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Digital cootie detector

Kids love games of exclusion. This usually manifests itself in games of ‘keep away,’ having someone ‘catch cooties,’ or the ever-popular ‘No Brian club.’ [Rob] wrote in to tell us about the digital cootie detector he built. The cootie detector operates on galvanic skin response. It’s actually very similar to an E-Meter, although instead of Thetans this device measures something that actually exists.

Galvanic skin response is a measure of the skin’s conductivity. Skin conductivity changes because sweat glands will be activated when someone is nervous. This is a measure of psychological arousal, making it a great detector for games of exclusion – a kid who doesn’t want cooties will ‘psych themself out’ and give themselves cooties.

The build is based around an ATtiny45 with just a few resistors and paperclips required for a complete build. The ‘Cootie Detection Algorithm’ starts off with a flashing light – a great way to make someone nervous. After the test is completed, a green light means they can enter the quarantined area, while a red light means they must be excluded. There’s also a “device tampered” result – alternating red and green lights – that will show up when a clever child tries to short the paperclip leads. Check out the demo below:


  1. Decius says:

    Never heard of a ‘No Brian Club’.

  2. xorpunk says:

    @Decius: it’s a protected secret from people with cooties like you..

  3. Really? No one has ever heard of the No Brian Club?

    There was one everywhere I’ve ever lived.

  4. charliex says:

    scientologists and cancer cure all’s will soon be using this one too.

  5. Static says:

    Funny… I heard it was a different name… eeriely similar to my name.

    Couldn’t be related, could it?

  6. adam says:

    “something that actually exist” ROFL!!!

  7. Decius says:

    @xorpunk “Spend at least 3 million USD developing and publishing an AAA game, and then watch it get distributed on the internet for free by at least 10k users, *THEN* enlighten us with your economical wizdom..”


  8. Hirudinea says:

    This device will make impressionable people feel very sad and self-consenious, leading them to do stupid things and could even end up ruining their lives, its disgusting! Ok, enough about the E-Meter, that Cootie Detector is neat!

  9. rob says:

    Whoah! Are you telling me that my 3 year old may be a “Brian”, have cooties, be a decroded zombie, have cancer and/or be a Scientologist? I thought she just had sweaty hands because she’s a spaz! I’m dismantling this diabolical device. The world isn’t ready.

  10. Andrew Smith says:

    Hasn’t what happened in Norway taught us to be more understanding of others beliefs than less?

  11. rob says:

    I’m going to repurpose it into a sarcasm detector. Please hold your finger in the top right corner of your monitor for five seconds after you post. I’ll be here all night taking readings.

  12. ejonesss says:

    i thought a cootie was a medical condition that is associated with school aged boy/girl friend relations.

    “i dont want your cooties”

    “dont give me your cooties”

  13. @ rob: A sarcasm detector? That’s a real useful invention.

  14. N0LKK says:

    LOL; so this is to measure cooties, and it supposedly “measures something that actually exists”? Needs a bar graph or red yellow green LEDs. Claiming it measures, indicates something of a more adult nature would increase the sales potential. Make it coin operated, and place in bars to generate revenue.

  15. Will says:

    Aww, looks like we have a lifelong nerd on the post list. Reminds me of the song: Don’t play with Bruno. (Look it up on youtube).

  16. Charlie says:

    Ok.. so how do we build this? no parts list? no instructions? no code??? You guys are slipping…

  17. rob says:

    The basic build info is on the original YouTube video.

  18. Mike says:

    The only club I was ever in was the Pen 15 club.

  19. Hack Cell says:

    Hahah mike I’ll bet you were

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