Your Brain Thinks Its Burning You, But It’s Not

Thermal Grill

In the cult classic Dune, there’s this fictional device called the “Pain Box”. If you touch it, you’ll feel like your hand is burning, but in reality, no tissue is being damaged. In the real world this is called the Thermal Grill Illusion, which was discovered back in 1896. Much to our chagrin, [Adam Davis] has just finished building a working prototype.

Sound familiar? We covered a similar project a few months ago — but unfortunately it didn’t work very well. Luckily, and boy do we love it when this happens, [Adam] saw the post, and got inspired to try it himself. He had actually designed a system years back but never got around to building it. Upon seeing the post — and the difficulties in making it work — he just had to figure it out.

So how does it work? The Thermal Grill Illusion uses alternating warm and cool bars which stimulate the temperature receptors in your skin — and confuse them. Neither the warm or cool bars are extreme enough in temperature to do any harm, but your confused little temperature receptors make it feel like you’re either burning or freezing your skin off!

To do this, [Adam] is using thermoelectric coolers (TEC’s) which use the Peltier effect to cause a temperature differential between two sides of the device. Some temperature PID controllers make sure everything stays in the safe temperature range — TEC’s can get super hot, or cold! The resulting system works well, and really shows off the effect nicely; just take a look at the following demonstration.

48 thoughts on “Your Brain Thinks Its Burning You, But It’s Not

    1. hes probibly needs to monitor the center sink to get a proper differential measurement. im not sure if this is neccisary for a production device, but is useful for science.

        1. Waterboarding is psychological as well … cheaper too.

          A couple of gallons of water and a few towls in each police car and your next traffic stop can get a whole lot more interesting.

        1. I’ve seen hot ones, and cold ones, but I’ve not seen a single one that does both temperatures at the same time. Mostly because of the pain threshold needed. But now that the idea is out there, be sure that one will be made (maybe I’ll make it, getting it certified would get a corner on a very small part of a large market).

          Then again, I haven’t been shopping in those districts of the internet lately. My favorite shop shut down and I haven’t needed anything new recently. If you, Lord Nothing, know of a place that has those, let us know; I need new stuff.

        1. Generally considered to take a bit of acid.

          I only know because I had a nail removed that grew back all strange, got removed again and scrubbed with phenol to keep it gone. Hospital grade phenol isn’t the weak 5.5 pH stuff.

    1. No. The Gom Jabbar was the little needle attached to a finger thimble that was filled with a deadly poison. It was designed to inject that poison directly into the jugular vein, delivering the poison to the brain in a heartbeat. It was held at the throat of those who were being tested by a Bene Gesserit to see if they were Human.
      The pain box in Dune lore was called a pain box and worked through “nerve induction”.

      1. Would be held to the carotid artery, not the jugular vein. Slice just one jugular and (contrary to soooo much medically incorrect TV and movies) the victim will have at least a couple of minutes. Cut a carotid artery (the right or left common which come directly off the aorta, or higher up the neck where they split into the interior and exterior) and pressure to the brain drops instantly, with consciousness quickly lost. The scenery would also get a good spray coat of blood. *looks at a diagram* The left common carotid would probably be “best” because it connects directly to the aorta. The right common has a short bit called the brachiocephalic artery between the aorta and where the right subclavian artery branches off. The left subclavian connects directly to the aorta. Odd bit of asymmetry there.

    2. i always thought the gom jabbar was the name of the bene geeserit test to see if someone is human and not an animal. but looking back at the book it seems like its also the name of the poison needle used in said test, but can apply to either.

  1. “I must not troll. Trolls are the mind-killer. Trolls are the little-death that brings total obliteration. I will face my trolls. I will permit them to pass over me and through me. And when they have gone past I will turn the inner eye to see its path. Where the troll has gone there will be nothing. Only I will remain.”

  2. A simple way to experience this effect is to tightly pinch a peltier between your thumb and forefinger. Shortly after turning it on you’ll reflexively drop it unless you actively try to hang on. I figured the effect was psychological, but I didn’t know it’s name until now.

  3. Now, try modulating (levels, or “polarity”) the temperature difference and see what it does to the effect. At 42Hz alternation, maybe your inner universe will explode.

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