60 Hertz Electromagnetic Field
Detector/Interface System
UIUC ECE 445, Spring 2012 – Team #13
3 Segments of this Presentation
Team Members: Gaurav Jaina, Bhaskar Vaidya, Kuei-Cheng Hsiang
Introduction Engineering
Pro...
Introduction
Background, Objectives & Initial Design Thoughts
Mr. Jamie Norton came up to us with a
unique project requiring us to build a user
friendly device which would have applica...
Project Objectives
What was required?
• A 60-Hertz electromagnetic radiation detection device
• Greater Sensitivity, Porta...
Features
• Static 3-axis coil configuration for detection of all polarizations
• Detection of electromagnetic radiation be...
Plan & Block Diagram
After a few brainstorming sessions amongst ourselves,
meetings with Jamie and consulting with profess...
Engineering Process
Final Design Choices, Justification, Hardware development
After finalizing the block diagram
we went on to design each
module and develop the
necessary hardware for it.
The next fe...
Antenna’s
• Coils hand-wrapped around ferrite cores
• Wooden stoppers to preserve shape
• Counting Error  More turns than...
Filter Design
• Two-pole active band-pass filter
• Center Frequency:60Hz
• A single Supply Design
• 3 dB Bandwidth: 10Hz
•...
Filter Schematic
Actual Filter Circuit
Software (Input)
• Intensity detection routine
– Sampling over ~2 periods (34ms)
– Vector sum of maximum intensities from
...
Software (Output)
• Driving micro-transducer array
– Number of high digital outputs corresponds to
intensity of field
• Sa...
Micro-transducer Array
• Driven by BJT array
– Controlled by Arduino outputs
• Mounted on self-made wristband
– Vinyl band...
User Interface Picture
• Interweaved rubber and tape for
vibration damping
• Velcro for adjustable size
• Disconnecting, 8...
Final Project Analysis
Tests, Successes, Challenges, Ethical considerations and Recommendations
Putting it all together
Test Procedures
Antenna
• The detection coils
were placed in a
Helmholtz coil
generating a constant
60 Hertz magnetic
fiel...
Antenna tests and results
0
20
40
60
80
100
120
140
160
180
Coil 1
Coil 2
Coil 3
mV
uT
A graph Showing Voltage Induced vs ...
Filter tests and results
• Adjustment in filter gain
• Testing using proto-board before PCB
• Lack of exact required resis...
Filter tests and results
Channel#1 Channel#2 Channel#3
Vin (mV)
Vin_actual
(Vm) Vout (Vm) Vin (mV)
Vin_actual
(Vm) Vout (V...
Test Procedures
Microcontroller
• The robustness of
the code was
tested by
outputting serial
data regarding the
detected
a...
Full System test
Chart shows input current and corresponding magnetic field levels, and the number of
micro-transducers tu...
We commit ourselves to abide by the ethical
code laid down by the IEEE. A few
considerations specific to our project are :...
Recommendations for future work
Tunable Filter
More compact case
Different user-interface
Larger size array using better t...
From All of us
All peer reviewers
Everyone at the parts shop
Prof. Doug Jones
Prof. J.T. Bernhard
Dr. Serge Minin
Jack Bop...
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60 hz Electromagnetic Field Detection-Interface System

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Senior Design Project, Department of Electrical & Computer Engineering, University of Illinois, 2012.

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Transcript of "60 hz Electromagnetic Field Detection-Interface System"

  1. 1. 60 Hertz Electromagnetic Field Detector/Interface System UIUC ECE 445, Spring 2012 – Team #13
  2. 2. 3 Segments of this Presentation Team Members: Gaurav Jaina, Bhaskar Vaidya, Kuei-Cheng Hsiang Introduction Engineering Process Final Project Analysis
  3. 3. Introduction Background, Objectives & Initial Design Thoughts
  4. 4. Mr. Jamie Norton came up to us with a unique project requiring us to build a user friendly device which would have applications in neuroscience . Working with a different department and the potential for further research is what attracted us most to this project. Background Our Project
  5. 5. Project Objectives What was required? • A 60-Hertz electromagnetic radiation detection device • Greater Sensitivity, Portability, and user-friendliness than previous designs • Integrated Haptic Feedback Why do we need it? • To detect ambient noise that decreases SNR of EEG Machines • It has potential research applications in Brain-Machine interfacing and the development of new senses
  6. 6. Features • Static 3-axis coil configuration for detection of all polarizations • Detection of electromagnetic radiation between 55 and 65 Hertz • Compact, portable design • Haptic feedback user interface • Filter with in built amplifier and rectifier to reduce number of parts used.
  7. 7. Plan & Block Diagram After a few brainstorming sessions amongst ourselves, meetings with Jamie and consulting with professors, we came up with the following block diagram which we stuck with to the end.
  8. 8. Engineering Process Final Design Choices, Justification, Hardware development
  9. 9. After finalizing the block diagram we went on to design each module and develop the necessary hardware for it. The next few slides will discuss each individual design choice. Moving ahead Step 2 : Making it all
  10. 10. Antenna’s • Coils hand-wrapped around ferrite cores • Wooden stoppers to preserve shape • Counting Error  More turns than expected - Adjustment in filter gain
  11. 11. Filter Design • Two-pole active band-pass filter • Center Frequency:60Hz • A single Supply Design • 3 dB Bandwidth: 10Hz • Power Supply: 6V • Desired Gain: 200 V/V
  12. 12. Filter Schematic
  13. 13. Actual Filter Circuit
  14. 14. Software (Input) • Intensity detection routine – Sampling over ~2 periods (34ms) – Vector sum of maximum intensities from each channel
  15. 15. Software (Output) • Driving micro-transducer array – Number of high digital outputs corresponds to intensity of field • Saturation Handling – Single coil saturates  Feedback unit pulses
  16. 16. Micro-transducer Array • Driven by BJT array – Controlled by Arduino outputs • Mounted on self-made wristband – Vinyl band with mounted project box • Four above wrist, four below • Low Resolution, High Intuitiveness – Sense of touch – Mapping
  17. 17. User Interface Picture • Interweaved rubber and tape for vibration damping • Velcro for adjustable size • Disconnecting, 8 conductor cable for ease of use
  18. 18. Final Project Analysis Tests, Successes, Challenges, Ethical considerations and Recommendations
  19. 19. Putting it all together
  20. 20. Test Procedures Antenna • The detection coils were placed in a Helmholtz coil generating a constant 60 Hertz magnetic field. The induced response was measured using an oscilloscope. Filter • Each channel was swept with 60 Hertz waveforms to characterize the gain. The frequency was also varied around 60 Hertz to characterize the bandwidth
  21. 21. Antenna tests and results 0 20 40 60 80 100 120 140 160 180 Coil 1 Coil 2 Coil 3 mV uT A graph Showing Voltage Induced vs Magnetic Field for each coil separately
  22. 22. Filter tests and results • Adjustment in filter gain • Testing using proto-board before PCB • Lack of exact required resistances  pass-band offset to one side • Increased bandwidth in design • Diode nonlinearities • Converted to single-supply
  23. 23. Filter tests and results Channel#1 Channel#2 Channel#3 Vin (mV) Vin_actual (Vm) Vout (Vm) Vin (mV) Vin_actual (Vm) Vout (Vm) Vin (mV) Vin_actual (Vm) Vout (Vm) 0 1.313 120 0 1.72 135.9 0 3.28 135 1 2.813 171.9 1 2.81 253 1 5.16 287 2 3.75 453 2 3.91 315.6 2 6.56 306 3 4.188 581 3 6.56 472 3 5.94 481 4 5 793.8 4 7.97 675 4 8.31 668 5 6.375 850 5 9.69 1019 5 9.22 1063 10 11.72 1766 10 14.69 1950 10 14.38 1953 15 16.09 2250 15 20.31 2310 15 18.63 2340 20 23.75 2480 20 24.7 2470 20 23.13 2530 30 32.19 2770 30 36.25 2730 30 35.94 2810 40 43.75 2970 40 44.69 2940 40 45.94 3110 50 54 3130 50 55 3080 50 55.63 3220 60 62.5 3270 60 64 3230 60 66.25 3340 70 75.62 3420 70 75 3350 70 75.62 3440 75 78.75 3450 75 79.37 3500 75 81.88 3500 80 80 3470 80 85.63 3500 80 85.63 3500 Table showing filer test results at 60 Hz. See where it saturates. We noticed that no significant gain was observed outside a 10 Hz window • Gain 1: 163.7 • Gain 2: 175.3 • Gain 3: 140.2
  24. 24. Test Procedures Microcontroller • The robustness of the code was tested by outputting serial data regarding the detected amplitudes to a computer, and comparing with the input waveform. Haptic Feedback • The feedback array contained in the wristband was tested by driving each individual BJT on at a time using the Arduino. Power Supply • The batteries worked properly, only concern is as the 6V source for the op-amps slowly falls in voltage value, the output offset falls with it, and the Arduino code constant for the offset must be adjusted.
  25. 25. Full System test Chart shows input current and corresponding magnetic field levels, and the number of micro-transducers turned on As the table shows, the system can detect magnetic field strengths from around 0.01 uT to around 10 uT. 0 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 Saturation Irms uT
  26. 26. We commit ourselves to abide by the ethical code laid down by the IEEE. A few considerations specific to our project are : » Safety concern - if this device is used in areas of high radiation density. We ensured that currents do not exceed normal levels. » No Ghost Hunting! » Being honest to our clients – No false promises, and keeping the cost in mind. Ethical Considerations
  27. 27. Recommendations for future work Tunable Filter More compact case Different user-interface Larger size array using better transducers Wireless communication sensor & feedback
  28. 28. From All of us All peer reviewers Everyone at the parts shop Prof. Doug Jones Prof. J.T. Bernhard Dr. Serge Minin Jack Boparai TA Ryan May Mr. Jamie Norton Prof. Paul Scott Carney
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