ATECHTOP Final Video Spring 2015

By Shiela Caridad: ATECHTOP Mission Systems and Test Engineer

Approved and posted by Robyn Goss: ATECHTOP Project Manager

This video is meant to showcase how we utilized the engineering method to produce our wireless body area network, ATECHTOP.

 

Engineering Method

  1. Identify the Problem
  2. Define the problem (requirements)
  3. Form creative design solutions
  4. Overcome obstacles
  5. Make hardware/software models/ perform experiments
  6. Organize and analyze data
  7. Check that experiments meet design requirements
  8. Select a preferred design
  9. Communicate results
  • Implement the design

 

The main objective of our project was to produce a wireless body area network that would monitor the vital signs (blood oxygen content, heart activity, body orientation, and body temperature) of children with health complications and subsequently, allow them more freedom when playing.

 

Atechtop Spring 2015 Team:

Robyn Goss – Project Manager

Shiela Caridad – Missions, Systems, and Test Engineer

Li Chen Yeh – Manufacturing Engineer

Kenia Garcia – Electronics Engineer

 

Atechtop Spring 2015 would like to thank:

CSULB, College of Engineering

CSULB, Department of Electrical Engineering

Arxterra

ATECHTOP Final Documentation

Introduction to ATECHTOP’s Purpose and Objective:

Play is essential to youth development, as it contributes to the cognitive, physical, social, and emotional well-being of a child, particularly between the ages four to five [1,9].  There are a number of debilitating diseases which require intensive medical monitoring and special supervision, limiting a child’s ability to play.

ATECHTOP intends to design a wearable body area network capable of monitoring the following physiological parameters:

  • Blood oxygen content
  • Heart activity
  • Body orientation
  • Temperature

The wireless design will allow children greater freedom to socialize while adults are able to monitor their child’s physiological signals from a distance.

Greater details on the vision of the ATECHTOP project may be explored here.

 

Introduction to the ATECHTOP Team:

The engineers working to make ATECHTOP a reality include:

Robyn Goss, ATECHTOP Project Manager

Shiela Caridad, ATECHTOP Mission Systems and Test Engineer

Kenia Garcia, ATECHTOP Electronics Engineer

Li Chen Yeh, ATECHTOP Manufacturing Engineer

The following is a description of tasks headed by each group member:

Robyn Goss Project Documentation
Facilitation and Planning of Group Meetings
Scheduling and Planning
Project Requirements Design
Management of Budget
Initial Solidworks Design
Kenia Garcia PCB Design
Power Budget Descriptions
Mass Budget Descriptions
Investigation of Battery Selection
Soldering of Materials
Li Chen Yeh Software Design and Implementation
Arxterra Implementation
Pulse Oximeter Test and Design
Sensors Testing
Hardware Implementation
Shiela Caridad Solidworks Design
Description of Verification Test Plans
System Block Diagram Design
Interface Definitions Description
Design of Initial Tests/Experimentations
Pulse Sensor Acquisition

ATECHTOP’s progress could not be accomplished without the determination and hard work of each group member involved.

 

ATECHTOP Project Requirements:

The design phase of a project begins at the definition of requirements. Requirements are defining structures which frame project design and remind engineers of the ultimate objective, and the methods of achieving the design. If properly defined, project requirements will prevent an engineer from wasting time and arriving at an incorrect solution.

ATECHTOP requirements follow two levels: Program and Project requirements (Also called “Level 1 Requirements”) and System and Subsystem requirements (Also called “Level 2 Requirements”).

The following link will take readers to ATECHTOP Level 1 and 2 requirements if interested in the details of the project.

 

ATECHTOP Final Design:

The final ATECHTOP design was selected for its marketability and comfort during physical activity. The final design utilizes a chest harness with sensors attached to the straps of the harness.

The following image reveals the expected look of the chest harness with exception of the sensors and straps. The frontside of the harness will carry the phone, and the backside will carry the sensors, PCB, Lilypad, and battery of the sensor suite.

sheila1

 

20150515_140939

The above image demonstrates a five year old boy wearing the ATECHTOP sensor suite. There are four pockets along the back straps: two along the spine and three (or two additionally) along the midline. The three pockets along the midline contain respectively from left to right: the accelerometer and bluetooth module, the Arduino Lilypad, and the battery power supply. The two pockets along the spine contain respectively from top to bottom: the custom PCB design and the Arduino Lilypad.

Further detail regarding the design evolution of the ATECHTOP sensor suite can be found in the following blog post.

 

 

System Design:

The following is a representation of the system project block diagram. It should be noted that the block diagram is a modification loosely based on the previous semester’s project block diagram design which may be accessed here.

6

The system block diagram is color-coded as follows:

Orange Sensor suite
Blue Software
Green Hardware
Red Power
White Users

The system signals are color coded as follows:

Light Blue ADC Signal
Blue I2C Signal
Dashed Blue Bluetooth Signal
Dashed Gray WiFi Signal
Red Power

The sensor suite sends analog signals to the battery-powered Arduino which digitizes each signal.  The digitized signals are then sent to the Bluetooth module/antenna which transmits its signal to the Android phone.  The Android phone is equipped with the Arxterra software which is paired with the Arxterra website. The Arxterra website is accessible via pc or phone.

 

 

Project Interface Definitions:

The following image describes the interface definitions necessary to implement ATECHTOP sensors with the Arduino Lilypad microprocessor:

7

The reason for selection of Arduino Lilypad for use is discussed here.

An introduction to the ATECHTOP sensors and the reasons for their selection is discussed here.

ATMega328V LilyPad ECG O2 Meter Accelerometer Temp Sensor Bluetooth Module
VCC VCC
GND GND
PC5 A5
PC4 A4
PC3 A3
PC0 A0
PD7 7
PD5 5
PD2 2
PD1 TX
PD0 RX

Appropriate pin outs were defined via each sensors given specification sheet.

 

 

Experimentation of Pulse Oximeter Sensor:

The 2015 ATECHTOP group decided to implement a pulse oximeter circuit on their own without the use of a pre-designed circuit.

Circuit Design

Design inspiration can be found in the following documents : Document 1:Pulse Oximeter Design Inspiration and Document 2: Beer’s Law Tutorial.

Two prototype models were constructed and tested, the details of which can be found in the initial testing blog and in the rapid prototype testing blog.

PCB Implementation

Software input inferred that the sensor was working as expected, and PCB implementation marked the final stage of pulse oximeter circuit input.

Details regarding PCB design are described in detail in the following link.

Ear Clip Design

shiela3

The pulse oximeter circuit then needed a way of connecting to the earlobe in order to obtain physiological readings. The group designed a 3D model for an ear sensor clip using Solidworks software which can be seen above. The final design is compact, making it less conspicuous which may save a child embarrassment or discomfort when playing.

close-up

The image above shows our five year old test model Juan Colarte wearing the pulse oximeter on the lower earlobe and the pulse ECG sensor on the upper ear.

Code Implementation

The pulse oximeter sensor is a home made sensor using the transmission method. Sample code is provided in the following blog. Parts of the code were modified in order to work on arxrobot_firmware.

The code was implemented onto Arxterra so that a blood oxygen percentage would update each minute. A description of the process is listed in the following blog post.

For more details, please refer to the following telemetry lecture and the github example.

Verification Testing

The pulse oximeter’s testing was completed May 8th, the results of which are described in the following blog post.

 

 

Experimentation of Temperature Sensor:

The 2015 ATECHTOP group decided to implement the temperature sensor using the LM74 transistor.

Circuit Design

Implementation of the sensor with the Arduino Lilypad board is modeled by the following documentation. Figure 3.12 in the documentation was referenced by the ATECHTOP group to connect the sensor.

Testing of the originally selected temperature sensor is documented in the following blog. The output is expressed digitally in Celsius on the Arduino serial monitor window when using the code provided by the same source mentioned above. The final temperature sensor was changed to the LM74, as the original temperature sensor coding was not compatible with the selected pulse sensor. Initially temperatures were taken once per second while ATECHTOP later modified temperature to be sampled only once per minute.

PCB Implementation

Software output inferred that the sensor was working as expected, and PCB implementation marked the final stage of pulse oximeter circuit input.

Details regarding PCB design are described in detail in the following link.

Code Implementation

Reference code used to implement the temperature sensor readings is provided in the following link. Parts of the code were modified in order to work on arxrobot_firmware. The code was implemented onto Arxterra so that an integer temperature value would update each minute. For more information regarding Arxterra software implementation, please refer to the following blog post.

For more details, please refer to the following telemetry lecture and the github example.

Verification Testing

The pulse oximeter’s testing was completed May 8th, the results of which are described in the following blog post.

 

 

Experimentation of Electrocardiogram Sensor:

The 2015 ATECHTOP group decided to implement the Pulse Sensor Amped to monitor physiological heart activity.

Circuit Design

Design inspiration can be found in the following document.

Implementation of the heart sensor Amped required simple connections to the Arduino Mainboard as can be seen in the schematics and images provided in the documentation.

PCB Implementation

Software input inferred that the sensor was working as expected, and PCB implementation marked the final stage of pulse oximeter circuit input.

Details regarding PCB design are described in detail in the following link.

Ear Clip Design

The Pulse Sensor Amped provided the material to implement an ear clip to detect physiological heart activity. The ear clip was attached to the ECG sensor using a hot glue gun. The clip can be seen below as it was attached to a young child to monitor heart rate data.

IMG_0072C

The design is more stable during manufacture, and is also less fragile. The compactness of the clip makes it less conspicuous which may save a child embarrassment or discomfort when playing.

Code Implementation

The pulse sensor was purchased from Sparkfun. Sample code is provided by Sparkfun and may be referenced in the following link. Parts of the code were modified in order to work on arxrobot_firmware. The code was implemented onto Arxterra so that an output of beats per minute would update four times each minute. For more information regarding Arxterra implementation, please refer to the following blog post.

For more details, please refer to the following telemetry lecture and the github example.

Verification Testing

The pulse oximeter’s testing was completed May 8th, the results of which are described in the following blog post.

 

 

Experimentation of Accelerometer and Body Orientation Sensor:

The 2015 ATECHTOP group decided to implement the MPU6050 sensor to monitor a child’s body orientation along the three-dimensional axes: yaw, pitch, and roll. Understanding of body orientation is important  specifically for detection of sudden falls or prolonged inactivity. Sudden falls can be serious enough to require immediate medical assistance; Inactivity can also be a sign of conscious loss which necessitates parental notification. An introduction to the MPU6050 sensor can be explored in the following blog post.

Circuit Design

Manipulation of the sensor to work with the Arduino processor was not a difficult task which is one of the reason’s for this particular accelerometer’s selection. Description of connections for testing may be found on the following blog post.

Accelerometer Output

Successful testing of the accelerometer is fully documented in the following blog post.

Output using an Arduino sketch documented in the aforementioned blog post reads the data from the sensor’s digital motion processor, and outputs the Euler angles yaw, pitch, and roll on the Arduino serial monitor. These values can be transformed graphically to represent motion in three-dimensional space. Current Arxterra limitations do not allow graphical display of the accelerometer motion using the MPU6050 sensor, however, does display motion using the accelerometer in the mobile device.

PCB Implementation

Software input inferred that the sensor was working as expected, and PCB implementation marked the final stage of pulse oximeter circuit input.

Details regarding PCB design are described in detail in the following link.

Code Implementation

The code was intended for continual update of sensor motion in 3D space. Because of lack of time for Arxterra to develop these capabilities, Arxterra instead reads body orientation through the mobile device. A description of the process which in the future is hoped to be implemented is listed in the following blog post. This includes use of the accelerometer sensor rather than the phone accelerometer.

It is hoped that in the future, Arxterra will be capable of graphical display to represent motion and body position using the modified and tested ATECHTOP sketch.

Verification Testing

The pulse oximeter’s testing was completed May 8th, the results of which are described in the following blog post.

 

 

Verification Tests Plans:

Verification test plans were initially documented within project requirement documentation. Sheila Caridad, Mission and Systems Engineer designed detailed verification test plan documents to better track system requirements and project accomplishments.

Results of verification include: budget, range of motion, bluetooth, clothing material, and Arxterra. The summation of these requirement tests encompasses all needs expressed by project requirements, and are documented in greater detail in the following blogs:

Budget Verification Test

Range of Motion Verification Test

Bluetooth Verification Test

Material Verification Test

Arxterra Verification Test

 

 

Project Status Reports:

Power report (includes battery selection), mass report, and cost report can be found in the appropriate blog posts.

Project Completion Status:

Revised ATeChToP Schedule V2

The above image is a detailed schedule providing date-based outlines for each project task necessary for ATECHTOP to become a reality before the end of the CSULB Spring semester. The schedule is a modified version from the schedule outlined by last semester’s ATECHTOP group [5]. Specific tasks were omitted, deadlines were altered slightly, and the schedule as a whole was developed to be more specific. The schedule kept the final documentation deadline of April 30th in order to force the group to work more efficiently and to also allow room for last-minute alterations or possible disasters and setbacks. Final documentation was not finished by April 30th: All testing and implementation of the sensors were finished by May 8th which is two weeks behind the projected deadline, and one week before final implementation was necessary.

The group still feels as though their usage of time was successful, as the deadlines provided were intentionally set earlier than entirely necessary. This left room for error in the design process, as well as possible complications outside of class. Because of this, the final weeks of the semester resulted in stress-free testing, and no major modifications.

BurnDown pic

Currently, the total project is divided into eighteen tasks. This breaks down into each task making up roughly 5.55% of the finished project implementation. By the final day of the Spring semester, ATECHTOP completed 100% of allotted tasks.

 

Concluding Thoughts:

It is hoped that future ATECHTOP groups will be able to implement the requirements that the Spring 2015 ATECHTOP could not regarding parental controls and accessibility of the Arxterra application. In the future, it would be beneficial for parents to be able to customize the Arxterra alert system, to archive physiological data, and to view graphical displays of both the heart activity and the body orientation.

In order to benefit a greater number of children, future ATECHTOP groups might also begin looking into additional sensors for the body network.

 

A Special Thanks to:

California State University Long Beach College of Engineering

California State University Long Beach Department of Electrical Engineering

Professor Gary Hill

Jeff Gomes for Arxterra assistance

Larry Harmon for Arxterra assistance

Tate McGeary for Arduino software assistance

Sarah Rice for Arduino software assistance

Andrew Yem for Bluetooth assistance

Austin and Malia Vlasich for modelling the sensor

 

References: 

[1] Ginsburg, Kenneth R. “The importance of play in promoting healthy child development and maintaining strong parent-child bonds.” Pediatrics 119.1 (2007): 182-191.

[2] Lee, Jin-Shyan, Yu-Wei Su, and Chung-Chou Shen. “A comparative study of wireless protocols: Bluetooth, UWB, ZigBee, and Wi-Fi.” Industrial Electronics Society, 2007. IECON 2007. 33rd Annual Conference of the IEEE. IEEE, 2007.

[3] Lee, Jin-Shyan, Yu-Wei Su, and Chung-Chou Shen. “A comparative study of wireless protocols: Bluetooth, UWB, ZigBee, and Wi-Fi.” Industrial Electronics Society, 2007. IECON 2007. 33rd Annual Conference of the IEEE. IEEE, 2007.

[4] Dowshen, Steven MD. (2013)  “Backpack Safety”  Kidshealth.Org  Retrieved from http//kidshealth.org/parent/positive/learning/backpack.html

[5] Cabingatan, Monica, Edward Diego, Hector Medina, and Gianfranco Parreno. “Bioengineering Project Final Documentation.” Web log post. Arxterra. N.p., 15 Dec. 2014. Web. Jan.-Feb. 2015. <https://www.arxterra.com/bioengineering-final-documentation-atechtop/>.

[6] IEEE Computer Society. “IEEE Standard for Local and Metropolitan Area Networks – Part 15.6: Wireless Body Area Networks.” IEEE. LAN/MAN Standards Committee, 06 Feb. 2012. Web. Jan.-Feb. 2015.

[7] Barthe, Patte. “Time Out: Is Recess in Danger?” Center for Public Education. Center for Public Education, 6 Aug. 2008. Web. 19 Feb. 2015.

[8] United States of America. National Center for Health Statistics. 2 to 20 Years: Weight-for-Age Percentiles. Centers for Disease and Control Prevention, 30 May 2000. Web. 22 Feb. 2015.

[9] Gurian, Anita, PhD. “The Preschool Years: (ages Four and Five) Expectations and Challenges.” The Child Study Center. American Academy of Child and Adolescent Psychiatrists, 2004. Web. 22 Feb. 2015.

[10] Standardizing Information and Communication Systems. Safety of Electronic Equipment. ECMA International. 2002. PDF file. Figure 3.1

[11] 704, and Invensense. “MPU-6000 and MPU-6050 Product Specification Revision 3.2.” Release Date: 11/16/2011 MPU-6000 and MPU-6050 Product Specification Revision 3.2 (n.d.): n. pag. 16 Nov. 2011.Web.

[13] SparkFun. “Pulse Sensor.” – SEN-11574. N.p., n.d. Web. 13 Mar. 2015.

[14] Drupal. “Standard Body Measurements/Sizing.” Standard Body Measurements/Sizing. N.p., n.d. Web. 13 Mar. 2015.

[15] “Size Chart.” Vineyard Vines. N.p., n.d. Web.

[16] “Sportswear Fabric | Sports Clothing | Custom Jerseys | Danbury, CT.” J-Teck USA. N.p., n.d. Web. 13 Mar. 2015.

[17] 436 Kato Terrace Fremont, Ca, 94539, Tenergy Corporation, and Tel: 510-687-0388 Fax: 510-687-0328. “TENERGY 9V 250mAh NiMHBattery.”TENERGY 9V 250mAh NiMH Battery (n.d.): n. pag. Web.

[18] “Turnigy 2200mAh 3S 25C Lipo Pack.” HobbyKing Store. N.p., n.d.Web. 13 Mar. 2015.

[19] Silicon Labs, “Proximity/Ambient Light Sensor IC with I2C Interface,” Si1141/42/43 datasheet. Oct. 2014.

[20] Dallas Semiconductor, “DS18B20 Programmable Resolution 1-Wire Digital Thermometer,” DS18B20 datasheet.

[21] Fritzing, Ver. 0.9.1b. 2014.  Desktop Application.  Viewed on Feb 25, 2015. <https://www.fritzing.org>

[22] Arduino-Uno-Rev3-Schematic PDF.  Viewed on Feb 25, 2015.  <http://arduino.cc/en/Main/arduinoBoardUno>

[23]http://ncalculators.com/electrical/battery-life-calculator.htm

 

 

 

Power Budget and Battery Selection

By Robyn Goss and Kenia Garcia: ATECHTOP Project Manager and ATECHTOP Electronics Engineer

Tracking the power consumption of the body network system is imperative in keeping within reasonable project limitations. Battery usage and length of operation time are highly dependent on the consumption of power by the body network. Level 2 requirement 8 states that battery must be capable of powering the device for at least 30.2 minutes without requiring recharge (see project requirements).

The following table lists the average current and voltage required for each component. Adding the currents together provide a rough estimate of the total projected current consumption needed for the system. Current consumption is related to power consumption by the relationship: Power = Current * Voltage.

 

Circuit Component Theoretical Max Current (mA) Operating Current (mA) Theoretical Max Voltage (Volts) Operating Voltage (Volts) [as measured using DMM] Theoretical Max Power (Watts)
Pulse Oximeter 360 5.6 3.6 2.9 1.296
Temperature Sensor 1.5 1 4.95 2.92 .00825
Pulse Sensor

[13]

4 4 5 3.3 0.02
Accelerometer

[11]

3.9 3.9 6 3.46 .0234
Bluetooth [12] 30 8 3.3 3.3 .099
Lilypad Arduino [21][23] .3 .3 20 4.99 1.2

 

Battery Selection

The total current consumption dictates the battery selection to those batteries which are capable of supplying the system needs. The estimated current consumption is 22.8mA. In order to fulfill the level 1 requirement of system duration, our battery must have a minimum capacity of 16.39 mAh (see equation below). With this information, we were able to search for appropriate batteries. The table below lists multiple batteries that fulfill our set requirements, including battery capacity.

The nature of ATECHTOP yields the additional requirement of safety. Because the body network is intended to be worn by young children, selection of the battery must reflect safety concerns with regards to the reaction of battery if accidentally damaged or punctured. LiFePO4 is a battery type with the ability to provide the necessary current loads while remaining safe in the face of damage. The following table lists potential choices for the battery which will be implemented into the body network.

 

Voltage Capacity Weight Dimensions Max Temp (Celsius) Cost
K2 Cell LiFEPO4 3.2V 1250maH 36.8g 65x37x23
mm
<60 $12.50
LiFePO4
18650
3.2V 3000maH 102g 68x37x21
mm
<60 $19.95
Turnigy Nano-tech 11.1V 3300maH 263g 146x43x20
mm
<60 $26.95
Tenergy NiMH 9V 250maH 50g 45x30x18 mm <50 $21.99

 

Range of Motion Verification Test

Verification Testing: Range of Motion

Objective

The objective of this test is to verify that the child/user of ATECHTOP will be able to safely and comfortably retain a full range of motion.

 

Test Equipment:

Scale

Goniometer

 

Procedure

  1. A group member will weigh each component separately and then the ATECHTOP product as a whole. The group member will verify that the total mass does not conflict with the mission requirement.  Note all findings on the appropriate data sheet.
  2. A group member will wear the ATECHTOP product and complete a variety of movements as listed on the appropriate data sheet. Ease of movement will be evaluated by health professional standards and recorded on the appropriate data sheet.
  3. The group member testing the ATECHTOP product will note the placement of each sensor on the appropriate data sheet.

 

Results

All sensors were place appropriately.  Total weight of ATECHTOP project is within weight limit as stated within project mission requirements.  ATECHTOP wearer was able to complete all necessary movements with ease and comfort

The results of this verification test will ensure compliance with the following requirements:

Project Level 1 Requirement #5: The complete body network should not exceed 2.9 lbs.

Project Level 1 Requirement #9:  Child should be able to maintain personal full range of motion while wearing the body network.

Project Level 2 Requirement #3: Sensor location for the ECG and pulse oximeter will be placed on each earlobe.

NOTE:  Project requirements are as listed in the Project Requirements blog post.

 

Verification Data Sheet: Range of Motion

 

Name: Shiela Caridad Date: May 7, 2015

 

Left Extremity Motion Right
Comfortable Shoulder Flexion Comfortable
Comfortable Shoulder Abduction Comfortable
Comfortable Shoulder Internal/External Rotation Comfortable
Comfortable Shoulder Horizontal Abduction Comfortable
Comfortable Elbow Flexion Comfortable
Comfortable Elbow Extension Comfortable
Comfortable Neck Flexion Comfortable
Comfortable Neck Extension Comfortable
Comfortable Neck Rotation Comfortable
Comfortable Back Flexion Comfortable
Comfortable Back Extension Comfortable
Comfortable Trunk Rotation Comfortable

 

 

Mass Verification Data Sheet

 

Name: Shiela Caridad Date: May 5, 2015

 

Individual Components Mass (g)
Pulse Sensor Amped! 8
Pulse Oximeter 3
Waterproof Temperature Sensor 42
MPU-6050 2
Custom PCB 5
Arduino Lilypad 4
Chest Harness 187
LiFePo4 Battery 22

 

Completed ATECHTOP Project 280

 

 

Sensor Placement Verification Data Sheet

 

Name: Shiela Caridad Date: May 5, 2015

 

Sensor Body Placement
Pulse Sensor Amped! Earlobe
Pulse Oximeter Earlobe
Temperature Sensor Underarm
MPU-6050 Back

 

Arxterra Verification Test

Verification Data Sheet: Arxterra Applications

 

Name: Shiela Caridad

Date: May 7, 2015

Physiological Signal

Data

Comments

Heart Rate reading

71 BPM

At rest

Blood Oxygen Level reading

99%

Body Temperature reading

35 C

Procedure

Findings

Comments

Base reading of Heart Rate

71 BPM

N/A

Raised heart rate reading

140 BPM

Heart rate raised via push ups, data measured via Samsung S-Health App

Does Arxterra clearly present the difference in heart rate?

Yes, but meter does not exceed 100.

Numerically, a clear difference is seen but label of meter is incorrect.

Procedure

Findings

Comments

Does Arxterra allow alterations of “safe” settings?

N/A

Arxterra control panel does not yet have an alterable settings tab for atechtop.

Does Arxterra prompt for a password when changing the “safe” settings?

N/A

Arxterra control panel does not yet have an alterable settings tab for atechtop.

Does Arxterra send out a timely alert when “safe” settings are breached?

N/A

Arxterra control panel does not yet have an alterable settings tab for atechtop, therefore “safe” setting were notable to be set.

Code Implementation for Sensor Suite

By: Li Chen Yeh, ATECHTOP Manufacturing Engineer

Edited and approved by: Robyn Goss, ATECHTOP Project Manager

The original temperature sensor, DS18B20, is not compatible with the pulse sensor because the temperature sensor requires 625ms of Arduino processing for acquisition of body temperature. This information can be found in the following link.

The pulse sensor implements an interrupt every 2ms, as can be understood in the following link. As the result, when temperature sensor DS18B20 is taking data, it is interrupted every 2ms by the pulse sensor. Therefore, the temperature sensor of choice changed from the DS18B20 to LM 34.

Since LM 34 is a Fahrenheit Temperature Sensor, the ATECHTOP group coded a formula to change the units of Fahrenheit to Celsius. This was necessary due to the limitation of Arxterra to output a number for temperature data which is above 100.

 

Temperature Sensor and Oxygen Sensor:

Before implementing the Arduino code to arxrobot_firmware, the following lines must be implemented in the top of the code:

#define TRUE  1

#define FALSE 1

#define debug      TRUE

#define aTechTop   TRUE

Next the “delay” function must be exchanged with the “millis” function, as the delay function will stop the entire arxrobot_firmware. Because the body temperature and the blood oxygen level should not fluctuate dramatically within one minute, it was decided that temperature data and oxygen saturation data would transmit every minute, which can be implemented using “millis” function as the following line:

unsigned long nextTempReading = millis() + 60000;

The above line is setting a variable called nextOxygenReading, which is the current time plus 1 minute.

Then, a statement must be set up as the following:

if(millis() > nextOxygenReading){

nextOxygenReading = millis() + 60000;

//Original code found here.

 

#if debug

Serial.println(“oxygen = ”);

Serial.print(oxg);

Serial.println(“temperature = ”);

Serial.print(tempe);

Serial.println();

#endif

}

The code above checks whether 1 minute has passed or not. If one minute has passed, the temperature and the oxygen level will be printed on the serial monitor window.

Then, casting must be done for both sensors since both “oxg” and “tempe” are in float data type, which means they have decimal, we need to change they into integer as following:

float temperatureC = ((((voltage) * 100)) – 32) * 5 / 9;

// the formula to change Fahrenheit to Celsius can be found in the following link

int tempe = (int)temperatureC;

// casting into integer

Since the “sendWordPacket” function in arxrobot_firmware requires integer input, the float type must be changed to integer. “sendWordPacket” function packages the output temperature and sends the value to the Arxterra control panel.

The code should output an integer temperature and oxygen values in every minute. For implementation into arxrobot_firmware, comment the void setup and move the code within void loop to the last part of the “sendData()” function under the “telemetry” tab in arxrobot_firmware.

For more details, please refer to github.

 

Pulse Sensor:

Before implementing the Arduino code to arxrobot_firmware, the following lines must be included in the top of the code:

#define TRUE   1

#define FALSE  0

#define debug     TRUE

#define aTechTop   TRUE

Next, the “delay” function must be changed into the “millis” function. For the pulse sensor, it was decided to send heart activity data every quarter of a minute, which can be implemented using millis function as the following line:

unsigned long nextPulseReading = millis() + 15000;

Then, an if statement is used to check for whether quarter of a minute has passed. If a quarter of a minute has passed, the number for beats per minute will be printed on the serial monitor window. Since beats per minute is already an integer number, no casting is needed. Also, the Processing function must be removed from the code.

At this point, the code should look like this:

#define TRUE   1

#define FALSE  0

#define debug     TRUE

#define aTechTop   TRUE

unsigned long nextPulseReading = millis() + 15000;

//  VARIABLES

// Original pulse sensor code can be found in the following link

void setup(){

}

void loop(){

#if aTechTop

if(millis() > nextPulseReading){

nextPulseReading = millis() + 15000;

if (QS == true){

QS = false;

}

#if debug

Serial.println(BPM);

#endif

}

#endif

}

The code should now output beats per minute every quarter of a minute.

To implement into arxrobot_firmware, move the code within void loop to the last part of the “sendData()” function under the “telemetry” tab in arxrobot_firmware. Since the Interrupt setup is in the void setup, rename the void setup to “void setup_pulsesensor()”, which contains the “interruptSetup()” function in it.

For more details, please refer to github.

 

Accelerometer and Body Orientation Sensor:

Before implementing the Arduino code to arxrobot_firmware, the following lines must be included in the top of the code:

#define TRUE  1
#define FALSE 1
#define debug      TRUE
#define aTechTop   TRUE

The “delay” function must then be exchanged with the “millis” function as the delay function will stop the entire arxrobot_firmware. An if statement must be set up to check whether the desired time has passed by. The following step for testing before implementing into arxrobot_firmware is casting. Since the “sendWordPacket” function in arxrobot_firmware requires integer input, the float type must be changed to integer.

To implement into arxrobot_firmware, rename the void setup to “void setup_accelerometer()”, then move the code within void loop to the last part of the “sendData()” function under the “telemetry” tab in arxrobot_firmware.

For more details, please refer to github.

ATECHTOP Project Requirements Verification

Of ATECHTOP’s 22 project requirements, 19 were successfully verified.  The 3 requirements that were not met pertained to the Arxterra control panel.  The ATECHTOP specific control panel modifications were discussed with Arxterra’s webmaster, Jeff Gomes, early on in the semester.  The conclusion was that the modifications would be integrated into Arxterra at a later time.  We will conclude the semester with these suggestions for further ATECHTOP and Arxterra development.

 

ATECHTOP Project Requirements Verification

 

Name:  Shiela Caridad Date: May 08, 2015

 

Project Level 1 Requirement Pass Fail
1.  Must complete a wearable body network by May 8th 2015: the last week of the CSULB Spring 2015 Semester, with the ability to monitor blood oxygen levels, heart activity, temperature, and body orientation wirelessly.
Comments:Verification tests were completed on or before May 8th, 2015. 
2.  The body area network should be able to transfer biometric information from sensor suite wirelessly to Android phone with a transmission range of at least 1.7 meters.
Comments:Verification was successful.  Transfer of physiological signals was measured over a span of 2.5 meters (well in excess of the project requirements.) 
3.  Physiological signals must be transmitted wirelessly to the Arxterra control center.
Comments:Verification was successful. 
4.  From a full charge, energy allocation and source must provide at least 30.2 minutes of continuous monitoring and data transfer as according to the Center for Public Education’s polled average amount of time allocated to play in public schools.
Comments:Verification was successful. 
5.  The complete body network should not exceed 2.9 lbs.
Comments:Verification was successful.  The total weight of the project is 0.617 pounds. 
6.  Cost must be limited to 100$ per project member.
Comments:Verification was successful.  The total cost to each member was $39.09
7.  Keeping with the goals of the senior design project class, Arxterra will provide the online interface through which parents, doctors, or chaperones will monitor their child’s vital signs.
Comments:Verification was successful. 
8.  Any heat generated by use of the device should be below 45° Celsius (113° Fahrenheit) in accordance with burn injury research: This threshold allows for two hours of direct skin exposure time with no greater than 2nd degree reversible skin damage.
Comments:Verification was successful. 
9.  Child should be able to maintain personal full range of motion while wearing the body network.
Comments:Verification was successful. 

 

 

 

 

Project Level 2 Requirement Pass Fail
1.  In order for project to stay within budget and meet deadline requirements, no purchases may be made for items outside of the United States.
Comments:Verification was successful. 
2.  Purchases cannot be made for sensors which need to be manufactured before shipping in order to meet deadline requirements.
Comments:Verification was successful. 
3.  Sensor location for the ECG and pulse oximeter will be placed on each earlobe.
Comments:Verification was successful. 
4.  Most common skin irritants caused by allergic reactions to materials include: latex, formaldehyde resins (used to make fabrics waterproof), exposed elastic, and dispersal dyes which include azo and anthraquinone structures. The wearable body network will reflect understanding of these common allergies by not including them in the design.
Comments:Verification was successful. 
5.  The Arduino computing platform will be used because it possesses the needed capabilities to interact with the Arxterra website, students have experience working with Arduino devices, and also it has wearable properties.
Comments:Verification was successful. 
6.  Electrocardiogram sensor must provide an accurate enough representation of a user’s signals such that an observer on the Arxterra website will be able to determine with 100% accuracy the difference between an individual’s physiological signals at rest and after physical strain.
Comments:
Verification was successful.  A spike in heart rate is easily detected but the highest heart rate was not displayed on an appropriately labeled meter.
7.  Bluetooth, IEEE 802.15.1 standard will be used as the wireless method of communication between the Arduino and Android phone due to its simplicity interacting with both the Android phone and the Arduino platform.
Comments:
Verification was successful.
8.  Batteries will be used to power the body network wirelessly for a period of at least 30.2 minutes at a time without needing recharge or replacement.
Comments:
Verification was successful.
9.  Programming for the project will be implemented in Arduino IDE for its ease of interaction with Arduino hardware.
Comments:
Verification was successful.
10.  In order for the project to stay within budget and meet deadline requirements, a shield for sensors to communicate with the Arduino will be custom-designed by group members.
Comments:
Verification was successful.
11.  Pulse, body temperature, and blood oxygen levels must be clearly presented and updated in real-time on the Arxterra website and mobile application.
Comments:
Physiological signals are transmitted correctly but due to the capabilities of Arxterra, the signals are not accurately labeled.
12.  An alert must be sent to the parent whenever vital sign measurements read as “unsafe” (as defined by settings in the Arxterra app).
Comments:
Arxterra is currently unequipped for this feature.
13.  Arxterra’s alert settings will be password protected. Only parent and physician will have altering access to Arxterra’s alert settings.
Comments:
Arxterra is currently unequipped for this feature.

 

 

Design Evolution of ATECHTOP

By Robyn Goss : ATECHTOP Project Manager

The initial ATECHTOP design was loosely based off of the biometric smartwear designed by OMSignal. OMsignal’s largest objective is the gathering and interpretation of biological signals to turn these into usable feedback for insight. [OMsignal introduction] The apparel is capable of monitoring heart rate and breathing activity while an app displays signals when “distress” is detected.

Fitness_Shortsleeve_BlackOrange_grande

Image source

The intent was for ATECHTOP was the design of an athletic T-shirt with sensors sewn into the shirt using pockets running horizontally around the mid-section and also pockets running vertically along the spine.

Sewn along the horizontal midline were to be:

  • Arduino Lilypad
  • Accelerometer sensor
  • Battery to power sensors

Sewn vertically along the spine were to be:

  • Custom PCB
  • ECG sensor (reaches to earlobe)
  • Pulse Oximeter sensor (reaches to earlobe)
  • Phone
  • Temperature sensor (reaches to armpit)

The final ATECHTOP design was changed to make the product more marketable.The final design utilizes a chest harness rather than an athletic shirt design.

Advantages of harness:

  • Child will not grow out of harness as it is adjustable
  • Will fit a variety of sizes and ages- will not limit
  • Washable
  • Individual style is not limited as the child can wear whatever is desired over the harness
  • Can attach GoPro to frontside of the harness if parent desires

Disadvantages of shirt:

      • Dirties quickly
      • Limits child’s choice of clothing
      • Fit might not be right for every child
      • As child grows, the child will need to purchase an entirely new shirt
      • Less conspicuous

The following image reveals the expected look of the chest harness with exception of the sensors and straps. The frontside of the harness will carry the phone, and the backside will carry the sensors, PCB, Lilypad, and battery of the sensor suite.

sheila1

sheila2

The following image demonstrates a five year old boy wearing the ATECHTOP sensor suite. There are four pockets along the back straps: two along the spine and three (or two additionally) along the midline. The three pockets along the midline contain respectively from left to right: the accelerometer and bluetooth module, the Arduino Lilypad, and the battery power supply. The two pockets along the spine contain respectively from top to bottom: the custom PCB design and the Arduino Lilypad.

20150515_140939

This above image details the final design of the ATECHTOP Sensor Suite.

 

 

Verification Testing: Materials Compliance

By Shiela Caridad : ATECHTOP Mission Systems and Test Engineer

Edited and approved by Robyn Goss : ATECHTOP Project Manager

 

Objective

The purpose of this test is to verify that ATECHTOP has adhered to the requirements concerning common skin irritants.

Procedure

  1. A group member will take note of all materials used in the manufacturing of the wearable portion of the project.
  2. The materials will be noted in the appropriate data sheet and will be verified against the mission requirements, which specify against common skin irritants.

The results of this verification will ensure compliance with the following mission requirements:

Project Level 2 Requirement #4:  Most common skin irritants caused by allergic reactions to materials include: latex, formaldehyde resins, exposed elastic, and dispersal dyes which include azo and anthraquinone structures. The wearable body network will reflect understanding of these common allergies by not including them in the design.

NOTE:  Project requirements are as listed in the Project Requirements blog post.

Results

After conducting this verification test, we found that our project does adhere to the mission requirements.  The main wearable component of the project is the chest harness, which is comprised of a cotton and lycra blend.  Upon further research, we found that the dye most commonly used for lycra is direct/acid dyes.  These dyes are not restricted by the mission requirements.

Verification Data Sheet: Wearable Materials

Name: Shiela Caridad Date: May 5, 2015

 

List all materials used for wearables: 

Spandex

Plastic
Lycra
Cotton
Dyes used for Spandex/Lycra/Cotton are “Direct” or a combination of “Direct” and Acid dyes

 

Does this list include any materials which are prohibited by the mission requirement? No

5

Development of a Printed Circuit Board

By Kenia Garcia : ATECHTOP Electronics Engineer

Edited and approved by Robyn Goss : ATECHTOP Project Manager

The wearable body network will include a printed circuit board, which includes the temperature and pulse-oximeter circuitry. The PCB serves as a hub for all sensors, allowing for a neater connection to the Lilypad Arduino. The centralization of the sensors prior to connecting to the Lilypad is necessary in order to minimize wiring clutter.

Schematic

The schematic of the ATECHTOP PCB is described in figure 1.  The PCB consists of three 220 ohms resistors, phototransistor, red led, infrared and a total of 24 pins. 13 pins are used to connect the sensors to the PCB and the other 11 pins to connect to the Lilypad.

1figure 1

Board Layout

Eagle Cad software along with Sparkfun tutorials were used to make the schematic and the BRD file.  Building the schematic was not difficult but rather tedious: it was a bit time consuming trying to find particular components within the library. The link to the schematic and the BRD tutorial can be accessed below.

2

figure 2

The first draft is seen in figure 2. This board is a single layer board 1.3 x 2 inches. The board was modified mainly for the reason that it did not resemble the selected microcontroller board. The board was reshaped to closer resemble the Lilypad. This second and final draft is seen in figure 3:

3

figure 3

Manufacturing

After looking into various manufacturing PCB companies, OSH Park was selected as the ATECHTOP PCB manufacturing site. The pricing and expected shipment time worked perfectly within the schedule requirements. It took approximately 12 days from the moment files were sent to the manufacturer the the date the PCB(s) arrived.

The cost was less than $17 for 3 boards. Other companies charged at least $30 per board.  The actual boards are shown in figure 4 below:

4

figure 4

References: 

[1] Schematic tutorial

[2] BRD tutorial

[3] PCB manufacturing site