Abstract: helping to circumstances beyond ones control., power through

Abstract: With the advancements in the medical field, it is easy to
treat numerous diseases and study various micro organisms and produce life
saving drugs that did not exist few decades back. However, we do not have
enough apparatus that is simple and user-friendly to analyze or make
assessments to determine the psychological conditions of a patient. The
treatment given to the patient is affected by the person’s psychological state
of mind in terms of stress or emotional levels. A person’s stress levels are
basically determined by the emotional response and in turn the electrical
impulses generated through the exchange of Sodium and potassium ions at the
Cell Wall of the Human Body which is generally maintained at -70mV. The
electrical impulses can be captured at the Heart or Brain or both in order to
analyze the state of the response of a patient receiving any particular
treatment. In our prototype we register the pulse rate using a heartbeat sensor
and graph it at certain intervals of time. The slope joining the peaks of
consecutive readings indicates the increase/decrease of the patients stress or
responsiveness to the treatment.


Key words:
Arduino microcontroller, Mat lab, Stress, Pulse
Rate sensors.

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II. Introduction:


The prototype can be used basically at the causality or
emergency centers at the hospitals. A person’s responsiveness to a particular
treatment depends on his/her vitals, i.e., blood pressure, heart beat strength,
respiration and also their psychological state which depends on stress and
emotions .The developed product aims at analyzing the stress and emotional
levels based on a pulse sensor and thus provide a parameter for the doctors to
judge the responsiveness of the patient to the treatment. It can also be used
and the process of lie detection, treatment for psychological depressions or
disorders etc.

On further development of the prototype which adds
analyzing of brain signals specially the alpha signals of the brain makes it
more accurate and also reduces the cost and complexity in the existing
ECG(Electro Cardio Gram) and EEG(Electro-Encephalogram). With proper data
processing both the signals can be studied combined or separately.

Stress is your physical or
mental response to certain situations. It can affect you bodily and intellectual
 conditions, and your behavior. A person  responds to stress by producing chemicals and
hormones to help you rise to the challenge. Heart beat increases, brain becomes
work faster , and have a sudden change in energy or burst of energy. This
response fundamental and wholesome and is what kept our ancestors from falling
victim to hungry predators. But too much stress can have harmful effects. Not
all stress is bad. In general,  some
stress deepen your senses, helping to circumstances beyond ones control., power
through unexpected deadlines, or stay clear-minded in chaotic situations. This
is the “fight-or-flight” response that your body triggers in times of
duress. But stress is meant to be temporary. Your body should return to a
natural state after the situation has passed. Your heart rate is calm down,
your limb or muscle to become less rigid, and your respire should return to
normal. The pressures and demands of modern life may put your body in a
heightened state for a long period of time, making your heart pump hard and
your blood vessels constrict for longer than your body can handle. Over time,
these physiological demands can take a roll on your body.


3 types of stress:




stress is the most common type of stress. It’s your body’s immediate reaction
to a new challenge, event, or demand, and it triggers your fight-or-flight
response. As the pressures of a near-miss automobile accident, an argument with
a family member, or a costly mistake at work sink in, your body turns on this
biological response.


acute stress such as stress suffered as the victim of a crime or
life-threatening situation can lead to mental health problems, such as
post-traumatic stress disorder or acute stress disorder.



Acute Stress


acute stress happens frequently, it’s called episodic acute stress. People who
always seem to be having a crisis tend to have episodic acute stress. They are
often short-tempered, irritable, and anxious. People who are “worry warts” or
pessimistic or who tend to see the negative side of everything also tend to
have episodic acute stress.


health effects are persistent in people with episodic acute stress. It may be
hard for people with this type of stress to change their lifestyle, as they
accept stress as a part of life.




acute stress isn’t resolved and begins to increase or lasts for long periods of
time, it becomes chronic stress. This stress is constant and doesn’t go away.


stress can be detrimental to your health, as it can contribute to several
serious diseases or health risks, such as:

heart disease


lung disease


cirrhosis of the



It is
your body instantaneous response to a new provocation, event or demand. and it
triggers your fight-or-flight response. Anxiety stress such as stress suffered
as the victim of a crime or life-aggressive situation can lead to mental disorders
of patient, such as stress syndrome or anxiety stress disorder.


In addition, stressful perception , like worry and anxiety that
are compounded over time, contribute to problems like chest pain, arthritis,
headache, high blood pressure, and heart disease. Stress plays a clear role in
decreasing the ability of an organism to resist a particular infection or toxin
by  the action of specific antibodies or
sensitized white blood cells because  you
are on high alert. Spiritual responses stress include some of the following:
Anxiety and depression symptoms.

and outbursts or rage.

inability to focus.

socially and forgetfulness.

irritability and restlessness

stress includes the problems that occur in the body, such as aches, pains and disease
that develop due to stress. It also includes the responses to those symptoms,
such as self-medicating with sugar or caffeine during times of stress. Some of
the physical symptoms of stress include:

problems such as pain, heart palpitations, and heart disease

Aches and pains
in the body, including headache, back pains, and upset stomach
Problems with
sleep, such as waking up in the night and not being able to fall back
High blood

symptoms include a sense of numbing or detachment from emotional reactions, a
sense of physical detachment, such as seeing oneself from another perspective,
decreased awareness of one’s surroundings, the perception that one’s
environment is unreal or dreamlike, and the inability to recall critical
aspects of the traumatic event (dissociative amnesia).

In addition to the
characteristic dissociative symptoms, ASD shares many of the symptoms with
PTSD(Post-traumatic stress disorder),

the experience or
witnessing of a threatening event that resulted in intense fear or horror

the re-experiencing
of the event by means of flashbacks, recurrent thoughts or dreams, and distress
when reminded of the event

the avoidance of
stimuli that serve as reminders of the event, such as feelings, thoughts,
places, individuals, and activities

anxiety, including
restlessness, difficulty sleeping and concentrating, and hyper vigilance.

a significant
disruption in normal social or work functioning 

Stress is
characterized by specific physiological responses to aversive or noxious

Selye was the first to coin the term “general adaptation syndrome”, to
suggest that stress induced physiological responses proceed through the stages
of alarm, resistance, and exhaustion.

sympathetic branch of the autonomic nervous system gives rise to a specific set
of physiological responses in response to physical or psychological stress. The
body’s response to stress is also termed “fight-or-flight response”, and it is
characterized by an increase in blood flow to skeletal muscles, the heart and
brain, a rise in heart rate and blood pressure, as well as dilation of pupils,
and an increase in the amount of glucose released by the liver.

The onset of
an acute stress response is associated with specific physiological actions in
the sympathetic nervous system, both directly and indirectly through the
release of adrenaline and to a lesser extent nor
adrenaline from the medulla of the adrenal glands. These
catecholamine hormones facilitate immediate physical reactions by triggering
increases in heart rate and breathing, constricting blood vessels. An abundance
of catecholamines at neuro-receptor sites facilitates reliance on spontaneous
or intuitive behaviors often related to combat or escape.

If a stimulus is perceived as a threat, a more intense and
prolonged discharge of the locus cerulean activates the sympathetic division of
the autonomic nervous system (Thase & Howland, 1995). The activation of the
sympathetic nervous system leads to the release of nor epinephrine from
nerve endings acting on the heart, blood vessels, respiratory centers, and
other sites. The ensuing physiological changes constitute a major part of the
acute stress response. The other major player in the acute stress response is
the hypothalamic-pituitary-adrenal axis.


III. Proposed
model- Mental stress testing can be studied from the
cardiovascular changes caused by psychological stress. To examine the effects
of cardiac drugs on mental stress-induced changes, it is useful to attain a
degree of arousal that can be replicated in serial studies which are reliable
to some extent but are not simple and user friendly and also involves complex
processing of the signals generated. Hence, The heartbeat sensor a
modern sensor that could determine the pulse rate based on the light beams
being reflected from the blood vessels and bones. The data from the heartbeat
sensor is given as input to the Arduino Uno an Atmega328 micro controller
interfacing unit which in turn processes it and gives the processed data to Matlab
Software. The Matlab interfaced with the Arduino Uno receives the data through
Arduino and Gives a Pictorial Output from which the stress levels are

The three major parts of solar tracking
system are:

1.       Pulse Rate Sensor

2.       Arduino UNO microcontroller

3.       Matlab




 Block diagram of Stress Analyzer

main components of the proposed system are shown below .

Arduino UNO board-Atmega

Pulse Rate Sensor SEN

Matlab Software


Arduino UNO board-

This microcontroller is on Atmega 328.Arduino has 14 input
output pins in which 8 pins are analog inputs, other 6 pins can be used as PWM
outputs, a power jack, reset button, a 16MHZ crystal oscillator, a USB
connections, an ICSP header. This microcontroller can be simply connected to
the system with the help of USB cable.

For a power source, you
have the option of using the USB or a DC jack. The NCP1117ST50T3G and
the Vin of this regulator is connected via DC jack input through the M7 diode,
the SMD version of the famous 1N4007 diode. This diode provides
reverse-polarity protection.

The output of the 5V
regulator is connected to the rest of 5V net in the circuit and also to
the input of the 3.3V regulator, LP2985-33DBVR. You can access 5V directly
from  the power header 5V pin.

When you use USB as a
power source, and to provide protection for your USB port, there is a PTC
(positive temperature coefficient) fuse (MF-MSMF050-2)
in series with the USBVCC. This provides protection from over current, 500mA.
When an over current limit is reached, the PTC resistance increases a lot.
Resistance decreases after the over current is removed.




MATLAB combines a desktop
environment tuned for iterative analysis and design processes with a programming
language that expresses matrix and array mathematics directly. With
MATLAB software, you can Acquire, measure, and analyze signals from multiple  devices. Prototype, test, and implement DSP algorithms on PCs,
embedded processors, SoCs, and FPGAs.


Embedded System Design, the MATLAB can be used for the following purposes.

fixed-point designs in simulation before implementation.

Automatically generate C/C++ or HDL code for production
and integration into your application.
Incorporate implementation-ready algorithms that
generate optimized C code for ARM®processors and HDL code for

The Arduino Uno is also compatible with the MATLAB in order
to capture, Process, Plot/Stem the values and Analyze the signals generated by
the Arduino or received by the Arduino.

The Interfacing between Arduino and MATLAB can be done from
the following procedure.

Arduino Interface with


going to create simple MATLAB m-files to talk to our Arduino
board. The MATLAB Support Packages for Arduino Hardware lets you use
MATLAB to communicate with your board through USB cable. The support packages
are available for 32-bit and 64-bit Windows, 64-bit Mac OS and 64-bit Linux.


Installing Packages-
You can easily install packages through your

1.       First, start MATLAB and click the Add-Ons drop down
menu. In the drop-down menu click Get Hardware Support Packages. It will start the package installer window.

Select Install from internet and then Next.

2.       In the next window you will see all the available
packages for MATLAB and Simulink. Select the Arduino package, then
check all the packages displayed and click Next to
continue installation. Note that this picture is showing that I am
reinstalling the Arduino packages because I had previously installed them.

3.       Next, the installer will ask you to log in to your
MathWorks account. If you don’t have an account, you can create one during
installation. Accept the license agreement on the next screen and continue to
download the packages. Now you have to wait for MATLAB  to download
and install all the required packages.


Once the packages are
installed, connect your Arduino board to your PC and type the following command
in MATLAB command window,

>> a = arduino()

if you have more than one
Arduino connected to your PC, you have to specify the board type you will
be communicating with:

>> a = arduino(‘com3’, ‘uno’)

MATLAB will then attempt
to communicate with your board. If successful, MATLAB will display the
properties of the Arduino board connected to your PC as shown below:

This information displays
the port on which your board is connected, the model of your Arduino board, and
available pins and libraries available for the board. 

In your workspace, you
will see a variable a, which is the MATLAB Arduino object. Run the
following command to clear this object.

>> clear a

This command will remove
the object a from your workspace.


V. Working-

The prototype working can
be defined on 3 stages.

Pulse rate Sensor SEN-11574

Pulse Rate sensor SEN 11574 is a modern plug-and-play
heart-rate sensor for Arduino. It can be used by students, artists, athletes,
makers, and game & mobile developers who want to easily incorporate live
heart-rate data into their projects.It essentially combines a simple optical heart
rate sensor with amplification and noise cancellation circuitry making it fast
and easy to get reliable pulse readings. Also, it sips power with just 4mA
current draw at 5V so it’s great for mobile applications.

These readings are received by the
Arduino and further classified to bar graph it and implement the manual reading


Ardunio UNO is the most used and document board of the whole Arduino family .
it is a microcontroller board based on At mega 328 P. the Arduino board is the
prototype  acts
as an interface between the Sensor and the MATLAB software.




MATLAB software is used for graphing of the recorded pulse values and bargraph
it as per the instants correspondingly. The MATLAB also provides interfacing
option with the Arduino by installing the respective corresponding packages and
little programming for the Setting of the graph characteristics.

obtained graphs are stemmed plots with discrete value points each at certain
intervals. The difference between any two consecutive points gives the degree
of rate of change of the emotional states which in turn provide a reference to
determine the Response of the patient for the treatment.

will  attempt to communicate with
your board. If successful, MATLAB will display the properties of the
signals processed by your Arduino board. This information displays the on
device which your component  is interfaced
, the model of your Arduino board, and available pins and libraries available
for the board. In your workspace, you will see a variable a, which is the
MATLAB Arduino object.

VI. Results and conclusion:

output graphs given by the prototype gives information for the doctors to
analyze the stress levels and the responsiveness of the patient for the treatment
being given and thus decide the life saving prescription or can also be used if
the person(the Subject) is facing heavy stress responses during the cases of
Psychological disorders or Lie detecting.

mean average slope of the stress elevations and declinations will give us a
perpetuated result of the subject.

VII. References :


1. james W.
Dally & William F. Riley “Experimental StressAnalysisMcGraw-Hill
Publication, 3rd Edition, (1991).

2.  O. Lippold, Physiological Tremor, Scientific
American, Volume 224, Number 3, March 1971.

3. A. Steptoe and M.
Kivimäki, “Stress and cardiovascular disease: an update on current knowledge,”
Annual Review of Public Health, vol. 34, no. 1, pp. 337–354, 2013

4. V. Marmarelis,
“Modeling methology for nonlinear physiological systems,” Annals of Biomedical
Engineering, vol. 25, no. 2, 1997, pp. 239-251.