Week 9 - Research on the Internet Enabled Microcontroller

As salam..

Regarding on the post last week..

Since the plethysmograph still in the same result.

I had met my supervisor, Sir Zul and informed him

the problem that I faced. 

He suggested for me to buy the exactly type 

of sensor that shown in the schematic circuit.

There are SFH 487 for IR and 

SFH 309 FR for photodetector. Currently I'm

already had the SFH 487. Just need to make an 

order for SFH 309 FR. For me to wait the delivery 

might takes few days.

I'm proceed to find out the "Remote System" part in

my project, whether by applied the internet or wireless.

Refer on my proposal for the last FYP Semester 1,

I had found the ioBridge IO-204 was quite 

compatible to act as a remote. This IO-204 is applied

by connecting to a Local Area Networking (LAN) using 

10/100/1000 Base-T-Ethernet and then establishes and 

encrypted connections to ioBridge web server.

But unfortunately, this module not sold in Malaysia.

Even, I buy this module at the out of country, if any 

problems come it might difficult for me to be refer of.

Then, this module also used the internet cable, and 

the price is quite high because plus with the shipping.

Other thing, I'm thinking when the time I want to 

present my project, where can I plug in the internet cable.

From the few matters, I have to decide to find other 

module that might be solve the matters and most important 

is compatible with my "Remote System". 

So, I've found a few modules that related with Arduino

and mostly I found is better to be used 

a wireless application. The Arduino also has the 

Wifi Shield Arduino but in Malaysia still not listed in 

market. 

Then I found DF Robot. Mostly the module from 

DF Robot is related with Arduino.

So, by doing the survey with comparing the price

and the features. I've decided 

to choose Wifi Shield V2.2 for Arduino. 

Below are some pictures of modules that I found:

Wifi Shield Arduino (prefer to use this)

Wifi Shield V2.2 (final choose)

The reason I'm chosen this Wifi Shield V2.2:

(a)   This product is listed in Malaysia market.

(b)   Easy for me to refer if has any problem with this module.

(c)   It's related with Arduino

(d)   This provide the documentation how to set up and the tutorial.

I'm already make an order and waiting for the delivery.

Week 8 - Testing Plethysmograph circuit

As salam..

This post is continued from the previous post.
The research on the Plethysmograph is helped
for me to test the circuit that shown in the schematic
below:

Pulse Plethysmograph Amplifier Circuit

Sensor

The sensor consists of a light source and photodetector.

Whereby the light is shone through the tissues and 

variation in blood volume alters the amount of light falling 

on the detector. The light source and detector can be 

mounted side by side to look at changes in reflected light 

or on either side of a finger or earlobe to detect changed 

in transmitted light. The infrared filter of the phototransistor 

reduces interference from fluorescent lights, which have a 

large AC component in their output.

Amplifier

The amplifier uses an LM358 dual op-amp to provide two 

identical broadly-tuned band pass stages with gains of 100.

The circuit runs from a single 6V battery and the output 

zero is offset by about 1V by referring everything to an 

internal common line at a voltage set by a pair of 

forward-biased silicon diodes. This is convenient for 

interfaces with a 0-5V input.

Components are not critical but the two 2.2uF capacitors 

must be able to stand some reverse bias so they should be 

non-polarized. To get the expected result, the potentiometer 

is adjusted, so that the output is about 2V peak. The trace 

should look like this:

Heart rate trace

Pulse Plethysmograph results during deep breathing

Actually this experiment's result is achieved by using the 

PicoLog software. From this software the expectation 

waveform will display clearly as required. 

So, I'm just trying the circuit by using the oscilloscope 

in lab. The sensor I changed to LDR and Red LED.

The result I obtained is shown as the pictures below:

When the sensor not touched

When the sensor is touched

The first waveform is produced is quite same with

the expected result just had the noise.

The problem I had is, when I'm connected to 

ground, the waveform is not displayed at above.

It was displayed like too much of noise and 

no pattern of waveform can be seen. When I'm 

not connected the ground the result is displayed 

at above.

The potentiometer I'm already adjusted but the 

waveform is still not give any pattern if I'm 

connected to the ground. If I'm disconnected the 

ground the waveform is displayed. 

The sensor I'm already change to the 

IR transmitter and receiver. But the result still the 

same.

The circuit was constructed

Week 7 - Research on the Plethysmograph

As salam..

As the previous post, I'm still on the research the
circuit. For this week, I'm proceed to do a research
for the next circuit that might be suitable for the
measurement of heart rate and pulse oximeter.

I'm also asked the senior that had an experienced

in a project of pulse oximeter and heart rate. Mostly 

few senior that I met, told me that they are used 

plethysmograph. That was my first time heard that kind

of name. ISo that, I'm doing my research on that 

plethymograph circuit. What I found is :

Plethysmograph is an instrument for measuring changes in

volume within an organ or whole body (usually resulting 

in the amount of blood or air it contains). 

A photoplethysmograph (PPG) is a plethysmograph that 

uses optical techniques. A pulse oximeter measures oxygen 

saturation level (SpO2) and is also a PPG.

It can measure the change in the volume of arterial blood

with each pulse beat. This change in blood volume can be 

detected in peripheral part of the body such as the fingertip

or ear lobe using a technique called photoplethysmography.

The pulse oximeter that detects the signal is called a 

plethysmograph (or 'Pleth' for short).

The blood flow is normally shown as a waveform using a 

graph. It can provide useful information regarding the heart 

condition. Below is the different waveform with the status 

of heart beat.

Heart Rhythm

Pleth is useful to detect irregular heart rhythm. The regular

beating or contraction of the heart moves the blood throughout

the body. The heart beating pattern is clearly displayed by 

watching the pleth waveform. This is important to observe the 

pleth waveform because from that the doctor can know 

the condition of the patient's heart.

Signal Strength

Weak signal is indicated by the amplitude of the waveform. 

If the signal is too low, it would affect the accuracy and 

functioning of the pulse oximeter. If your oximeter is not 

giving the correct result, check if the signal strength is too 

low.

There are several causes for the weak signal:

• Low blood perfusion
• Dirty sensor or LED lights
• Improper positioning of the oximeter

All the info I found is help to understand what is actually 

Plethysmograph.. Next post will be about the circuit of

plethysmograph.

(Week5 - Week 6) Research on circuit

As salam..

Since Week4 is the Eid holiday..
I'm continued my research and testing the circuit in
Week5 and Week 6.. :)

As the previous post I had mentioned that my pulse
sensor is already failed in functioning.
This post will focus on the a few circuits that I had
done that is compatible to measure the heart rate
and pulse oximeter. So, I had make some research
about some circuits. Below is the first circuit that I
had tried that used Arduino programme.

Schematic circuit of Pulsometer

The Op-amp that used in this circuit is LM324.
IR led and LDR are used in this circuit.

LM324 is a 14 pin IC consisting of four independent 

operational amplifier (op-amps) compensated in a 

single package. Op-amps are high gain electronic 

voltage amplifier with differential input and a single-ended 

output. The output voltage is many times higher than the 

voltage difference between input terminals of an op-amp.

Theses op-amps are operated by a single power supply 

LM324 and need for a dual supply is eliminated. They 

can be used as amplifiers, comparators, oscillators, 

rectifiers etc. The conventional op-amp applications can 

be more easily implemented with LM324. Here are the
LM324 pin diagram and description. 

LM324

Pin diagram

Pin description

Below is the video that shows successful of the circuit.

As shown, there is working prototype that graphs pulses 

on computer that based on data from serial port. Work 

is going on signal processing to output pulse data, not only 

digital pulsations.

The goal is to build a separate digital/analog sensor for

arduino with possibility  to log data for future reference.

Below is the video of the result that I obtained from 

the schematic circuit that shown in early of this post.

As you can see the graph not stable like the one that
success. When I touched the LDR sensor, it gave the
shape of waveform. When I am not touched it, it became
a flat graph. I had tried to adjust the variable resistor,
but the result still the same.

When I'm looking on the serial monitor, the result in
analog supposedly about 400++ to less than 600.
But the number displayed is fixed to 1000
and that is when I'm not connected to ground.
When I'm connected to ground the reading is going
down to 0.

I'm also tried by change the sensor the LDR to the
IR transmitter and receiver. There is no result is
obtained.

Then, I'm proceed to try other circuit. That one will be
posted for the next post because I'm still in research
for the compatible with measuring heart rate and
pulse oximeter.

(Week 1 - Week 3/FYP II) Pulse Sensor

As salam..
After a few months I'm getting back to update my progress
of my final project.For the semester break, I had done the
research of circuits that is match for my project. The circuits
are included for measuring :
(a) Body temperature
(b) Heart Rate
(c) SpO2

After discussed with Sir Zul (supervisor), the body temperature
is not important in this project. So, I've just focus for the
other two parameters, heart rate and SpO2. For the heart rate,
I had make an order for the 5V pulse sensor.
Badly, the sensor was not in stock in Malaysia.
So, I need to make an order from  www.pulsesensor.com

The time to be arrived is about two weeks.
When I received the sensor, straightly I'm tried the sensor by
running the program of arduino and processing.
For the early few times in testing, the waveform that should be
produce in processing was not displayed any results.
The heart beat was stick with 0 bpm.
But the sensor still gave a result by blinking the red led when
we touch the sensor without run the program. Which means the
sensor is sensed and well-functioned.

Then, I met Sir Zul by showing him the sensor and informed him
what was the matter that I faced. So, what he was done, he just
edit the serial port by looking on the COM No.
Which is means, the serial port had displayed 3 ports :
COM3, COM6 and COM11.

The COM was running in arduino is COM11.
In processing the COM11[2] should be written in the program.
If let say the serial port is COM6,
it should be written COM6[1].
So, the problem is solved by edit the serial port.
The result is displayed as required.
Unfortunately, the picture of the result was not taken.

I was said that because after it was success, when I want to
try it back for the next few days, the sensor was back by not
gave any result.When I connected to the A0, the LED not blink.
When I touched the sensor the LED still not blink.
It means that no sense detected.
When I'm running the program for arduino and processing,
the result not showed as required.
I'm trying so many times, and the result still the same.
So, what can I do is construct the circuit that suitable for measuring the
heart rate.

The sensor that will be used is LDR and Red LED.
The IC will be used LM358 or LM741.
The explanation about the IC will be update in the next post.
Below is shown how is the pulse sensor was looked.

The packaging of  5V Pulse Sensor

The pulse is applied to the finger and the Red LED is blinked at that time

The flow of the project

As shown in the previous post, that is how actually

remote patient monitoring system is working out.

After had the discussion with my supervisor,

I've decided to change the flow of the project.

Actually, the project is takes time to complete.

It might take about 2 years to finish the project.

The flow of the project is also quite complicated.

That is because there are a lot of parts that relate

with the telecommunication system.

So, the application of PDA then link to the web 

server and the data is directly accepted by the clinician
through their own gadget (laptop) are changed.

It will be changed with this flow that shown below :

The system of Remote Patient Monitoring System by using the iOBridge

Block Diagram of Remote Patient Monitoring System

From the block diagram is shown at above, the sensor
is consists of the measurement blood pressure, heart
rate and the oxygenated in blood (SpO2). Then, the
measuring data will convert to digital through the ADC.
This parts are acts as the input. The data will transmit to
the clinician's gadget (hand phone, laptop and PDA) that
acts as the output, by passing through the Internet
Enabled Microcontroller also known as the processor.
The microcontroller that chosen from the reseacrh is
iOBridge-204.

Next post will explain how the progress of the project. :)

What is the Remote Patient Monitoring ??

~  Remote Patient Monitoring is a system that will monitor

   patients at their bed or home by clinician through the    

   remote location at the hospital.

~  Architecture of the system : 

Figure 1 

   

  (a) In Figure 1, the basic of model in generally : 

      i - Medical Sensor Module will be attached to 

          the patient to record the patient's data.

     ii - The data will be forward to the PDA through

          a wired channel (USB or serial port).        

              

* The PDA will contain an application for local monitoring

  of patient's data that would display the current readings.

     

    iii - The PDA will connect to a remote server and transfer 

          the data to it.

    iv - The remote server will process the data, the Clinical

          Decision Support System to perform analysis data. 

     v - The Electronic Medical Record service to record the

         readings in the patient's history and provide feedback

         to the PDA screen notifying the decision given by the

         Clinician Decision Support System.

~  The web server also handle requests from the clinician's

   terminal and provide reports about the patient's situation.

~  An electronic medical record system will be used to store 

   the incoming data to the patient's record. 

~  The clinical decision support system will provide automated 

   analysis of data and assist the clinician in decision making 

   process.