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Simple Lie Detector

Discussion in 'Electronic Projects' started by ElectroMaster, Jul 19, 2002.

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  1. spy_genius

    spy_genius New Member

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    What about the analog meter.Is there any substitution for that.Please post your replies at the earliest.Because i need to do this for my project.
     
  2. nemalipuripraveen

    nemalipuripraveen New Member

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    about electrodes

    hi, :D
    ]i want to say that ur project is simply amazing.I would like to do this project and in this regard i'd need ur help about electrodes... can they be simple wires if so, if we connect those wires to the hands of the subject..is there any shock to the subject?? if it does what r the precaution to avoid shock. plz rpl early so that i can do the project
    thanks u once again...
     
  3. akg

    akg New Member

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    Re: about electrodes

    electrode contacts are availabe at medical lab: supplies , that make good contact with skin
     
  4. dave

    Dave New Member

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  5. Passn_thru2

    Passn_thru2 New Member

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    there is 0-1mA analog panel meter for $10.95 part #01MAO-1 at http://www.elexp.com/tst_mamo.htm, where were they for $5.??

    this is a GSR meter, very neat thing.. the electrodes are usually attached to the index and middle finger, i have been looking for the velco ones with the wires attached and a plug..they can be made out of stainless steal washers, if it is possable to solder a copper wire in them..Hmmm i dont recall if you can solder stainless.?? and wrap velcro around them snugly on your fingers. i have an elestac wrist strap with quater size crome domed buttons, but i dont reall like it. i have a program for the PC where you move an image like a ballon across a picture and land it on a target by changing specific Brainwave levels to move it horozontally and vertically without thinking about it.

    If anyone is familure with Scientology, and i am NOT recomending them or their practaces to anyone, they have a special magoc meter where they have you hold to cylendars and they "Condition" with it ..it is a GSR meter.
    I used GSR in Behavior Modification Classes, Alcohol Addiction and Anger Management.

    the comercial units have a (+) or (-) pezio sound option where it buzzes when your hit your target level or stops buzzing, set with a moveable red line.

    i need to locate plans for a meter that reads the electrical impulses of the muscles, to make a meter that indicates when you are unconsciously vocalizing when you are reading.. you can increase your Words pr Minute by a factor of 500% to over 800% by hearing the beep when you think of the word and unconsciously vocalize it.. it is a very useful tool when teaching children to read. i forget what it is called.
     
  6. Passn_thru2

    Passn_thru2 New Member

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    electrodes are electrical conductors, which are a metal or plated with a metal that doesnt corode or tarnish from the salt in the skin/although you couls polish something with some wet and dry sand paper each time. you might try soldering the lead wires on a plated tack and bending over the pin part after pushing it thru the velcro then bending it over to hold it in place. thevelcro is a piece about 1.5X longer than it takes to wrap around a finger/fury side up with a 1/2 in piece of the hoop side glued or sewn on top of one end to lock it down. try it on index and middle finger

    the GSR meter measures how much electricity is conducted between the electrodes, in this case it is actually how much sweat is present which contains salt, more sweat=more salt which is a conductor of the electricity flowing form one of the conductors/electrodes to the other, that is why there is battery in the unit, it supplies the current which is read by the meter.

    this is a really fun thing at parties.. you ask an embarising question for which the embarising answer will result in a higher reading.. proving it true. when one gets emotional the sweat glands release salt increasng the flow of electricity between the electrodes.

    the trick is to keep them calm till you put the question to them.
     
  7. Roff

    Roff Well-Known Member

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    I posted this variation of the lie detector here.
    As was noted above, you can use almost any small-signal transistor, such as the ubiquitous 2N3904.
     

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    Last edited by a moderator: Dec 26, 2013
  8. chemelec

    chemelec Well-Known Member

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    It should also be noted that In doing this kind of testing, The person should ask a number of easy questions, getting Correct answers and resulting in "No needle movement".

    Such as:
    What is the persons name?
    What is your age?

    Also get the person to purposely lie on a few sample questions.

    This somewhat helps Eliminate False readings from the person Just being Scared.

    This circuit has been around for many years. I think at least 30 years in a "popular electronics magazine" or simular type magazine.

    And Meters with Greater Sensitivity than 0 to 1 mA can be used, resuling in Greater variation on lies. Such as a 100 uA Meter.
     
  9. Freedom Conquer

    Freedom Conquer New Member

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    Thank you very much i needed that for my small deploma project
     
  10. panic mode

    panic mode Well-Known Member

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    also changing transistor to PNP and reversing polarity of C1, M1 and battery will convert it to truth detector :wink:
     
  11. Roff

    Roff Well-Known Member

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    :lol: :lol: :lol:

    When you tell the truth, sweat (moisture and salt) gets sucked back into your sweat glands. I'm told that, if you are ever caught in a thunderstorm, you should recite every truth you know. This will increase your skin resistance and make you immune to lightning. Unless it's raining.
     
  12. theinfamousbob

    theinfamousbob Member

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    Maybe that's why golfers always get struck on the fairway....too busy lying about the drive... :lol:
     
  13. Roff

    Roff Well-Known Member

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    :lol: :lol:
     
  14. gaith

    gaith New Member

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    plz help i didnt understand where the wire join to the r2 risisteor :cry: :cry: :cry: :cry: :cry: :cry:
     
  15. akg

    akg New Member

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    R2 is a variable resistor(trim pot) , it has 3 legs , the arrow shown is the middle terminal of the variable resistor.
     
  16. nikhil_nrao

    nikhil_nrao New Member

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    Re: Details of Parts

    please give me a substitution for the transistor :D
     
  17. Roff

    Roff Well-Known Member

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    Re: Details of Parts

    You can use any general purpose, small-signal NPN. I would use 2N3904, but there are many other suitable transistors available.
     
  18. electroniks

    electroniks New Member

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    How can I connect the transimpedance amplifier (attached) to the circuit above so the reading can be done with more ease?
     

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  19. haka

    haka New Member

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    someone can telling me how does it work? cos i not so clear about it working.. hehe..
    can use msn chat with me?
    ljung_ng@hotmail.com
    thx...
     
  20. akg

    akg New Member

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    read the first post
     
  21. electroniks

    electroniks New Member

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    Anyone know how I can attach the transimpedance amp to that circiut? (2 posts above)

    Thanx.
     
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