How to make a portable handy lie detector in Altoid tin

Picture of How to make a portable handy lie detector in Altoid tin
Hi. I'm paewookyung, and this is my first posting in this site. please take note that
english is not my mother tongue. so please understand some of my gramatic mistake.;

Anyway, let's get this started!
This is a portable lie-detector built in Altiod tin. maybe you could have some fun useing this thing.

note: this detector is less sensitive then a real one. this could be miss some (many) of the lies.
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Step 1: Things you'll need.

Picture of Things you'll need.
You will need some things below for this project.

1. circuit board
2. 10K& resister
3. 47K& resister
4. 470& resister
5. 1M& resister x2
6. 47K& VR
7. knob for VR
8. 2N3904 transistor x3
9. 0.1 ? mylar cap
10. slide switch.
11. 9V bettery snap
12. LED (one red, one green)
13. solding tools.
14. drill
15. basic tools,
16. valcro
17. aluminum foil
....and most of all, Altoid tin!

Step 2: Make a finger pads

Picture of Make a finger pads
make a finger pads by sticking a aluminum foil to the valcro.
And don' forget to stick a wire between the valcro and thw foil!

Step 3: Solding the circuit

Picture of Solding the circuit
finished circuit 02.JPG
finished circuit.JPG
Solder the circuit as a diagram below. And before solding the circuit, cut the circuit board to

suitable size to fit in the Altoid tin

Step 4: Drilling the Altoid tin

Picture of Drilling the Altoid tin
Drill the Altoid tin for a VR.

and DO NOT use a sharp-end drill bit. it will tear the tin into half.

Step 5: Put the floor sheet

Picture of Put the floor sheet
Put the floor sheet in a floor of the tin to avoid circuit from 'shorting'.

and secure is with a glue.

in my case, I used a piece of box, and secure with a hotmelt.

Step 6: Put everything in order.

Picture of Put everything in order.
Put everything in a Altoid tin and secure all of them with a glue, hotmelt, E.T.C

Step 7: Done.

Picture of Done.
Now your lie detector is ready to go. first, put the finger pad to the finger of the 'suspect'
then, slowly, turn the VR until the 'true' LED is light, and the 'false' LED is dark.
then, ask a question to the suspect , when the false LED get light, the suspect is lying.
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dschoeman23 days ago

Anyone actually get this to work properly? Just getting the red light problem :/ any ideas?

venkateshh123 days ago

can you send me the back view of the finished circuit board?my email is venkateshharshit@gmail.com

sairak3 months ago

kindly tell me how can we make this project based on microcontroller???

epicTCK sairak1 month ago

That would be a waste of 20 bucks. Arduinos are cool, but alot of projects use arduinos when they are not needed. Unless you have to have one to make the project work, they tend to be a waste of money, and space.

tyscof epicTCK1 month ago

Pretty easy to find "Arduinos" for around 3 bucks

epicTCK tyscof1 month ago

where? in that case useful, but 21 dollars seems a bit much to me when you could usually make the project without.

noraiz.tahir2 months ago

you need to show two capacitors in the circuit diagram where we should attach the second capacitor and plzzz tell me what will be the value of that capacitor

sairak3 months ago

how can we make this project baised on microcontroller

sandhyaar4 months ago

HI.. this project looks quite simple.. But.. whats the assurance that it detects lie?? Can u please explain that perspective??

bwclark1014 months ago

I am sorry I mean, do you need the VR?

bwclark1014 months ago

Do you need to VR?

it's too much easy ... because i make it

hi bro...can u send me snap of ur project coz m crently working on this project???

KassidyGarvey6 months ago

I saw this back in October and wanted to do it for a school project so I went to radioshack and ace to try to find everything and ended up going to radioshack multiple times to get the parts. I built this with my dads help because i am new to circuits and we haven't been able to get it to work. the LEDs won't light up, we connected the LEDs to a wire and then to a 9 volt and they light up but then when we connected the 9 volt into the circuit nothing happened. can you maybe tell me what might have gone wrong? you can email me and i can send you pictures of what it looks like 18kagarvey@wausauschools.org thank you!

did you connected leds to 9volts with or without the limiting resistor?, if without then your leds are probably toasted.

yhdesai6 months ago


sowmya.ganti6 months ago

where do we attach that knob in the circuit..??

the circuit is not so clear..!!

manolis.kasos7 months ago

Can sb explain the working of the electronics of this and if anybody has tested this and if it works

can we use subsitute for Altoid tin

Fission Chips9 months ago

Awesome project! Thanks for putting this on the site.

did this work for you

plzz post the block diagram

Will a 50K VR work at all?


NazyaT1 year ago

you can snd pictures ya video of you circuit backside and frontside how u have wireing u have did i cant understand plz snd me pic ya vdo

bmann9999 NazyaT8 months ago

i cant understand what you just wrote there...

Can you add a video also ?

in circiut diamgram mylar cap is not their

NazyaT1 year ago

in circiut diamgram mylar cap is not their

in circiut diamgram mylar cap is not their

joelhacks11 months ago

is there a space between the aluminum foil, or does it touch?

NazyaT12 months ago

from where u have get how to make lei dector

NazyaT12 months ago

how to use it it continuesly red light burning

plz hel me

NazyaT12 months ago

plz reply me

my brother

NazyaT1 year ago

i cant see wiring proper le

NazyaT1 year ago

i have made this as same circuit digram i have on the switch on and it continusly red coming and green light is not coming what can i do plz hel me brother

about how much does this cost

0RUS01 year ago

I put it together like shown on the schematic, but all I get is a constant red light, and when I turn the pot all the way the green LED starts to glow, bu just a bit, and red is still on.
If anyone can please help

forever5671 year ago

I built this schematic but I can't quite get it to tell weather your telling a lie. When I turn it on it only lights up green. How can i fix this problem?

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