Mapping The Motor Cortex

May 14, 2012 by Caleb Kraft 24 Comments

[Bruce] sent us another fantastic final project from the ECE4760 class at Cornell. What you see above is an array of 36 near infra red LEDs shining into this young man’s brain for the purpose of spectroscopy. Light bounces back differently based on brain activity (blood flow). For this project, they are mapping their motor cortex and displaying it on a PC using a java app. You can see the entire rig, as well as the readings in the two videos after the break.

When this tip came in, one of our writers,[Jesse Congdon], chimed in as well.

hey I actually used to work in this as an intern, at Upenn. two frequencies of near infrared light are used that both penetrate skin and bone, one bounces off of blood in general and the other bounces off oxygenated blood. Since your brain actually regulates the flow of blood to parts that are in use you can see brain activity by looking at blood flow, but then you also need to see if the brain is actually using that blood, so oxygenation gives you a full picture. The frontal cortex is a nice place to measure cause there is no hair on that portion of the skull, and it gives you emotional responses and the “aha!” moment when you figure out a problem.

One article from way back said the system was going to be used as a lie detector, since when you lie you think about the truth and the lie simoltaneously and show an increase in activity.

It’s tough though to categorize a response since you can’t really establish “base line” activity by turning off the brain

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Hacking Magnets Into Your Skin

May 13, 2012 by Caleb Kraft 79 Comments

[Dave] loved his iPod nano so much that he implanted 4 magnets in his arm to hold it.

Ok, go ahead and shout “fanboy” at your screen and say something snide about apples products or lament the poor working conditions at foxconn. Got it out of your system? Cool.

Actually, if we had to guess, [Dave] really isn’t doing this all for his love of the device or the company. It is much more likely that he is just really into body modding and this was a convenient theme for a mod. We find the idea pretty interesting. We’ve seen implants before, but they are usually of the RFID type. Typically those are used for some kind of security or computer control.

Implanting a magnet, however, is interesting because it could almost give you a “sixth sense” You could detect what was magnetic, and how magnetic it was. If we were going to do something like this, we would probably go fully sub-dermal though to help avoid infection.

What other kind of implants could you realistically do with today’s technology to give yourself other senses?

Heathkit Closes Down, Again.

May 12, 2012 by Caleb Kraft 15 Comments

With this rather large flip flop, Heathkit has closed its doors… again. The company that so many of us remember fondly from their myriad of electronics kits originally closed its doors in 1992. Last year, there was an announcement of a revival and a call for kit submissions. Unfortunately, it looks like that just didn’t work out. While this isn’t an official announcement, the facts appear to line up to Heathkit closing their doors.

If you’d like to re-live a few fond memories, here’s a Heathkit unboxing at EMSL.

Destroying Stuff For The Good Of All Mankind

May 12, 2012 by Caleb Kraft 8 Comments

NC state’s constructed facilities laboratory is a place where things get broken for science. We’ve shared several videos lately of things being sliced, diced, sheared, exploded, and smashed, purely for the fun of it, and now we feel like we should compensate a little bit. No, we’re not going to undergo physical punishment, instead, we’ll share some educational destruction.

In the video after the break, you can see a few things pushed to their absolute limits, then a bit further. The Constructed Facilities Laboratory is a research lab that tests the limits of some of the infrastructure that we rely on daily. Bridges, roads, walls, support beams. Someone needs to figure out what they can really handle. Even more interesting than the short video below, are all the different videos in the tour that explain how the facility is constructed an how they operate. Take a few minutes and enjoy the tour.

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The Trials Of Working With Brushless DC Motors For The First Time.

May 12, 2012 by Caleb Kraft 9 Comments

We’ve all worked with DC motors at some point. Even if you aren’t a big hardware person, you’ve probably at least picked up a motor as a kid and touched a battery to the leads causing it to whir to life. These are usually standard DC motors and not their brushless relatives. Brushless motors require a bit more work since you are manually controlling things that are normally taken care of with the brushes. This article won’t teach you how, rather it will show you the mistakes one person made in his inaugural effort to use them. It is mildly amusing, but the project summary that he’s using them for seems even more interesting.

The job that’s been paying my bills and keeping me away from artsy-fartsy circuits for the past six months involves making a set of these enormous robot doors for a Certain Very Fancy Person’s house. Each door is 13 feet tall, around 7 feet wide, and weighs 1500 pounds. There are 66 of them in said house, and more in the servant quarters(!?!). The circuits on board each door have to handle running an onboard air compressor (which regulates a pneumatic weatherseal) as well as keeping track of temperature to linearize the pressure sensors when the weather gets cold. They also have to charge and maintain sealed lead acid batteries. They have commutated power rails. They have to communicate over said power rails, and do so using an capacitively-coupled data slicer and a proprietary protocol I wrote. This protocol has to be robust enough to bootload the processor over. It’s a proper embedded systems job.

Wow.

[via Adafruit]

The WiiKart, A Wireless Go Kart

May 11, 2012 by Caleb Kraft 15 Comments

Whoops… Looks like we covered this already. My mistake.

In case the name didn’t tip you off, this fun little kart was inspired by MarioKart. The goal was to build a functional go kart that could be controlled via the Nintendo Wiimote. They did a pretty good job and kept it fairly simple too. They designed a frame that vaguely mimics the shape of the carts in the game. The steering is handled by a 4″ stroke linear actuator. This was initially hooked directly to the tie-rod, but they found it to be too slow. Their solution was to put a lever in between the two with a 1to 3 ratio. This made everything much snappier.

Though they were capable of implementing PWM on the motors in their hardware, they opted to stick with full on, full off because of the push-button nature of the controller. The connection and communication are handled with an Arduino and they don’t mention what bluetooth module they use.

You can see in the video below it is fairly responsive and has more than enough power to lug a passenger over some varied terrain.

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[Matt’s] Bubble Display Updated

May 11, 2012 by Caleb Kraft 14 Comments

[Matt] emailed in to show us how he has improved his bubble display since the last time we saw it. If you recall from last time, he was having issues with the air pressure dropping when multiple bubbles were released, resulting in smaller bubbles. This time around, he has added an aesthetically pleasing air reservoir to help ensure that his bubbles don’t vary too much. There really wasn’t a reason to use two containers for the reservoir, aside from the fact it is what he had on hand. He has also torn part the part of the display that houses the oil, replacing it with individual tubes for each vertical segment. This makes it easier to regulate the speed of the bubbles, as he found they travel at a constant rate if they are in contact with the edges of the tube.

One downfall of using the vinyl tubes is the fact that it comes in a giant roll. This leaves the tube wanting to curl. To get around this, he stretched it on a wooden dowel and heated it with a heat gun till it relaxed. Using clear PVC or acrylic tubing would be an alternative but would be more expensive.

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