Constructing my own lie detector.

[Paperchase]

I am in the process of making my own lie detector, not really for any good reason. It's just a fun little thing I could do when bored. Actually there is a use for it. I'm suspecting my little brother for stealing cigarettes from me, so I guess i'll bust him, if that's the case though.

Anyway. As for the schematic of the circuit it looks a little bit like this:

I've already checked the datasheets of the components, so I know what voltages, and how many Ohm resistors I need, and so on, so I know what components I need.

This is the list of components I need:

• R1 = 33k Ohm 1/4W Resistor
  
• R2 = 5K Ohm Resistor
  
• R3 = 1.5K Ohm 1/4W Resistor
  
• C1 = 1uF 16V Electrolytic capacitor
  
• Q1 = 2N3565 NPN (Negative Positive Negative) Transistor
  
• M1 = 0-1 mA Analog meter
  
• Misc = Wires, electrodes etc.
  

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​Question is: Do anyone know where I can get a hold of these components listed above? (Preferrably somewhere in Europe/ Northern Europe, but not a necessity).

[Bazingaman18]

Thats really cool and sorry I don't live in Europe so i cant help you with the parts.

[SpaceRaptor]

This is very cool indeed. I also can't help with the parts but be sure to keep us updated on how it's coming along! This is a very interesting thing to be making.

[Aphexx]

why do I have a funny feeling this is going to turn out like the time machine scene in Napoleon Dynamite

[Guest]

Just use eBay. I did a quick search on ebay.co.uk and found all the components that I searched for (5k .25, 33k resistor, the transistor) all either at electronics stores in the UK or from China with free shipping.

Here's one of the stores: http://stores.ebay.co.uk/Mallinson-E...p2047675.l2563

[Salmiakbal]

http://www.conrad.com/ce/en/FastSearch.html;jsessionid=644CFB28143673418CA3FBEC70C2B920.ASTPCEN28?search=resistor&initial=true&categorycode=

[bradscoolio]

Cool little project you have there :)

Will you be printing a pcb for it or using a bread board?

love the idea because there are so many under age smokers at my school and it's always funny when they get caught out xD

[Paperchase]

Cool little project you have there :) Will you be printing a pcb for it or using a bread board? love the idea because there are so many under age smokers at my school and it's always funny when they get caught out xD

I'm trying to keep the costs at a minimum, so I will be using a bread board, which I can hopefully borrow at my school.

[Paperchase]

http://www.conrad.com/ce/en/FastSearch.html;jsessionid=644CFB28143673418CA3FBEC70C2B920.ASTPCEN28?search=resistor&initial=true&categorycode=

Thanks. I will be doing more research into the website, to see if it's somewhere worth ordering from :)

[Baxterz]

Your sir..... are a genius!

[ErwinS]

Man I remember doing this as my science fair project when I saw it on a website in grade 6. Good times. Although it can be fooled quite easily.

[Paperchase]

Man I remember doing this as my science fair project when I saw it on a website in grade 6. Good times. Although it can be fooled quite easily.

Yes, of course this is not the most advanced of lie detectors currently known to man, but it will definately work on simple lies connected to "yes" or "no" answers.

You see, when you lie the electrical resistance in your skin goes down, which will be detected by the electrodes, which wil either result in diodes or an alarm making a sound. I haven't figured out which to use yet, but i'm probably just going to look at diodes as they are easier to set up in the circuit.

[Fordox]

+1 go to conrad.

lie detectors as this one are very in accurate though, it's use is more that your brother can not remain calm when questioned under the lie detector.

it's a lot of acting involved then that that thing actually works :P just make him break some sweat (and that is also how the machine works)

[Paperchase]

+1 go to conrad. lie detectors as this one are very in accurate though' date=' it's use is more that your brother can not remain calm when questioned under the lie detector. it's a lot of acting involved then that that thing actually works :P just make him break some sweat (and that is also how the machine works)[/quote']

I guess i'll try to get him a bit anxious before testing it on him, even though this is not my main purpose of constructing the lie detector. It is merely a fun little home project. :)

[Ghost]

Man I remember doing this as my science fair project when I saw it on a website in grade 6. Good times. Although it can be fooled quite easily.

Yes, of course this is not the most advanced of lie detectors currently known to man, but it will definately work on simple lies connected to "yes" or "no" answers.

You see, when you lie the electrical resistance in your skin goes down, which will be detected by the electrodes, which wil either result in diodes or an alarm making a sound. I haven't figured out which to use yet, but i'm probably just going to look at diodes as they are easier to set up in the circuit.

Doesn't seem like a fool proof method. :)

[symbianslave]

This is bit off your topic but may help you validate your gizmo..a few years back I took a workshop on hown to tell if the people I interview on job interviews is telling the truth, people who look up to the left are most likely telling the truth, it indicates that they are trying to recall from memory, and people who look up to right are making up things, just try it, try to remember something you want to remember while looking to the left and compare it while looking up to the right and see which is easier, or try it both again and this time, try to look at your side panel and think of a mod design, it should be easier if you look to the right..

hehe..just floating some thoughts here..