User:N ngea/ENES100/Project 1

Project Preference
- Mobile Hallway Navigation - Bio-engineering Project - Project MakerBot PLA Material Characterization

Problem Statement
As of today, here are the two goals:


 * Detect accurately and warn when body vitals are critical.
 * What would be a good idea for a bio-engineering project?

Project Plan
In order to achieve the goals mentioned above, we have devised the following tentative plan:

This is the most critical part so I think spending enough time to come up with solid data and parameters will make the "making" stages easier and worthwhile.

Week 1 Narrative
This week, we discussed what this bio-engineering project might be. The idea that stood out is to work on a device (precisely a cloth, iron man "heart" style) for seniors that will take the body vitals and lighten and/or emit a sound when those vitals are not good. The cloth is just an idea. The survey might modify the way the device will look like.

We are also exploring other ideas, for this project will be a project conception. With that in mind, we decide to do some surveys and benchmarking to find if such a product will have a market.

We looked at what the competition offers. It helped us narrowed our options (what we should be aiming at), and identify more targets (children and anybody that needs to be monitored at all times). We also realized that our survey should be directed at medical professionals and public safety officers as well. With that in mind, we designed a to do our surveys. Each member was given a specific target to work on. I had the medical and public safety personnel, any other target that was not an athlete or a senior. The results will be discussed during our next meeting

We are still waiting for a reply to the email we sent to the responsible of the emergency and paramedics program at HCC to help us with metrics and the best ways to get accurate vitals' readings.

Week 2 Narrative
The project has been approved: a cloth that will take your body vitals. We were finally able to interview the Director of Paramedic and EMS at Howard Community College. From the information that we gather, we decided that the device should be able to measure:
 * The heart and respiratory rates using the 12-lead ECG and the intercostal muscles,
 * The blood pressure,
 * May be the body temperature.

Our survey pointed the need for accuracy so we were to find and define accuracy for the body vitals we are interested in. We are hoping this will help to define once and for all the functions of the cloth. This week, my work was to research blood pressure. The following table from the NIH Medline Plus magazine should tell us what ranges we are interested in:

Here are the requirements for an automated device taking blood pressure from the Association for the Advancement of Medical Instrumentation (AAMI) from here:

A sphygmomanometer is a device that measures your blood pressure (systolic and diastolic). There are manual and digital (Also known as oscillometric blood pressure)ones and both use a cuff. The digital sphygmomanometer uses a piezoelectric sensor that measures pressure and converts it to electrical charge. The blood pressure is not really measured but calculated with algorithms. Also, you cannot just take blood pressure anytime or the reading will not be reflective of your current health. Finally, though some progress have been made to improve accuracy on digital devices, they are still not reliable. The auscultation method remains the most reliable.

Taking the blood pressure was considered as a feature on the device but we may end up not having it at all.

Here are the following functions for our device: https://en.wikiversity.org/wiki/User:Medelen8/ENES100/Bioengineering_Project_Conception#System_goals_and_requirements
 * Take heart rate;
 * Take respiratory rate;
 * Take temperature (to be discussed)

Week 3 Narrative
In order to define the final functions of our device, we met with Angel Burba, MS, NREMTP, NCEE Associate Professor, Director of Paramedic and EMS at Howard Community College. We gather that temperature is not needed but she asked about a pulse oximeter. As we found this shield for biometric applications, we decided to add this feature for the vest. It will provide an additional layer of diagnosis for both cardiac and ventilation systems. Our assignment this week was to work on oxygen saturation by pulse oximetry, accuracy, algorithm and devices.

According to Johns Hopkins Medicine Health Library, pulse oximetry is a non-invasive procedure to measure the oxygen level in the blood. It uses "the light absorptive characteristics of hemoglobin and the pulsating nature of blood flow in the arteries to aid in determining the oxygenation status in the body". A probe housing a light source, a light detector and microprocessor is used: One side of the probe ( in our case a finger probe) has the light source, infrared for oxygen-rich hemoglobin and red for the hemoglobin without. The processor, on the other side, will calculate the differences (called R, "ed".)and convert the results to digital information.

This technology review tells us how a pulse oximeter works: "Pulse oximeter sensors contain two light emitting diodes (LEDs) used for shining red and infrared (IR) light through blood-perfused tissue. On a heartbeat-by-heartbeat basis, a small amount of arterial blood is pumped into the tissue, which then slowly drains back through the venous system. The amount of the sensor’s emitted light that passes through blood-perfused tissue, such as a finger, varies with this cycling blood volume: The more light absorbing blood present, the less light that travels through the tissue bed to strike the sensor’s photodetector. Pulsatile signals allow pulse oximeters to evaluate the signal attenuation caused by arterial blood flow, since light absorption from other tissues is generally unchanging."

The pulse oximeter uses the Beer-Lambert-Bouger Law to evaluate that ratio between the wavelengths and (because the law is too simplistic) calibration of the device using look-up tables. The following formulas (found on this document) are used:
 * $$ T = {I\over I_{0}} = 10^{-\alpha\, \ell} = 10^{-\varepsilon\ell c} $$


 * T: Transmission
 * α: Absorption coefficient of the substance
 * ℓ: The distance the light travels through the material
 * ε: Molar absorptivity (extinction coefficient) of the absorber
 * c: Molar concentration of the absorbing species

This study provides also additional information on how to determine the respiratory rate from the pulse oximeter signals (PPG). The following http://link.springer.com/article/10.1007%2FBF00560145?LI=true#page-1 might be useful as well

From our research, we gather that the pulse oximeter must be accurate above 94% to provide critical information.

Finger probes are easily found and can be used on Arduino Boards. However, the system (pulse oximeter system) as a whole to provide great accuracy as mentioned in this study:

More information on the architecture, design and solutions for the pulse oximeter can be found here and here.

See the Conception report for respiratory and pulse rate along with more on the architecture of the pulse oximeter.

Week 4 Narrative
For this last week, we were to work on our presentation at the Engineering Club this past Thursday. We were to also finish the CDIO report taking into account the teacher's remarks after the weekly presentation.

In that regard, we met with the other team members and decided on what, how will be the presentation and tasks were assigned

During the meeting was also discussed which parts of the cdio report needed to be completed. We were to focus on what must be passed to the next team (system and requirements, function and concepts) and ensure they were properly defined. Therefore, I was to choose the sensor I needed and make sure it could be incorporated in the architecture of the device, that it was affordable, about 0.1 lb and compatible with Arduino and/or the shield, and that it could be used with the many projects I found so far.

http://pulsesensor.myshopify.com/pages/pulse-sensor-amped-arduino-v1dot1

http://www.eevblog.com/forum/microcontrollers/pulse-oximeter-using-arduino-uno-raspberry-pi-and-xprotolab/

Our research pointed us to Nellcor finger sensors. They have affordable finger sensor and seem to be compatible with different architecture. They can also be used with test to check measurements.You can also the sensor you need here.

The finger probe cable should have at least 7 pins, 9-pin is even faster and would be ideal.

We also focused on what would be the next steps to take this project further.

https://en.wikiversity.org/wiki/User:Medelen8/ENES100/Bioengineering_Project_Conception#Development_Project_Management