Portable Lie Detector Test
Recently, a gadget called “Portable Lie Detector” was caught, which, according to the sellers, quite decently determines the presence of untruth in the answers and hurts him with a current. 
After the office identified individuals who were shocked with questions like “Do you cheat on your wife?”, “Do you cheat on your superiors?”, “Do you dream of having sex with men?”, Etc., gadget I went to all the friends and parties I have been to.
I want to say that people slanted in different ways: someone was already falling on the first question, and one girl (really truthful dandelion) lasted 23 questions without strikes, but grabbed on the question: “Do you steal money from your parents?”.
All the testers had reasonable doubts - but doesn’t it happen to randomly shake the device with a current and accuse them of lying? In principle, it was rather difficult to find out in an empirical way: someone admitted that he had been struck on the case, and someone had complained that he had been hurt by the “truth”.
One day, a couple of friends visited me. Not in the sense that there were two of them, but in the plan that they are a pair of m + f. This visit ended with a rather powerful scandal, and all thanks to this lie detector. It all started, as usual fun:
- you are cheating on me?
-Not! (true).
Do you love me?
-Yes true).
……
- Do you respect my parents?
-Yes! (Tykyzh shock!).
They giggled and decided to check again:
"Is your name that way?"
-Yes true).
-Do you have so many years?
-Yes true).
- Do you respect my parents?
-Yes (Tydyzh current!)
And in this vein, another 17 (!!!!) times the girl jumped on this very question. The guys had a reason to talk about their relationship, and I had a firm conviction that the device was shaking away from random access. Such coincidences simply could not be.
Deciding to sort out this issue, I went to the Internet and get a screwdriver.
To begin with, a couple of dozen pages of information about the principles of the work of “adult” polygraphs were studied. As a result, it was found that polygraphs monitor several human indicators: respiration, cardiovascular activity, electrical resistance of the skin (according to wikipedia).
')
To begin with, in order to understand which of these (or which of these) parameters my pocket polygraph probably takes into account, I took it apart. See photo below:
In the photo: 1 - reset button, 2 - initial calibration button and analysis start button, 3 - true scale, 4 - contacts, 5 - strap.
Inside, I found 1 chip and a speaker, which was responsible for the sinister sounds made by my polygraph. I made a logical conclusion and suggested that the chip is responsible for determining the wrong. According to the number (M2080A1) I found this scheme in pdf format — you can download it . Having completely forgotten the circuitry that I so diligently taught for 6 years at MEPI, I scored on the scheme and began to think logically. Looking at how, from where, where and what wires go, I concluded that this device is not capable of measuring cardiovascular activity and respiration at all. It would be more wires, and the scheme would be more difficult. To test my hypothesis, I armed myself with a heart rate monitor and began to be checked on the detector and look at the dependence of the scale on the pulse.
In the normal state, my pulse was 88 u. While I was answering standard questions like “What is your name, where do you live?”, The pulse almost did not change, and the device stubbornly showed “one” on the truth scale. Then I began to increase the pulse (squat there, breathe quickly). On the pulse in 98-105, the device began to show a “two” on a scale. On the pulse at 120, he showed a “troika”, but he didn’t want to beat me hard. The changes in my "cardiovascular activity" were very strong, but the detector almost did not react to them. At least not to the extent that it should. Consequently, my hypothesis was confirmed.
The only option left is the electrical resistance of the skin.
Electrical resistance is a scalar physical quantity that characterizes the properties of a conductor and is equal to the ratio of the voltage at the ends of the conductor to the strength of the electric current flowing through it.
That is, the principle of the polygraph on the resistance is as follows: a constant small current (not sensitive at all) is passed through the object (body), so you can understand and record when the resistance of the conductor changes.
And according to one hypothesis, when a person lies, physiological processes occur in his body that affect the conductivity of his body.
Judging by the scheme and wiring, this type of measurement is quite within the power of this device!
Since I could not figure out exactly how to influence the resistance of my body, I could not be 100% sure that it determines the lie according to this indicator. If someone has any suggestions, I will be glad to hear and test!
P.S. All testers had the impression that there was a certain dependence on the degree of moisture of the hands.
P.P.S. In general, he really well defines a lie, subject to the necessary conditions of research on a polygraph - in silence, without distractions. In general, seriously. After all, if all this happens in a joking manner, and the person has a fairly strong nervous system and healthy refusing, it is hard enough to “light up”, unless the question forces him to really press the buttocks!
After the office identified individuals who were shocked with questions like “Do you cheat on your wife?”, “Do you cheat on your superiors?”, “Do you dream of having sex with men?”, Etc., gadget I went to all the friends and parties I have been to.
I want to say that people slanted in different ways: someone was already falling on the first question, and one girl (really truthful dandelion) lasted 23 questions without strikes, but grabbed on the question: “Do you steal money from your parents?”.
All the testers had reasonable doubts - but doesn’t it happen to randomly shake the device with a current and accuse them of lying? In principle, it was rather difficult to find out in an empirical way: someone admitted that he had been struck on the case, and someone had complained that he had been hurt by the “truth”.
One day, a couple of friends visited me. Not in the sense that there were two of them, but in the plan that they are a pair of m + f. This visit ended with a rather powerful scandal, and all thanks to this lie detector. It all started, as usual fun:
- you are cheating on me?
-Not! (true).
Do you love me?
-Yes true).
……
- Do you respect my parents?
-Yes! (Tykyzh shock!).
They giggled and decided to check again:
"Is your name that way?"
-Yes true).
-Do you have so many years?
-Yes true).
- Do you respect my parents?
-Yes (Tydyzh current!)
And in this vein, another 17 (!!!!) times the girl jumped on this very question. The guys had a reason to talk about their relationship, and I had a firm conviction that the device was shaking away from random access. Such coincidences simply could not be.
Deciding to sort out this issue, I went to the Internet and get a screwdriver.
To begin with, a couple of dozen pages of information about the principles of the work of “adult” polygraphs were studied. As a result, it was found that polygraphs monitor several human indicators: respiration, cardiovascular activity, electrical resistance of the skin (according to wikipedia).
')
To begin with, in order to understand which of these (or which of these) parameters my pocket polygraph probably takes into account, I took it apart. See photo below:
In the photo: 1 - reset button, 2 - initial calibration button and analysis start button, 3 - true scale, 4 - contacts, 5 - strap.
Inside, I found 1 chip and a speaker, which was responsible for the sinister sounds made by my polygraph. I made a logical conclusion and suggested that the chip is responsible for determining the wrong. According to the number (M2080A1) I found this scheme in pdf format — you can download it . Having completely forgotten the circuitry that I so diligently taught for 6 years at MEPI, I scored on the scheme and began to think logically. Looking at how, from where, where and what wires go, I concluded that this device is not capable of measuring cardiovascular activity and respiration at all. It would be more wires, and the scheme would be more difficult. To test my hypothesis, I armed myself with a heart rate monitor and began to be checked on the detector and look at the dependence of the scale on the pulse.
In the normal state, my pulse was 88 u. While I was answering standard questions like “What is your name, where do you live?”, The pulse almost did not change, and the device stubbornly showed “one” on the truth scale. Then I began to increase the pulse (squat there, breathe quickly). On the pulse in 98-105, the device began to show a “two” on a scale. On the pulse at 120, he showed a “troika”, but he didn’t want to beat me hard. The changes in my "cardiovascular activity" were very strong, but the detector almost did not react to them. At least not to the extent that it should. Consequently, my hypothesis was confirmed.
The only option left is the electrical resistance of the skin.
Electrical resistance is a scalar physical quantity that characterizes the properties of a conductor and is equal to the ratio of the voltage at the ends of the conductor to the strength of the electric current flowing through it.
That is, the principle of the polygraph on the resistance is as follows: a constant small current (not sensitive at all) is passed through the object (body), so you can understand and record when the resistance of the conductor changes.
And according to one hypothesis, when a person lies, physiological processes occur in his body that affect the conductivity of his body.
Judging by the scheme and wiring, this type of measurement is quite within the power of this device!
Since I could not figure out exactly how to influence the resistance of my body, I could not be 100% sure that it determines the lie according to this indicator. If someone has any suggestions, I will be glad to hear and test!
P.S. All testers had the impression that there was a certain dependence on the degree of moisture of the hands.
P.P.S. In general, he really well defines a lie, subject to the necessary conditions of research on a polygraph - in silence, without distractions. In general, seriously. After all, if all this happens in a joking manner, and the person has a fairly strong nervous system and healthy refusing, it is hard enough to “light up”, unless the question forces him to really press the buttocks!
Source: https://habr.com/ru/post/88423/
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