1 / 20

THE LIE DETECTOR

THE LIE DETECTOR. Tim Fleck Mike Gruener Brian Halaburka Chris Moskaites. OBJECTIVES.

boaz
Download Presentation

THE LIE DETECTOR

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. THE LIE DETECTOR Tim Fleck Mike Gruener Brian Halaburka Chris Moskaites

  2. OBJECTIVES • To create a sensing device modeled after a polygraph test • Test would incorporate results from several physiological sensors • Create a Labview program to gather and analyze subject data

  3. POLYGRAPH THEORY • Polygraphs measure: • Heart rate • Respiratory rate • Blood pressure • Arm and leg motion • Electrodermal activity

  4. INITIAL IDEAS • Use real world polygraphs as design models • Assemble a polygraph which monitors heart rate, breathing rate and electrodermal activity • Create a Labview program which would self-analyze data and “detect” deceptive behavior

  5. FINAL LIE DETECTOR • Incorporates two physiological sensors detecting two phenomenon 1)electrodermal activity 2)motion • Self analyzes received data

  6. DETECTOR LOGIC Subject Electrodermal Sensor/Motion Sensor DAQ New Data LABVIEW/CPU Display Results

  7. SENSORS • Electrocardiogram or EKG • Galvanic Skin Response Sensor

  8. ELECTROCARDIOGRAM • Measures the electrical activity of the heart • Determines hearts rate and rhythm • Our project used it to measure motion

  9. GALVANIC SKIN RESPONSE SENSOR • Senses moisture • Stand-alone unit • Produces noise • Frequency was too fast for the DAQ

  10. CREATED SKIN SENSOR • Based off the idea that skin resistance decreases with moisture • Used a voltage difference circuit • Amplified the voltage difference to obtain obvious results

  11. LABVIEW LOGIC (EKG) • Take initial readings visually from the waveform graph • Calibrate the high and low end of the threshold based on the initial readings • Every question after will be compared to the threshold • If a person’s motions go above the threshold, a LED goes on, indicating a lie

  12. LABVIEW LOGIC (GSR) • Takes voltage readings of subject’s fingers until button is pushed • Then it computes and displays and average voltage for the given time period • Displays a waveform chart showing how much the subject’s voltage is increasing from the average as resistance decreases • If the in average increase goes above a certain predetermined value, a light goes on, indicating a lie

  13. DATA • Thresholds were determined by analyzing results gathered from group testing • Normalized against predetermined values

  14. DATA ANALYSIS AND RESULTS Galvanic Sensor: • Computes voltage average • Determines a lie if the subject’s voltage goes above a threshold

  15. DATA ANALYSIS AND RESULTS EKG: • Displays the electrical impulses generated by a human body • When a certain level of voltage is generated in the body it rises above a predetermined value indicating irregular behavior • Detects movements from bodily extremities, specifically the arms and legs

  16. NORMAL EKG WAVEFORM

  17. DECEPTIVE WAVEFORM

  18. SOURCES OF ERROR • Nervousness of test subject • Calibration errors

  19. Difficulties • Heart Rate Monitor • Galvanic Skin Response • LABVIEW • Lab Setup

  20. CONCLUSIONS • “Simple” circuitry increases in complexity once work begins • Check and recheck components before and after assembly • Start early • Be flexible and constantly improve

More Related