Lie detector is an instrument uses to detect blood pressure, respiration and pulse. This instrument usually uses as a forensic instrument. It is commonly used in police station for investigation but this simple instrument can be use in your house.
This article tries to give you information to make a simple lie detector. Lie detector is also known as Polygraph. This simple detector can be extremely helpful if you want someone to tell you the truth. This simple instrument may be not as high-tech as the expert use but it could help you. This instrument operates by assessing the resistance of the skin that will down when you lie. Your skin will go down when you lie because lying will make you feel uncomfortable and nervouse. This reaction will make your skin go down.
The first thing to do before making the detector is preparing all the details. Here is the list:
1. MISC 1 Case, Wire, Electrodes (you can use electrodes with alligator clip but you can also uses wire or strap like in hospital), the simple one is wires and tape.
2. 4.5V batteries (2)
3. electrolytic Capacitor C1 1uF 16V
4. R3 1 1.5K 1/4 W Resistor
5. Q1 1 2N3565 NPN Transistor
6. Analog meter M1 1 0-1 mA
7. R2 1 5K Pot
8. R1 33K 1/4W Resistor
These components can be easily found in electrical shops. You can read on the components part to make sure that you have buy the right things. Then you can put and attach each component with the wire. Connect the batteries separately using wires. Put the analog meter between the batteries, so there will be battery wires battery using the wires between the batteries you put the R3 and analog meter. Then, the R1 and R2 after the analog meter is put there. Q1 is near the electrodes.
You need to adjust the analog meter to 0. Attach the wire using tape to the back of the subject's hand. If the analog meter changes from 0 it means that the subject is lying to you.