{"id":1878,"date":"2013-04-30T16:38:24","date_gmt":"2013-04-30T21:38:24","guid":{"rendered":"http:\/\/www.hephaestusproject.com\/blog\/?p=1878"},"modified":"2013-04-30T16:49:51","modified_gmt":"2013-04-30T21:49:51","slug":"creating-a-brain-computer-interface-headband-using-s-q-u-i-d-s-not","status":"publish","type":"post","link":"https:\/\/www.hephaestusproject.com\/blog\/2013\/04\/30\/creating-a-brain-computer-interface-headband-using-s-q-u-i-d-s-not\/","title":{"rendered":"Creating a Brain Computer Interface Headband Using S.Q.U.I.D.’s … NOT!"},"content":{"rendered":"

A\u00a0SQUID’s (superconducting quantum interference device)<\/a>\u00a0\u00a0is an electronic system that uses a superconducting ring in which one or two small insulating layers have been inserted. This device based on the\u00a0Josephson effect<\/a>\u00a0in the superconductor-insulator-superconductor sandwich. The\u00a0flux quantization<\/a>\u00a0in the ring makes it\u00a0extremely\u00a0sensitive to any magnetic field. Squids are so sensitive they can measure the magnetic activity of the brain in real time.\u00a0The majority of squids rely on conventional superconductors that operate at liquid\u00a0helium\u00a0<\/a>temperatures, -452.2 degrees Fahrenheit.<\/p>\n

\"SQUID\"<\/a>Fairly recently devices using the cuprate high temperature superconductors<\/a> have come to market.\u00a0With the creation of cuprate based SQUIDs<\/a>\u00a0the cooling requirements have been greatly decreased.<\/p>\n

\"BCI_or_Fridge\"<\/a><\/p>\n

Using a SQUID as the sensors for a Brain Computer Interface (BCI) is not a new idea. The first time I saw this concept was in the\u00a01983 movie Brainstorm,<\/a>\u00a0with\u00a0Christopher Walken and Natalie Wood.\u00a0The original unit they were using was a device the size of a\u00a0refrigerator that you placed your head into. Its large size was due to the\u00a0superconductors need to be cooled by liquid helium.\u00a0Then a cinema\u00a0plot device<\/a>\u00a0came into play, a superconducting chip\u00a0that worked at room temperature, reducing the entire device to a consumer friendly, lightweight headband.<\/p>\n

Todays exercise, creating a consumer friendly, light weight, SQUID based Brain computer Interface. Simple really …. if you look at it from an really odd angle. So it’s time to KISS <\/a>KIM and do an engineering hack job on this puppy.<\/p>\n

What do we need most to build a small lightweight BCI?<\/p>\n

Small lightweight self\u00a0refrigerating\u00a0SQUID’s are the answer. I bet you knew that already.<\/p>\n

The SQUIDs themselves are not the problem, they are manufactured using Integrated Circuit Fabrication technology<\/a>,\u00a0they a tiny little devices, just a couple micros across. Angels dancing on the head of a pin tiny, there are\u00a025,400 microns in one inch. Lets ignore the SQUID for the time being, and concentrate on how to reduce the size of the refrigeration<\/a>,\u00a0associated insulation, and shrink it down so we can pack 20-30 of them in a headband.<\/p>\n

To cool the SQUIDS there are four types of heat pumps<\/a> to choose from,\u00a0Compressor<\/a>, Magnetic<\/a>, Thermoacoustic<\/a>, and Thermoelectric<\/a>. Using a compressor is out, the weight, the voltage fluctuations, and the vibration all say poor design choice. Magnetic cooling is out \u00a0the SQUID is trying to detect minute magnetic fields and this cooling method will interfere. \u00a0Thermoacoustic<\/a>, yeah right … no, on two counts, who wants a 20 – 40 piezo crystals\u00a0vibrating on their head at high frequency all day, plus piezo crystals also give off minute EM pulses, making them unsuitable. That leaves only the thermoelectric heat pump.<\/p>\n

Thermoelectric cooling\u00a0uses the\u00a0Peltier effect<\/a>\u00a0to create a heat\u00a0flux between the junction of two different types of materials. Simply put you run DC current through it, and it pumps heat from one place to the other. The lowest temperature thermoelectric heat pumps work at is 100 degrees Kelvin<\/a>. Which is wonderful because high temperature superconductors will work at\u00a0temperatures\u00a0up to 133 degree Kelvin<\/a>.<\/p>\n

<This was\u00a0embarrassing, so it was removed><\/p>\n

\"sixstage\"<\/a>

six stage thermoelectric cooling module<\/p><\/div>\n

After doing all the math I come up with a 10\u00a0stage thermoelectric cooling module, made from 4 distinct material types for the thermoelectric heat pumps,\u00a0 two inches deep and using 20+ watts each to cool down to 115 K, with water cooling for outermost layer of the heat pump. \u00a0Which makes this an unworkable solution.<\/p>\n

What a waste of half a day. While I have come up with a working concept, it is not a viable headband BCI unless you have a neck the diameter of a telephone pole and wouldn’t mind wearing a 15 or 20 pound hat all day.<\/p>\n

Normally when I get an idea like this it has a workable solution. The only solution I see is higher temperature superconductors. Maybe I need a hollywood plot device…<\/p>\n

I should contact Joe Eck over at superconductors.org and see if he actually has come up with\u00a0room temperature super conductors<\/a>\u00a0running at 35 degree C …..yeah right, I will put that on the list right after, “contact the pyramid power guy and order a hat” ….<\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

A\u00a0SQUID’s (superconducting quantum interference device)\u00a0\u00a0is an electronic system that uses a superconducting ring in which one or two small insulating layers have been inserted. This device based on the\u00a0Josephson effect\u00a0in the superconductor-insulator-superconductor sandwich. The\u00a0flux quantization\u00a0in the ring makes it\u00a0extremely\u00a0sensitive to any magnetic field. Squids are so sensitive they can measure the magnetic activity of the […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[40,79],"tags":[],"class_list":["post-1878","post","type-post","status-publish","format-standard","hentry","category-bci","category-brain-computer-interface"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p29Kla-ui","_links":{"self":[{"href":"https:\/\/www.hephaestusproject.com\/blog\/wp-json\/wp\/v2\/posts\/1878","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.hephaestusproject.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.hephaestusproject.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.hephaestusproject.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.hephaestusproject.com\/blog\/wp-json\/wp\/v2\/comments?post=1878"}],"version-history":[{"count":23,"href":"https:\/\/www.hephaestusproject.com\/blog\/wp-json\/wp\/v2\/posts\/1878\/revisions"}],"predecessor-version":[{"id":1905,"href":"https:\/\/www.hephaestusproject.com\/blog\/wp-json\/wp\/v2\/posts\/1878\/revisions\/1905"}],"wp:attachment":[{"href":"https:\/\/www.hephaestusproject.com\/blog\/wp-json\/wp\/v2\/media?parent=1878"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.hephaestusproject.com\/blog\/wp-json\/wp\/v2\/categories?post=1878"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.hephaestusproject.com\/blog\/wp-json\/wp\/v2\/tags?post=1878"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}