LEGO lie detector makes interrogations fun

There are plenty of those gimmicky vocal stress level lie detectors out there, but as Robert De Niro made perfectly clear in Meet the Parents, nothing rattles the subject and amuses the proctor more than actually hooking someone up to the ol' poly. Unfortunately for amateur interrogators, CIA-quality lie detection equipment is expensive and hard-to-find, so LEGO-enthusiast Michael Gasperi's Mindstorms-based "Galvanic Skin Response Sensor" may be just the DIY option you need to liven up your next party. Basically a set of foil-lined velcro strips attached by 9V wire to an RCX control brick, Gasperi's lie detector works on the principal that people sweat more when they're fibbing, so his device measures the skin's electrical resistance of whomever's getting grilled. One word of caution if you decide to build one of these on your own: unless you want to end up under the hot lights of a real interrogation room, make sure to, like, keep your subject alive by powering your detector from batteries and not deadly AC.

[Via Make]

[Geraldine @ Mar 24th 2006 8:05AM]

Wow! now I can finally do my Scientology Auditing on the cheap!

[dreampc @ Mar 24th 2006 8:10AM]

Parents suckered into wearing this for their kids can now worry whether they will be asked those SPECIAL questions about where babies come from, Santa Claus, and the Easter Bunny.

[Dustin Tarditi @ Mar 24th 2006 8:25AM]

DreamPC, it works both ways - now parents can see if the "dog knocked over the lamp" or if someone was playing ball in the house...

[Tim Lord @ Mar 24th 2006 10:18AM]

Don't think "lie detector" -- think "E-Meter." :)

But if you can't help thinking :"lie detector" at least also think about "The Lie Behind the Lie Detector."

[james @ Mar 24th 2006 11:13AM]

Skin conductivity (i.e., resistance across surface of the skin) varies with many things: fear, anxiety, excitement as well as deception. This rudimentary device is an approximation of the more sophisticated Galvanic Skin Response (GSR) Meter.

A polygraph works by testing heartrate (via blood pressure), breathing rate, and GSR - the responses to various questions (standard ones: "Is today Friday?") is compared to the responses to relevant questions ("Did you kill Mother Mary?") and so on. It's notoriously inaccurate as a device for measuring "deception" - all spies are trained how to defeat it (to wit, it's never caught a spy - Aldrich Ames, the most notorious CIA mole passed two of them), but it is of some utility in exacting confessions from those ignorant of its limitations.

[Matt @ Mar 24th 2006 11:26AM]

I love that the first post is a rip on Scientology. Remember kiddies, nothing says great religion like having to essentially pass a lie detector test when asked questions about your faith. And nothing says indoctrination when the Clams are able to pass lie detector tests even when that faith ends up involving a belief in a 75 million year old galactic warlord named Xenu who has caused alien spirits to infest your body.

www.xenu.net

[John Smith @ Mar 24th 2006 11:44AM]

Isn't that what Tom Cruise uses to clear himself of Thetans??? Xenu Xenu

[lowbot @ Mar 24th 2006 11:47AM]

Yes Matt, thank heavens we've come to our senses and worship a carpenter who lived 2,000 years ago.

[Chris @ Mar 24th 2006 12:16PM]

Yay! Fighting about religion! Can we get back to talking about nice secular gadgets?

Oh and "...keep your subject alive by powering your detector from batteries and not deadly AC."

Um, this is just wrong. Coming down the tiny wire to the RCX is not 120VAC at 15A or anything silly like that. It's 9VDC at some low amperage where you may feel a slight tingle. Even then, why would plugging it in to the transformer instantly pass all the current through to the person?

[mgc @ Mar 24th 2006 1:04PM]

well that thing is cool. i'm unemployed, if anyone knows if the moon or ocean is hiring, pls keep me in mind.

oh, and check out a bunch of awesome photos:
www.salvosalvosalvo.com

[apt @ Mar 24th 2006 4:12PM]

#1: Just don't use AA batteries

[Andrew Logan @ Mar 24th 2006 5:06PM]

I agree with chris, I don't know much about electricity but I was under the impression that an AC adapter (which I'm guessing is required for LEGO mindstorms) regulates the voltage to be equal to that of the battery. I have blown out a couple devices by plugging in the wrong AC adapter, so at least make sure you use it with the one that came with your lego mindstorms kit...

[CRH @ Mar 24th 2006 7:10PM]

I remember doing this with an Atari 800XL and a hacked up paddle controller back in '86. Put it together from an article in Antic magazine. http://www.atarimagazines.com/v4n11/LieDetector.html Didn't work for nothing, but I convinced my brother and sister it did by asking them questions I knew they would lie about, then shorting the leads to make the onscreen graph go crazy! Fun.

[Morsicle @ Mar 24th 2006 7:37PM]

Careful, this device is not an official Scientology approved auditing instrument. Unless you use a $4,000 E-Meter you could end up a freak who believes in auditing away dead space alien ghosts to obtain an enlightened state of freedom from all bodily limitations and thus defeat the evil Lord Xenu�s designs � oh wait .. never mind.

[scientologyhater @ Apr 2nd 2006 8:16AM]

ANYONE who follows a hack science fiction author who clearly states his intention to get into a "money money money" making religion (LOL) that OBVIOUSLY involves science fiction as it's core belief introduction to being is not only misguided and lost, but severely lacking in ability for individuality, ability to think for one's self and use rational thought. Deprogramming instructions not included on that package, sorry. (oh, but John T. and Tom C. say it's true, so lets flock along) Sheeple. Anyway, cool looking device though.

[billy @ Feb 12th 2008 7:54PM]

You can take an online lie detector here

http://www.injurylawyers4u.tv/lie-detector/

[JJacobson @ Feb 19th 2008 1:45PM]

I could not get the Lego lie detector to work. Is there some trick I am missing?