March 22, 2010 at 13:35Handheld Lie Detector Test
Recently, a gadget called "Portable Lie Detector" fell into my hands, which, according to sellers, pretty decently determines the presence of untruth in the answers and hurts for it with an electric shock. 
After identifying people at the office who were shocked by questions like “are you cheating on your wife?”, “Are you cheating on your bosses?”, “Are you dreaming about sex with men?” etc., the gadget went to all the friends and parties I visited.
I want to say that people shied in different ways: someone rained already on the first question, and one girl (a really truthful dandelion) held out 23 questions without blows, but grabbed the question: "Do you steal money from your parents?"
All the inspectors had reasonable doubts - and is it not by chance that the device spoils the current and accuses it of lying? In principle, it was rather difficult to find this out in an empirical way: someone admitted that he had been hit in the case, while someone complained that he was shy about the “truth”.
One day a couple of friends came to visit me. Not in the sense that there were two of them, but in the sense that they were a couple m + f. This visit ended with a rather powerful scandal, and all thanks to this lie detector. It all started, as usual fun:
- Are you cheating on me?
-Not! (true).
Do you love me?
-Yes true).
.......
-Do you respect my parents?
-Yes! (Surge!).
Giggled and decided to check again:
-Your name is that?
-Yes true).
-You are so many years old?
-Yes true).
-Do you respect my parents?
-Yes (Tydyzh current!)
And in this vein another 17 (!!!!) times the girl shied on this question. The guys had a reason to talk about their relationship, and I had a firm belief that the device was not randomizing. Such coincidences simply could not be.
Deciding to figure this out, I went online and got a screwdriver.
To begin with, a couple of dozens of pages with information on the principles of operation of "adult" polygraphs were studied. As a result, it was found out that polygraphs monitor several indicators of a person: respiration, cardiovascular activity, electrical resistance of the skin (according to wikipedia).
To begin with, to understand which of these (or which of these) parameters my pocket polygraph might take into account, I took it apart. See photo below:
In the photo: 1 - reset button, 2 - initial calibration button and analysis start button, 3 - truth scale, 4 - contacts, 5 - strap.
Inside, I found 1 chip and speaker, which was responsible for the ominous sounds made by my polygraph. I made a logical conclusion and suggested that the chip is responsible for determining the untruth. By the number (M2080A1) I found this scheme in pdf format - you can download thatt. Completely forgetting the circuitry that I had been so carefully taught for 6 years at MEPhI, I scored on the circuit and began to think logically. Glancing at how, where, where, and which wires go, I concluded that this device is by no means capable of measuring cardiovascular activity and respiration. There would be more wires, and the circuit would be more complicated. To test my hypothesis, I armed myself with a heart rate monitor and began to check on the detector and watch the dependence of the scale on the pulse.
In normal condition, my pulse was 88 meters While I was answering standard questions like “What's your name, where do you live?”, The pulse remained almost unchanged, and the device persistently showed “unity” on the scale of truth. Then I began to increase the pulse (squat there, breathe quickly). On the pulse in 98-105, the device began to show a "deuce" on a scale. On the pulse of 120, he showed the "three", but did not want to beat me stubbornly. The changes in my “cardiovascular activity” were very strong, but the detector almost did not respond to them. At least not to the extent that it should. Therefore, my hypothesis was confirmed.
The only option left is the electrical resistance of the skin.
Electrical resistance is a scalar physical quantity characterizing the properties of a conductor and 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 operation of the polygraph on the resistance is as follows: a constant small current (not sensitive at all) is passed through the object (body), so that you can understand and fix when the resistance of the conductor changes.
And according to one hypothesis, when a person is lying, physiological processes occur in his body that affect the conductivity of his body.
Judging by the circuit and the wiring, this kind 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 percent sure that he determines the lie precisely by this indicator. If anyone has any suggestions, I will be glad to listen and test!
P.S. All testes had the impression that there was a certain dependence on the degree of moisture in the hands.
P.P.S. In general, he really defines a lie well, provided that the necessary conditions for the study on the polygraph are met - in silence, without distractions. In general, seriously. After all, if all this happens in a humorous manner, and a person has a fairly strong nervous system and healthy indifference, it’s hard enough to “burn” him, unless the question really forces him to tighten his buttocks!
After identifying people at the office who were shocked by questions like “are you cheating on your wife?”, “Are you cheating on your bosses?”, “Are you dreaming about sex with men?” etc., the gadget went to all the friends and parties I visited.
I want to say that people shied in different ways: someone rained already on the first question, and one girl (a really truthful dandelion) held out 23 questions without blows, but grabbed the question: "Do you steal money from your parents?"
All the inspectors had reasonable doubts - and is it not by chance that the device spoils the current and accuses it of lying? In principle, it was rather difficult to find this out in an empirical way: someone admitted that he had been hit in the case, while someone complained that he was shy about the “truth”.
One day a couple of friends came to visit me. Not in the sense that there were two of them, but in the sense that they were a couple m + f. This visit ended with a rather powerful scandal, and all thanks to this lie detector. It all started, as usual fun:
- Are you cheating on me?
-Not! (true).
Do you love me?
-Yes true).
.......
-Do you respect my parents?
-Yes! (Surge!).
Giggled and decided to check again:
-Your name is that?
-Yes true).
-You are so many years old?
-Yes true).
-Do you respect my parents?
-Yes (Tydyzh current!)
And in this vein another 17 (!!!!) times the girl shied on this question. The guys had a reason to talk about their relationship, and I had a firm belief that the device was not randomizing. Such coincidences simply could not be.
Deciding to figure this out, I went online and got a screwdriver.
To begin with, a couple of dozens of pages with information on the principles of operation of "adult" polygraphs were studied. As a result, it was found out that polygraphs monitor several indicators of a person: respiration, cardiovascular activity, electrical resistance of the skin (according to wikipedia).
To begin with, to understand which of these (or which of these) parameters my pocket polygraph might take into account, I took it apart. See photo below:
In the photo: 1 - reset button, 2 - initial calibration button and analysis start button, 3 - truth scale, 4 - contacts, 5 - strap.
Inside, I found 1 chip and speaker, which was responsible for the ominous sounds made by my polygraph. I made a logical conclusion and suggested that the chip is responsible for determining the untruth. By the number (M2080A1) I found this scheme in pdf format - you can download thatt. Completely forgetting the circuitry that I had been so carefully taught for 6 years at MEPhI, I scored on the circuit and began to think logically. Glancing at how, where, where, and which wires go, I concluded that this device is by no means capable of measuring cardiovascular activity and respiration. There would be more wires, and the circuit would be more complicated. To test my hypothesis, I armed myself with a heart rate monitor and began to check on the detector and watch the dependence of the scale on the pulse.
In normal condition, my pulse was 88 meters While I was answering standard questions like “What's your name, where do you live?”, The pulse remained almost unchanged, and the device persistently showed “unity” on the scale of truth. Then I began to increase the pulse (squat there, breathe quickly). On the pulse in 98-105, the device began to show a "deuce" on a scale. On the pulse of 120, he showed the "three", but did not want to beat me stubbornly. The changes in my “cardiovascular activity” were very strong, but the detector almost did not respond to them. At least not to the extent that it should. Therefore, my hypothesis was confirmed.
The only option left is the electrical resistance of the skin.
Electrical resistance is a scalar physical quantity characterizing the properties of a conductor and 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 operation of the polygraph on the resistance is as follows: a constant small current (not sensitive at all) is passed through the object (body), so that you can understand and fix when the resistance of the conductor changes.
And according to one hypothesis, when a person is lying, physiological processes occur in his body that affect the conductivity of his body.
Judging by the circuit and the wiring, this kind 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 percent sure that he determines the lie precisely by this indicator. If anyone has any suggestions, I will be glad to listen and test!
P.S. All testes had the impression that there was a certain dependence on the degree of moisture in the hands.
P.P.S. In general, he really defines a lie well, provided that the necessary conditions for the study on the polygraph are met - in silence, without distractions. In general, seriously. After all, if all this happens in a humorous manner, and a person has a fairly strong nervous system and healthy indifference, it’s hard enough to “burn” him, unless the question really forces him to tighten his buttocks!
