difficult to measure.
The most clear and consistent signal collected by the photodetector was at the very end
of the index fingertip. Because the tissue at this location is very thin and has an
abundance of capillaries, the infrared light penetrated the skin and was collected quite
easily. As the user traveled in the proximal direction to the centerline of the patient, the
vibrational output became more inconsistent and random. The wrist provided an
unclear signal for the user, and when tested on deeper tissue locations like the forearm
and shoulder, barely any signal was collected at all.

12. 11
The most difficult parameter faced during the completion of this project was
learning and implementing the C++ programming language. Although the Arduino
microcontroller kit came with a booklet of examples, the ability to develop a code to read
a specific voltage level, convert that level to a value the Arduino recognizes, and then
output that value to a vibrating motor was a reasonably demanding challenge that took
time to overcome.
MARKET & INDUSTRYANALYSIS:
The NIRvana sensing glove has some competition with similar products currently
going through the FDA approval process. The Glove Tricorder is a device that is similar
the nirvana sensing glove that was developed at the Singularity University of California
in Irvine, California [5]. The glove uses ultrasound to detect tissue stiffness which is
attributed to breast tumors. The Glove Tricorder uses force, temperature, pressure and
vibration sensors on the distal ends of the thumb, index, and middle fingers and the
palm to provide an overall assessment of tissue health. The glove collects the data and
sends it to a computer for analysis by medical professionals. The glove uses vibration
buzzers to alert the medical professional if he or she is applying too much pressure. The
NIR sensors of the NIRvana glove only collects light data whereas the Glove Tricorder
collects information regarding temperature, vibration, pressure and force. Also the
NIRvana sensing glove does not store the data collected onto a different device, instead
uses haptic feedback to help the patient to determine if a tumor is present. Both
products are capable of being marketed to both medical professionals and ordinary

13. 12
consumers. In an article from the Gizmag.com one of the creators of the glove stated
that “ultimately, the group hopes to develop a consumer version of the Glove Tricorder
that doesn't require a physician for an accurate diagnosis” [5].
(Figures 4 and 5 are pictures of the Glove Tricorder that was mentioned previously both front and back
[1]. )
Post-commercialization, the main advantage of utilizing these types of devices
over other imaging products is the cost efficiency. Many underdeveloped parts of the
world do not possess the resources to afford high-priced medical equipment like MRI or
ultrasound machines. The cost of having a mammogram or ultrasound scan in the U.S.
ranges in the hundreds of dollars. An effective and cost-efficient product used for
assisting in the detection of breast cancer has global market potential. Additionally, in a
fast-paced society, healthcare is moving in a direction that favors portable medical
devices that can offer an instant diagnosis. It reinforces the human desire for instant
gratification and reduces the anxiety and fear associated with the unknown, especially

14. 13
in regards to one’s health. There is a large, untapped market for a portable medical
device that can be purchased by the common consumer and used as an at-home self-
check tool that rivals the effectiveness and accuracy of clinical screening.
The infrascanner 2000 model is another device that uses near infrared as
medium similar to the nirvana sensing glove but instead of locating tumors this device
detect intracranial bleeding or a hematoma. A hematoma is a buildup of blood in the
brain caused by a break in the blood vessels. The break could be the result of an
aneurysm or caused by trauma. Damages in the blood vessel's walls happen frequently
without significant trauma most of the time the body repairs it by activating the clotting
cascade. If the damage is significant enough the body will not be able to repair the
blood vessels and hematoma will continue to expand. If a hematoma goes untreated the
escaped blood can come into contact with surrounding tissue and may cause
inflammation, redness, swelling,significant pain and death. Where there is a buildup of
blood there is an increase in red blood cells that carries hemoglobin. Hemoglobin is a
protein that carries oxygen for the cell. When light is emitted onto blood the hemoglobin
both oxygenated and unoxygenated absorbs the light to a certain extent. The infra-
scanner uses a near infrared light at a certain wavelength to scan the cranium. The
devices shoots near infrared laser light into the cranium reaching the surface of the
brain [3]. The scattered light is then collected by optical detectors which differentiates
between circulated blood and pooled blood, since pooled blood absorbs more light than
circulated blood . The device is set up to scan 8 regions of the brain; the left/right sides
of the frontal, occipital, temporal and parietal lobes [3]. The levels of scatter measured
are the indicators of whether a possible hematoma is there. The device runs on 4 AA

15. 14
batteries, it recharges with a USB charger and has a NiMH battery pack just in case it
can't be recharged. This device is similar to our project in that both projects use near
infrared light as a medium. The data that is collected is also reflective data in both
devices.
In 2013 the U.S. Navy and Marine Corps became the main clients for
infrascanner after approving for use by soldiers [6]. There is a huge demand for portable
medical devices especially in the military, due to the special situations that the job
faces. With this device a combat medic can assess who needs urgent medical
treatment and who doesn’t saving time, resources and lives in the process. This
technology may be used by medical professionals in hospitals and EMTs as first stop
measure before turning to more expensive scans CT scans thus saving money.
Potentially this device could be marketed globally especially in developing countries
where access to CT scan might not exist
FINAL DESIGN:
As a final design, the team has developed a fully functional prototype that allows
the user to detect pulse by feeling an analog vibrational feedback in the palm while
visualizing the signal with a simple LED series. The prototype relays information
regarding pulse detection by recreating the feeling of the pulse at the palm of the glove
in which heart rate is felt rather than visually displayed on an oscillator or LED screen.
The design consist of a black stretch-fit glove made of 95% acrylic and 5%
spandex ensuring that the device comfortably fits most hand sizes and provides shock
protection from any electronic components. At the fingertips, two black thimbles with
precisely positioned holes at the ends were 3D printed for the NIR emitter and the

16. 15
photodetector to fit securely and optimize signal acquisition (CAD drawings of these
thimbles can be found in Appendix A). The team used an NIR LED that emits 880nm
near-infrared light and a silicon phototransistor that detects light with wavelengths
between 380-1180nm. Located on the palm of the device, there are three 10mm
piezoelectric vibrational motors positioned in a triangle formation that actuate the haptic
feedback. These motors run on range of 1.0-5.0v allowing the Arduino board to fully
power and vary the magnitude of the vibrational feedback in response to the changing
NIR signal. The Arduino Uno board is equipped with an ATmega328 microcontroller that
operates on 5.0 volts with an input limit of 6-20 volts. Custom coding can be developed
and uploaded onto the microcontroller - the program developed and used for the final
design can be viewed below in figure 8. The final design powers the Arduino with a 9V
lithium battery, but can also be powered by a USB connection to a computer or an AD
adapter that can be plugged into an outlet.
The Arduino board is sewn on the dorsal part of the hand and extends 68.6 mm
long and 53.4 mm wide weighing about 25 grams. In order to minimize bulkiness, the
circuitry was transferred to a protoshield where each piece was soldered and stacked
directly on top of the Arduino board.

17. 16
(Figure 6. Top view of finaldesign w ith active lights) (Figure 7. Bottom view of finaldesign)
In addition to the vibrational feedback, 5 LED bulbs were installed on the
protoboard signifying the magnitude of signal voltage being detected for a specific
window. Each light corresponds to a given voltage signal threshold; the first threshold
was set to 1.2V and the last threshold was set to 1.6V with intermediate thresholds
evenly spaced between. As the voltage signal exceeds each threshold, a subsequent
LED is illuminated. These thresholds were chosen to display the range of voltage typical
of human pulse as detected by the device. The signal from the photodetector is
collected and then transformed using an affine function programmed into the
microcontroller. The three vibrational motors are then controlled by an analog output
using this transformed signal. Therefore, as the voltage signal increases so does the
magnitude of the vibration feedback.

18. 17
(Figure 8. The custom Arduino program that was developed and used by the microcontroller in the final
design to transform the collected signal and control the haptic feedback)
Lastly, the functionality of the final design did not meet the goal of detecting
differences in tissue density based on light attenuation and scatter, but the team has
achieved the goal of allowing the user to “feel” the unseen pulse with haptic feedback in
the palm of their hand.
BUDGET:
Andrew Darling served as the team client and financier. The team was allotted a
budget of $500.00 for parts and materials upon approval. The team was also able to
acquire some of the electrical components free of cost as gifts from the electrical
engineering laboratory at Syracuse University. The majority of the budget went towards
materials for phantom testing and funding travel expenses to the Northeast Biomedical
Conference at Rensselaer Polytechnic Institute (RPI) in Troy, NY. The actual cost of
materials and components to construct the Sensing Glove was just over $100, not
including the actual prices of the gifts we received. The display below is a detailed

19. 18
report of all expenses covered. The initial goal of designing and developing a cost-
effective system was met
COMPETITIVE MATRIX FOR ORIGINAL DESIGN:
Custom 3D Thimble tip Foam tip

20. 19
Printed tip
Constraints
Filter out noise 4 2 3
Secures LED’s 5 3 2
Fits all sizes 3 2 4
Cost 5 2 4
Total 17 9 13
Scale: 1-5 (5 being the highest grade)
PROBLEMS ENCOUNTERED:
One of the first problems that encountered when the components of the device
were being assembled was that one of the components , the haptic actuator, required a
voltage draw of 120 volts peak-to-peak. The Arduino Uno can only produce a maximum
of 5 DC volts. The high voltage operating range would also render the device relatively
unsafe to operate and pose a major shock risk to the user. In order to correct the
problem, the haptic actuator was replaced with a miniature vibration motor that operated
on a voltage range of 1.0-5.0 volts DC.
Another problem encountered had to do with inconsistent signal acquisition.
When the glove’s pulse oximeter function was being tested it was noticed through the
LED series and LabView displays that unpredictable inconsistencies existed. At times,
the sensor had difficulty picking up any signal at all, while other times the signal was
very representative of the pleth waveform. Also, the voltage range of the acquired signal
varied between the individual being tested and was highly dependent on how firmly the
sensor was pushed into the skin.

21. 20
Noise in the signal also proved to be problematic. One major source of noise was
due to ambient light in the environment that interacted with the photodetector. For this
problem, black foam was used to cover most of the exposed edges of the near-infrared
LED and phototransistor. After applying this simple hardware filter, an improvement in
the signal was immediately noticed, but some noise still remained in the signal. The
device was also found to function better in dimly lit environments. In order to further
improve the signal-to-noise ratio, a software smoothing filter was embedded in the
Arduino code. A running average filter collects a certain number of data points and
averages them producing a smoother output from the signal, reducing the amount of
high frequency noise in the signal. When the device was tested on a team member's
finger, the response from the LEDs was erratic. The reason for the poor result is to due
with the size of the data point being stored and other software related issues. In the
future, a competent filter must be implemented in the Arduino code to clean out the rest
of the noise present in the signal.
Another problem encountered was that the imaging phantoms that were used for
the experiments. These gelatin imaging phantoms have a low shelf life of about 2-3
days. Once the gelatin phantoms have been stored for over 3 days they begin to decay
and begin to lose mechanical integrity. In order to preserve the phantoms they were
drenched them in vegetable oil overnight, after a day of storage they were used in our
experiments. The testing protocols (stated below) for the imaging phantoms were
followed using two types of phantoms with the same size. The first being a phantom that
mimics the fibroglandular tissue with a center consisting of a tumor mimicking phantom.
The second phantom was tumor mimicking phantom as a whole. It was noticed that

22. 21
when the glove scanned both the tumorous and healthy tissue the response was
virtually the same. This problem is most likely due to the circuitry of the device. There is
a low-pass filter that is used in the glove to clean out noise from the device. For this
problem removing the low pass filter all together and rely solely on software/hardware
filters.
For the final design of the glove thimbles were used to hold the near infrared
LEDs and phototransistor in place on the index and middle finger respectively. The
problem was that the thimbles were a poor fit for someone with larger fingers. So in
order to combat this problem a SolidWorks sketch of two thimbles was drawn with
modifications that would accompany people with larger fingers.The sketch was sent to a
3D printer to be printed with a black color so that it doesn’t reflect much light. Since the
glove is stretchable it can fit a range of sizes, with the modified thimbles the whole
device with be able to fit a user of any adult size.
The glove all together is an incredible piece of technology. The final design
however is not aesthetically pleasing and has bulkiness to it. Having the arduino on the
dorsal part of the wrist uncovered is also problem because of the possibility that is could
be exposed to liquids or solid matter and malfunction. In order to successfully and safely
market the product to a medical professional or an ordinary consumer we have to
reduce the bulk of the machine and make it more pleasing by applying some type of
shield for the arduino. The shield must be able to cover the arduino from other
contaminants like liquids and solid waste. The shield would also provide a more
aesthetic look to the device.
TESTING PROTOCOLS AND RESULTS:

23. 22
Purpose:
The purpose of the experiment was to determine if the NIRvana Sensing Glove
was capable of detecting a human pulse based on changes in NIR light attenuation.
Also, the experiment was designed to test if the device was sensitive enough for a user
to feel the changing NIR signal through the haptic feedback.
Background:
The phototransistor used in the system can be thought of as a variable resistor
that changes resistance based on the amount of light that it detects. The less light that it
detects, the higher the resistance and vice versa. This variable resistor is placed within
a voltage divider that produces an output voltage depending on the resistance value of
phototransistor (the less light that the phototransistor detects, the higher the resistance
value, the higher the output signal voltage). The remaining circuitry was intended to filter
and amplify the signal.
Hemoglobin (Hb) is an oxygen transporting protein found in the blood of
vertebrates that is very effective at absorbing NIR light. The developed prototype was
designed to be able to detect pulse by using the NIR sensor to quantifying changes in
light attenuation due to the pulsatile flow of blood. Every time the heart beats, blood
rushes into the space between the emitted light and the phototransistor and expands
the arteries. The hemoglobin in the blood absorbs the NIR light and blocks it from
reaching the phototransistor and the resultant signal voltage increases. When the heart
relaxes and arterial pressure decreases, the arteries deflate and the lower amount of
attenuating hemoglobin blocking the emitted light causes the signal voltage to decrease.
This sinusoid-like signal is known as the Pleth waveform and acts as a representation of

24. 23
the changing arterial pressure associated with a heartbeat and pulse. The frequency of
the signal is indicative of an individual’s pulse.
(Figure 9: A display of a characteristic Pleth waveform reflective of arterial blood flow changes.)
Materials:
● The developed prototype
● DAQ module (USB6211)
● LabView VI panel
Methods:
The prototype was connected to the DAQ module and LabView was used to
create a detailed visual display of the collected signal in addition to the haptic feedback
of the glove. Pulse was collected at three different sites: the index finger, the thumb,
and the wrist. Screenshots of the data were collected at each of these sites and the
user was asked if they could feel a change in the vibrational magnitude that reflected
the changing NIR signal associated with pulsatile blood flow through the arteries.
Essentially, did the vibrating sensation at the palm match the feeling of a steady
heartbeat?
Results & Data:

25. 24
(Figure 10: A visual capture of an 8-second collected window of the raw NIR signal collected at the
INDEX FINGER. The amplitude is in units of voltage (V) and clearly matches the characteristic photopleth
waveform.)
(Figure 11: A visual capture of a 10-second collected window of the raw NIR signal collected at the
THUMB. The amplitude is in units of voltage.)
(Figure 12: A visual capture of a 10 second collected window of the raw NIR signal collected at the
palmar WRIST. Amplitude is in units of voltage.)
Signal Collection Site Level of Noise Able to detect pulse based
on haptic feedback?
Index Finger Very Low Yes

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Thumb Moderate-High Yes
Wrist High No
Figure 13: A table summarizing the level of noise corresponding to each collection site and the user’s
ability to detect a pulse based on the haptic feedback.
Conclusions Drawn:
Based on photopleth principles and the data collected, the pulse detection testing
serves as an outstanding proof of concept experiment. The changing voltage levels are
based on the amount of emitted light that is able to reach the phototransistor after
interacting with flowing blood in the arteries. When less light is able to reach the
detector because arterial pressure is high and more blood is blocking the light, the
voltage signal is high and the resultant vibrational output is also high. When more light
is able to reach the detector, the voltage signal decreases and the vibrational output
also decreases. This same principle of quantifying changes in light attenuation can be
applied to cancerous masses in soft tissue, specifically breast tissue.
As previously stated in the “Basic Principles” section, tumorous breast tissue has
a tendency to develop complex networks of vasculature at the border of the diseased
sites. More vasculature means more blood flow and results in higher light attenuation
compared to healthy tissue that lack such networks. Also, on average, tumorous tissue
is much denser than healthy tissue and provides higher degrees of light scatter – further
decreasing the likelihood of the emitted light will reach the detector. Theoretically, NIR
light directed into diseased tissue will be attenuated and scattered at a much higher
degree than healthy tissue and the difference in light reaching the detector will cause
differences in the resultant voltage signal. This signal is then translated into a vibrational
output in which the magnitude of vibration is representative of the signal. Hence, a user

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should be able to feel the changing density and type of tissue based on this vibrational
magnitude. When the sensor is over denser, diseased tissues with a greater absorption
coefficient, the vibrational output should be noticeably greater in magnitude than when
the sensor is over healthy tissue that is less dense and has a lower absorption
coefficient. If a device can be developed that is able to detect tiny changes in light
attenuation due to the change in blood volume in a peripheral artery during a heart beat,
modifications to the circuitry and hardware should allow for the same device to detect
larger and more apparent changes in light attenuation and scatter provided by healthy
and diseased soft tissue.
Phantom Testing Protocol - can be considered future work
**Due to time constraints, some of this protocol was not completed. Outlined below is
the work that has been completed and the intended protocol. Data and results have
been omitted.
Purpose:
To evaluate the capability and efficacy of the device in detecting changes in
tissue type based on characteristic differences in mechanical and optical properties.
This testing protocol is specific to breast cancer detection and utilizes flat, artificial
tissue samples.
Materials:
● the prototype device
● LabView and DAQ module
● 175 bloom type A porcine gelatin
● Water
● Titanium dioxide (scattering component)
● India ink (absorbing component)
● Vegetable oil

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● Petroleum jelly
● Molds to create healthy and diseased samples
Background:
Phantoms are artificial tissue samples designed to mimic the mechanical and
optical properties of a given tissue. The density and Modulus is determined by differing
ratios of water and pork-derived gelatin. The optical properties of the phantoms are
determined by the concentrations of titanium dioxide and India ink. Titanium dioxide
provides a light scattering component, while India ink provides light absorption.
Intended Methodology:
For this validation experiment, three types of breast tissue were created based
on a recipe and mixing procedure from the Brooksby Group at Dartmouth College [1].
Adipose, glandular, and tumorous tissue samples were created in which the “healthy”
adipose and glandular tissue samples were flat and a 2 cm diameter cylindrical
tumorous sample was embedded in each tissue type. The tumorous samples have the
highest concentration of gelatin, titanium dioxide, and India ink and the lowest
concentration of water. The high gelatin-to-water ratio contributes to the high-density,
high stiffness properties while the high concentrations of titanium dioxide and India ink
contribute to high light scatter and attenuation, respectively. Small cylindrical samples (2
cm in diameter, 2 cm in height) of each tissue type was mechanically tested to ensure
that the mechanical properties of each sample was comparable to that of real tissue.
The stress-strain curves below (Figure 15) display the viscoelastic mechanical
behaviors of adipose, glandular, and tumorous phantom samples.

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The tumorous tissue should provide a different NIR signal than the less dense
healthy tissue. The differences in optical properties between tissues should also provide
further differentiation between the tissue types. As a validation experiment, a user would
be blindfolded and asked to detect cancerous “lumps” in the phantoms based solely on
the haptic feedback. Since “lumps” attenuate and scatter light at a higher degree than
healthy adipose and glandular tissue, the vibrational intensity should increase at the
diseased sites. Additionally, the device would be connected to LabView because a
visual display of the collected signal could help in identifying characteristics of the NIR
signal indicative of diseased tissue - this data is important in software development and
refinement for this specific application.
(Figure 14: A picture of the phantoms created to mimic the mechanical and optical properties of
breast tissue. The lower sample is an adipose sample with an embedded tumor and the top sample is a
glandular sample with an embedded tumor. The white specks are the scattering titanium dioxide and the
gray color is from the absorbing India ink.)

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(Figure 15: Mechanical behaviors of adipose, glandular, and tumorous phantom samples when exposed
to unconfined compression (1mm/min displacement rate) to failure. All samples displayed the predicted
viscoelastic behavior and had Modulus values that were predicted.)
CONCLUSIONS:
Overall, the current prototype that the NIRvana research team has assembled
acts as a pulse oximeter with future hopes of detecting differences in tissue density.
The team has skillfully arrived at a milestone in the project’s timeline and met the
requirements of the original problem statement – to develop an NIR sensor with analog
haptic feedback. While the sensor cannot detect a clear signal in thicker areas of the
body like the shoulder or chest, there is a sharp haptic response when the sensor is
pressed against the fingertips of an individual. The vibrational feedback the user
recognizes at each pulse is an important step in the development process and has
gained the interest and attention of local bioengineering students and professors.

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Although there exists competition in the marketplace for this medical prototype,
the NIRvana Sensing Glove uniquely utilizes near-infrared light in comparison to
ultraviolet and temperature-oriented medical products. The open source, public domain
requirement requested by the project director allows for any scholar or research team to
continue the work initialized by the NIRvana group. Medical devices that are mobile and
require minimal training to use are advantageous to physicians, trainers, professional in
the medical field, as well as the common consumer because the product then becomes
available to novice users outside of a clinical setting. The NIRvana group intends to
continue their research post-graduation in hopes of creating a fully functional,
aesthetically pleasing, at-home product that can assist in accurately detecting tumorous
tissue underlying a variety of soft tissues.
FUTURE WORK / AREAS OF IMPROVEMENT:
There are a few modifications the group can make to enhance the NIRvana
Sensing Glove, both aesthetically and functionally.
One adjustment made to the design of the glove would be to add a holster for the
battery pack at the opening of the glove by the wrist. Currently, the battery must be
tucked inside of the glove to remain from tugging on the microcontroller. By sewing a
pouch on the underside of the glove, the battery can be easily inserted into the
respective position and hide the additional wiring.
A second alteration that would improve the aesthetics of the prototype would be
to utilize conductive thread instead of bulky, large gauge wires to make electrical
connections. Available through the Arduino website, an “easy wearable kit” is available

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for purchase that includes two spools of conductive thread. Known as “soft circuitry,”
these materials can replace the current rigid wiring and lie closely and smoothly along
the top of the fingers on the glove.
In addition to the batter pack and conductive thread, the research group can
replace the current Arduino Uno board with the Arduino Lilypad microcontroller. This
piece of equipment runs very similarly to the Uno but has a few different specifications
that would be advantageous to the Sensing Glove. The Arduino Lilypad is designed to
be washable and textile friendly and has sections surrounding the circuitry that can be
sewn to fabric. According to the Arduino website, the Uno microcontroller weighs about
25g while the Lilypad weighs only 5g [10]. This difference in weight is appealing to the
group when designing the prototype because the glove should be as lightweight as
possible.
Another adjustment that can be made to the NIRvana Sensing Glove is a
modification of the 3D printed thimbles. Although these thimbles fit well on the fingertips
of the glove, the ability for the thimble to property house the LED components has not
been perfected. By thickening the under side of the thimble, only the tip of the emitter
will be exposed to the surroundings, shining the light directly into the skin. Currently,
the LED is fully exposed and to receive a quality signal, one must press the LED into
the skin of the finger being tested. This modification to the printed thimbles may reduce
ambient light noise and improve the haptic response of the glove.

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REFERENCES:
[1] Brooksby, Ben. "Combining near Infrared Tomography and Magnetic Resonance
Imaging to Improve Breast Tissue Chromosphere and Scattering Assessment." Journal
of Biomedical Optics 10.5 (2005): 1-266. Google Scholar. Web. 29 Apr. 2015
[2] "Compare Board Specs." Arduino. N.p., 2015. Web. 28 Apr. 2015.
[3] Coxworth, Ben. "Infrascanner Model 2000 Uses Light to Look for Brain Injuries."
Infrascanner Model 2000 Uses Light to Look for Brain Injuries. N.p., 5 Feb. 2013. Web.
29 Apr. 2015.
[4] Ezra, Elishai and Fransiska Hadiwidjana. Method and Apparatus For Diagnosis.
Augmented Medical Intelligence Labs, assignee. Patent US20140052026 A1. 19 Aug.
2013. Print.
[5] Fincher, Jonathan. "Glove Tricorder Gives a Hands-on Diagnosis." Editorial.
Gizmag. N.p., 30 Aug. 2012. Web. 21 Apr. 2015.

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[6] Freeman, Kate. "The U.S. Military’s Miracle Scanner." Fortune, 29 Mar. 2013. Web.
29 Apr. 2015.
[7] Herranz, Michel, and Alvaro Ruibal. "Optical Imaging in Breast Cancer Diagnosis:
The Next Evolution." Journal of Oncology 2012 (2012): 1-10. PubMed. Web.
[8] "The Importance of Finding Breast Cancer Early." The Importance of Finding Breast
Cancer Early. The American Cancer Society, 4 Sept. 2015. Web. 29 Apr. 2015.
[9] "Introduction to Haptic Feedback." What Is Haptic Feedback? Precision
Microdrives, n.d. Web. 27 Apr. 2015.
[10] "Mammograms." Mammograms. The American Cancer Society, 4 Sept. 2015.
Web. 29 Apr. 2015.
[11] Pogue, Brian W., Steven P. Poplack, Troy O. Mcbride, Wendy A. Wells, K.
Sunshine Osterman, Ulf L. Osterberg, and Keith D. Paulsen. "Quantitative Hemoglobin
Tomography with Diffuse Near-Infrared Spectroscopy: Pilot Results in the Breast1."
Radiology 218.1 (2001): 261-66. Web.
[12] Smith, Andrew M., Michael C. Mancini, and Shuming Nie. "Second Window for in
Vivo Imaging." Nature Nanotechnology. U.S. National Library of Medicine, n.d. Web.
27 Apr. 2015.

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APPENDIX A - CAD DRAWING OF THIMBLES

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