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E-Vest : WIRELESS NON-INVASIVE ECG MONITORING Digital FM Serial transmitter

E-Vest : WIRELESS NON-INVASIVE ECG MONITORING Digital FM Serial transmitter. Faculty Advisor: Dr . Kamesh Namuduri. Mohammed Alsadah Alexander Wright . Department of Electrical Engineering University of North Texas Denton, Texas. Objectives.

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E-Vest : WIRELESS NON-INVASIVE ECG MONITORING Digital FM Serial transmitter

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  1. E-Vest: WIRELESS NON-INVASIVE ECG MONITORINGDigital FM Serial transmitter Faculty Advisor: Dr. KameshNamuduri Mohammed Alsadah Alexander Wright Department of Electrical Engineering University of North Texas Denton, Texas

  2. Objectives • Contemporary Issues • Introduction • Design Consideration • Circuit Design • Hardware/Software Implementation • Reception Information • Testing • Difficulties • Standards & Ethics • Result /Conclusion • Team Work • Further Exploration “Work” • References

  3. Contemporary Issues “ Motivations” • On March 17th 2014, Carmen, a 16 year old Virginia girl dies moments as soon as she completes the half-marathon. • This is our potential goal to save lives and prevent sudden Cardiac Arrest

  4. Fall 2013 : Bluetooth • The Bluetooth frequency range is at 2.4 to 2.485 GHz/ • The distance range is only 100 meters or approximately 328 feet. • Predefined Standard : FCC approved • Low power and Low voltage (3.3V) • Built in Antenna • Encrypted Connection

  5. Introduction • In order to support remote monitoring of EKG signals we need the ability to transmit digital information over long distances in a cheap and efficient manner • We decided to perform FM transmission of digital data through Binary Frequency Shift Keying • In order to minimize cost and complexity we made use of an LC circuit instead of phase locked loop based oscillator • This design will have less frequency stability and higher phase noise than a PLL based system • Goal is to be able to transmit a digital signal at least half mile (805 meters ).

  6. BFSK • Binary Frequency Shift keying • Uses two discrete frequencies vs entire continuous variation range used in FM

  7. FM Circuit

  8. Design • Multiple BJT amplification stages some with feedback • LC Hartley oscillator using hand wound inductors made of enameled magnet wire. • LM566 Voltage Controlled oscillator used to generate square waves for bits through UART connected to an NMOS

  9. Oscillator circuit • Voltage divider of output square wave • NTE2932 NMOS used to switch voltage on pin 5 based on 3.3V TTL signal input

  10. Circuit design • Circuit in the breadboard for the original FM transmitter • Below, the circuit successfully soldered

  11. Hardware/Software Implementation • Interface control documentation

  12. Reception Information Software Defined Radio using Realtek RTL2832U chip • http://sdr.osmocom.org/trac/wiki/rtl-sdr SDR# Software • http://sdrsharp.com/

  13. Testing • Oscilloscope used to verify TTL to square wave conversion SDR# used to verify transmission of square waves

  14. Reception • WinFM software created to decode data images show 0’s and 1’s being received

  15. Difficulties • Ordering components • Lead times, hard to find components • Soldering circuit • Special thanks to Abraham Hasir for helping us • Differences between theoretical values and what provided the results we wanted • likely due to breadboard capacitance/resistances

  16. Standards & Ethics • Standard for medical equipment from ISO/IEEE 11073 • IEEE 1284: UART Serial Communication • UNT Institutional Review Board (IRB) Procedures

  17. Federal Communications Commission • The FCC limits unlicensed FM broadcasts to a maximum signal strength of 250uV/m (microvolts per meter), measured at a distance of 3m--about 10 feet • limiting both the antennae gain and voltage level of the circuit we can control the field strength of the transmitted signal • we have both lowered the voltage and completely eliminated the antennae in order to prevent exceeding these limits.

  18. Result/Conclusion • We have successfully transmitted serial TTL level data using binary frequency shift keying over FM bands using available electronics components. • We believe this project will assist in the remote monitoring of athletes as they compete toward reaching their goals while remaining safe from abnormal heart conditions.

  19. Further Exploration “ work” • Jarvis Jones and I will be designing the Antenna (summer 2014). • Transmits at a carrier frequency of 2.75 GHz using no more than 24 Mhz bandwidth.

  20. References • "Frequency-shift Keying." Wikipedia. Wikimedia Foundation, 15 Mar. 2014. Web. 21 Mar. 2014. <http://en.wikipedia.org/wiki/Frequency-shift_keying>. "Headlines." Home. N.p., n.d. Web. 21 Mar. 2014. <https://www.fcc.gov/>. • Kim, HyoungSoo, Venu Varanasi, Gayatri Mehta, Hualiang Zhang, Tae-Youl Choi, KameshNamuduri, JakobVingren, Nandika Anne D'souza, and Robert Kowal. "Circuits, Systems, and Technologies for Detecting the Onset of Sudden Cardiac Death Through EKG Analysis." IEEE Circuits and Systems Magazine 13.4 (2013): 10-25. Print. • "Virginia Girl, 16, Dies Moments after Finishing Half Marathon ." NY Daily News. Carol Kuruvilla, 17 Mar. 2014. Web. 18 Mar. 2014. <http://www.nydailynews.com/news/national/virginia-teen-16-dies-moments-finishing-marathon-article-1.1725562>.

  21. Questions

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