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jeffrey morris
08-17-2005, 06:17 PM
Is it possible for me to use BASIC Stamp 2 on Home Work Board to make a lie detector?

Jon Williams
08-17-2005, 07:53 PM
You *might* be able to use the Stamp's RCTIME function to create a simple GSR type lie detector -- but I think you're going to need a VERY small capacitor for the circuit. This link shows a connection the the Lego RCX; it may be a starting point: http://www.plazaearth.com/usr/gasperi/gsr.htm

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Jon Williams
Applications Engineer, Parallax

Jayguy5000
08-18-2005, 06:11 AM
depending on the age of the suspected liar, it doesn't need to be a working lie detector, just a mix of creativity with electronic objects could get the job done. Ive heard of a simple extension cord working http://forums.parallax.com/images/smilies/nono.gif

jeffrey morris
08-18-2005, 07:13 AM
Jon, I have the Lego Mindstorm and building sets but the company that makes it hasn't announced any new stuff for the Mindstorm set in a few years. I'm not sure about buying the Vex Robotics Kit at Radio Shack because I may not handle small parts well and I don't know if the kit is selling well or not. I have the lie detector that I built a few years ago but the battery terminal broke. I thought that there would be better lie detector. I always dream of the machine lighting the "True" sign when a person tells the truth and the machine flashing the "LIAR!" sign, yelling "LIAR!", and sounding the emergency siren when a person lies.

Paul Baker
08-18-2005, 11:04 PM
The skin resistance method is the simplest method (the one used in Jon's link). As the article states it is based on the amount of sweating the person does. But this is also the most unreliable method. A person sufficently nevous will create false positives and people who have control over thier body (pathological liar, experienced in meditation) will generate false negatives. Current systems use a combination of skin resistance and voice analysis, but the voice part is too complicated to do with a stamp. Since lie detectors are more of an art than a science (you need an expert to interpret the results to improve the accuracy) this may all be inconsequential to you.

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1+1=10

Chris Savage
08-19-2005, 12:00 AM
One other common test base besides skin resistance is heartbeat and breathing.

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Chris Savage
Parallax Tech Support
csavage@parallax.com (mailto:csavage@parallax.com)