A polygraph, commonly known as a lie detector, is a device used to measure and record several physiological indicators such as blood pressure, pulse, respiration, and skin conductivity while a person answers a series of questions. 

The basic parameter on the basis of which the reliability of the response is determined is the galvanic skin conductance. This device is actually a modern replica of the so-called E-Meter, device used in Scientology practices.

 Officially known as the "Electropsychometer," it was invented by Volney Mathison and later adapted by Ron Hubbard, the founder of Scientology. The price of an original device like this exceeds an incredible five thousand dollars. The device presented in this video is based on the Theremino Master board, it is very cheap and simple to make, and has identical or even better features and options than the original device. 

 Theremino is an Open Source system, to connect computer with the real world. Unlike similar systems (for example Arduino), this system works immediately, and does not require any firmware programming. The communication between the PC and the external components is done through "Theremino Master" board which is just an input-output device and not a micro programmable controller as Arduino.

 You can get theTheremino Master board ready for about twenty dollars or make it yourself, because the code and instructions for making it are free.   You now have more than 150 great Windows applications on the Theremino website that allow you to control the components, modules, or sensors connected to the Theremino Master board. The Thermino system uses the power of the PC and the flexibility and low cost of the microcontrollers, so with this combination we can make great device.

   The device is extremely simple to build, in fact, like all Theremino projects, and consists of only a few components:
   - Theremino Master board
   - Resistor 22K  (Red, Red, Orange, Golden)
   - Capacitor 1µF
   - and two electrodes actually two metal cylinders

 This project is sponsored by PCBway. This year PCBway is celebrating the 10th anniversary of its successful existence. On the occasion of this event, PCBway provided its users with more conveniences such as big savings for certain products, as well as discounts of up to 80%. From July 1st to July 31st, log in to the PCBway site, and start the PCBway 10th Anniversary Tour, where you will enjoy Coupons, Lucky Draw, Exclusive Badges, unboxing blind boxes, and many other surprises. PCBway is always your great choice.
    The software part consists of a beautiful Windows application developed by the Theremino team. The application is graphically designed to be very similar to the original device made with discrete components.

  However, this software completely automates the entire setup process, and also contains a number of useful additional options.
    Now, let's briefly explain how to install and run the software. First we need to download the app Theremino Emotion Meter c. 3.1 from the given address . Then we unpack the archive into a folder that contains all the necessary files. We activate the .exe file, which automatically starts the Theremino Hal application, in which the characteristics of the board's inputs and outputs are defined. In this case the Theremino Hal should look like this.

To check the functioning of the device, we should hold the electrodes with both hands, during which a deflection should appear on the scale. And now I will try to explain to you the way of working with the device as briefly as possible, and you can find a detailed description in pdf format on the website given above. he E-Meter measures changes in the electrical conductance of the skin, similar to the Galvanic Skin Response (GSR) used in polygraphs. The idea is that mental and emotional states can affect the body's electrical...