The Truth Meter: Don’t Sweat It

The Truth Meter: Don’t Sweat It
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When you feel nervous, excited, surprised, or otherwise aroused, you experience galvanic skin response (GSR). Your sweat glands, in responses to adrenaline and other hormones, start to release micro pulses of sweat. GSR is one component of polygraph tests because it’s an indicator of how nervous a question makes you feel. The increase in sweat causes an uptick in the electrical conductivity of your skin. The Truth Meter, a project from MAKE Volume 26 and Make: Projects is a simple circuit that you can make yourself that will indicate sudden changes in your GSR. So if you’re sleuthing to find out who left the empty milk carton in the refrigerator and your prime suspect does nothing but deny accusations, pull out MAKE Volume 26 and create your own Truth Meter.

Subscribe to the MAKE Podcast in iTunes, download the m4v video directly, or watch it on YouTube and Vimeo.

Download a PDF of the Truth Meter project from MAKE Volume 26 or check it out on Make: Projects.

In the Maker Shed:

Galvanic Skin Response Kit

2 thoughts on “The Truth Meter: Don’t Sweat It

  1. gyro2222 says:

    The most popular GSR device was designed in 1976. More than 1/3 of a million GSR2 in use today! The small, hand-held and self contained GSR 2 is a Galvanic Skin Response monitoring device for home biofeedback. The term biofeedback defines a method for teaching a person how to change a certain behavior or pattern, like breathing or tension in muscles, by providing some type of feedback on progress. For example, one way to learn to relax is to focus on your breathing. Repeated longer, slower breathing, will eventually lead to relaxed muscles. But how do you know you’re relaxed, or getting better at getting relaxed? That’s where the GSR 2 comes in. As your body goes through changes from tension to relaxation, many measurable biological things happen. Some examples are noticeable changes in muscle tension, heart, pulse rate and skin temperature. The GSR2 precisely monitors your stress levels by translating tiny tension-related changes in skin pores into a rising or falling tone. By resting two fingers on the sensing plates you learn to lower the pitch and your stress level. You basically get “biological” feedback through the GSR2 as you learn to relax and as you get better at doing it, you’ll find yourself relaxing faster with or without the GSR2. Most people use the GSR2 to relax, but it actually can be used as an assistive tool in other way’s as well. I use to help with meditation and visualization practice. I find it easier to get into a deep meditative state. Once I’m there I visualize my goals and plans and can better act on them. The Basic GSR2 includes biofeedback unit, earphone, instructional CD (side 1: “How to get the most from your GSR2”, side 2: “fully-narrated relaxation exercise”), 9V battery and operator’s manual. Search for it on Amazon.

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Matt Richardson is a San Francisco-based creative technologist and Contributing Editor at MAKE. He’s the co-author of Getting Started with Raspberry Pi and the author of Getting Started with BeagleBone.

View more articles by Matt Richardson


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