Sunday, April 24, 2011

The Las Vegas Anomaly

It seems all the iPhones as part of the once-unknown location tracking log all have visits to locations in northwest Las Vegas, all at the same time. Alasdair Allan and Pete Warden at O'Reilly Radar have dubbed this "The Las Vegas Anomaly", an elegant turn of phrase that will undoubtedly be incorporated into science fiction stories just as soon as writers get wind of it. Speaking as someone born and raised in Las Vegas, I have no clue why those locations are listed. There's not that much between the Kyle Canyon and Lee Canyon roads on US 95. A golf course, a small park, and scattered homes.

Sunday, April 17, 2011

Re: Magnetic Cable holders

Well, I had one issue with my magnetic cable holder: an incompatibility between the hot glue and the adhesive on a particular 'model' of holder. The ones with the adhesive and foam backing cleanly separated from the hot glue after a week or so under a slight load. I scraped the foam and adhesive off and reattached the magnet and the holder. I think part of the problem was difficulty in getting the hot glue thin enough before it set--this is a problem when attaching it to metal surfaces, which act as very efficient heatsinks. But other problem is the glue was not too gluey.

I've come across this incompatibility between hot glue and a few surfaces. The ubiquitous hot glue is EVA: Ethylene-Vinyl Acetate, a thermoplastic. I still need to make sure the adhering surfaces are hot glue compatible. It's really more about the convenience of the glue gun than anything else. I suppose I should be using a more universal glue for my generic adhesive requirements.

Sunday, March 27, 2011

Magnetic cable organizer/holder from hard drive magnets

I was talking with a coworker who had a particular design problem. Her network jack was embedded in a counter and the cable ran all the way across a built-in drawer to her desk and would frequently get jammed in the drawer. I suggested to her to talk to the Facilities guys to get some sort of cable management installed (as that's not my bailiwick) but I knew that the problem would persist into the future. I also thought there was little place to install anything that required a drilled hole, as there was AC conduit and such in the area. Then I had an inspiration: the network jack had been installed in a flat steel conduit. And I had a lot of hard drive magnets. So a little hot glue, some adhesive cable holders (that never really held very well), and I've got a solution! And now I'm making a bunch more for better cable management in my server room. I stuck a paper sticker on the magnet side to help prevent some of the surface marring these magnets can produce; a felt would probably be a better material.





Wednesday, March 16, 2011

Geiger Counter back up

My long-suffering Geiger counter is now back up and running.
http://www.lib.uchicago.edu/~dean/float.htm.

Now, as has been pointed out, this particular instance of this experiment is really an experiment, and is run only by me, for only experimental purposes. It doesn't represent any opinion or endorsement or opinion of any entity, whether the University of Chicago Library or the University or anything else. It is not a service. It represents nothing, is not calibrated, and should not be relied upon by anyone for anything. Don't email or call anyone but myself about it.

This instance is located in my office on the A-level of the Regenstein Library, the first basement level of a six-story building. The levels average about 8 microrads/hr here. Outside at Ryerson Physical Laboratory on the fifth floor, levels average to about 12 microrads/hr, which indicate the shielding provided by the Regenstein against the cosmic ray flux.

The problem I've been having with this counter was with the associated AW-SRAD software, which runs under DOS, doesn't appear to support virtual COM ports above COM4. On my Windows XP PC I had installed an Arduino which offered a similar USB Serial converter and I theorize at some point there was a conflict and the Geiger counter with its FTDI USB to serial converter took a high COM port at COM5. After removing the Arduino, I then disabled the real serial port at COM1 and forced via Device Manager->Ports->USB Serial Ports the port to go to COM1.

Tuesday, March 15, 2011

What's in the steam coming from a nuclear reactor

I've hesitated to comment much on the ongoing Japanese tragedy, but I wish to talk a little about the output coming out from the reactor whenever they open the valves to reduce the pressure inside. In commerical nuclear reactors not using heavy-water for their coolant (aka most non-Canadian western reactors) the pure water coolant is exposed to the intense neutron flux as it passes through the reactor. The neutrons can interact with the oxygen nuclei in the water to form nitrogen-16, a very short lived radioisotope with a half-life of seven seconds. After a few minutes away from the core there is none of it left so the only hazard is near the output pipe, and there are places they store the output for just a little while to let all of the N-16 to decay back into oxygen-16.
The other common isotope coming out is tritium coming from the small amount of deuterium in normal water, leaking through the fuel rod cladding, and other spalling type nuclear reactions in the materials in the core. The tritium is a low radioactive hazard but has a 12-year half-life.

If the reactor is hot, water will decompose into hydrogen and oxygen, especially with the right catalysts.

So if you were to open the output valve on a reactor to relive the steam pressure inside (because the regular cooling is not working), you would get quite a bit of that nitrogen-16. It would be gone by the time a few minutes of wind-time, but it is quite the hazard to the plant. I wonder how much of the periodic bursts of site limit radioactivity is related to that.

The introduction of seawater into the cores introduces the possibility of neutron activation of a number of other elements (sodium, chlorine, etc.) into radioactive isotopes that last longer and can have more of an issue in life time and clean up.

None of this discussion is about the breaking or melting of the cladding and detection of fission products (like what you see when checking people on their clothing for particles), which seems to have occurred in some fashion.

A good primer on what might be going on, without hysteria is over at MIT.

Thursday, March 10, 2011

Audio stereo isolation circuit diagram

Two years I made an audio stereo isolation transformer, suitable for getting rid of ground loop problems in a line-level audio connection. Here's a simple circuit diagram that attempts to match the colors of the physical device.




http://www2.lib.uchicago.edu/~dean/blog/isolation-transformer.dsn

Circuit diagram for TinyCAD.

Stereo audio isolation transformer in altoids tin

Monday, February 21, 2011

Adventures in Large Format Digital Photography: part 6: a new scanner camera

I am starting anew! After I got a bad back moving my box camera around, I've always wanted to reinvigorate the first generation scanner camera I made. It was built around a Agfa Ansco Viking Anastigmat f/6.3 lens from a medium format camera and a wooden mail inbox. The lens has incredible coverage. Here's a look with little modification to the sensor array plastic:

ScanImage015-contrast-sharp-flickr

When I used the lens on the first scanner camera with a highly modified sensor, it had coverage of about a 7 inch diameter circle.

The trick is not breaking the new scanner's firmware checking. As soon as I remove the pinhole lens array it started having issues. I had to add the pinhole lens back anytime a particular error message came back. I hesitated to modify the scanner because of the chance of permanent problem.

The new scanner (a Canon LiDE 90) was very sensitive to the position of the glass cover--it was very important to have the glass precisely in place to keep the initialization target in the right place.

Very, very carefully, I used a sharp x-acto knife to remove the plastic tabs and the two new rivets that go through the center of the CIS sensor board. I removed the LED light pipe by finding the tabs that hold it in.

Putting the sensor back immediately made it 'broke'. But I occasionally got it to work. In the end, it appears that unless there is illumination at the instant you hit the preview button in the TWAIN application, you will get the error 2,7,0. I'm still figuring this out.

large format flatbed scanner

Saturday, January 29, 2011

The neverending stupidity of astrology and Allstate

I won't get into the long-recognized shifting of the Sun's position and the calendar with regards to the zodiacal signs--as someone who has done a lot of astronomy astrology is one of those things that is like asking a chemist about alchemy--the rolling-eyes chemist can't believe the general public believes you can turn things into gold.

But Allstate, a statistical insurance companies with many many actuaries and other employees incredibly well-versed in mathematics, put out a press release (no longer available) claiming new Virgos were the worst drivers. The Chicago Tribune then put out a story on the press release. The new Ophiuchus was the best driver.

Now, for the shockingly bad details--whomever at Allstate failed to normalize the fact that the new signs have really different lengths--the Sun being in Virgo for a long time as it's a longer constellation (45 days) versus the short 6 day dip in Scorpio. Neither did the Tribune do its diligence in fact-checking this story, leaving it to an anonymous commenter to point out the utter stupidity of it.

I expected better from Allstate. You should have a few of the statisticians on your payroll take the PR people and their management for a little talk. You've lost the confidence of many customers who might know a little science or math, and it's embarrassing to have a company 1. Give a statement in a press release about astrology and 2. Completely get the numbers wrong. I also expected more from the Tribune press--unfortunately it appears companies can just put advertising up for free, caged as PR, and the newspaper will call it a story straight.

Tuesday, January 25, 2011

Making Things Talk & Processing projects

I got Making Things Talk as a gift from a great friend of mine and I just ran two of the projects in the "Identification" chapter.

To start off, you install Processing, a free language for visualization. For me the download for Windows was here. It's a slightly different install process than usual; just make a directory like "C:\Program Files\processing-1.2.1" and dump the contents there, and make a shortcut to processing.exe somewhere convenient for you (or you will forget it's installed).

Then in order to do video things you first need to have quicktime installed; if you have iTunes then you've got quicktime. And, finally, you need a VDIG implementation; for Windows it is WinVDIG. Install version 1.01 from here.

The first project was finding a particular color in a webcam image, reading the color, then putting a pointer on that spot.

Hey it works! See the dot on my nose?
The screenshot misses the dynamic aspect of the little dot following you around.



The second project was using your imager to decode QR Codes--and ha ha, check out the sample from the book. Nice one, Tom Igoe.


Great stuff.

P.S. I just loaded the 'slitscan' example from the Processing examples. Ha!

Monday, January 10, 2011

Two new trends to keep an eye on in 2011 and beyond: 3D printing and Mobile Security

3D printing and mobile security are two big trends to watch.

The next big thing will be 3D printing. It's a hobbyist field right now, with rudimentary designs and machines, but it's going to get better. What happens when you can replicate any physical thing? That part that broke on your dishwasher, your bike, or that toy--you will just make (or buy from some third-party) a replacement. You won't buy the part from the manufacturer (even if you could). Those cheap things that break and then you throw out? Why would you if it could be easily fixed for next to nothing from a machine you had under your desk?
The best approach to this emerging market is to keep it open, free from patents and IP, and let it flourish. Many organizations and business interests will attempt to get a stranglehold on the emerging field, and it's important not to let that happen, lest they stifle the innovation an open field offers. The Internet would absolutely not be what it was if large corporations controlled it.
Dan's Data has an interesting post about the future of 3D printing.

Mobile Security needs to be addressed. We sat with cellular phones in a controlled world with little to worry about, as the oligarchy of carriers strongly restricted what could be run on their phones and networks. That worked at the cost of innovation. The new world of open platforms on the smartphone now means maliciousness is around the corner if the native OS isn't correctly applying security features like sandboxing. We need phones; we use them all the time, all day, and we need to be able to summon people in emergencies. We can't let them break because of bad security. We need to be able to prevent mass Denial-Of-Service, worm outbreaks, malicious breaking of phone security, and surveillance on these devices. And it's not just having the carrier control the phone; mobile security is also about You having control and not letting Them (whether they are a cracker or a malicious app or the Carrier) reading your data.

(While mobile security needs to be addressed as an emerging issue, that in no way reduces the disaster of the current free-for-all in web plug-in security holes).

UPDATE: for instance this finding of SMS messages that can kill nearly any phone.

Sunday, December 26, 2010

Partial solar eclipse on January 4th

The eclipse season continues, as the Moon's nodes--the intersection line of the Moon's orbital plane and the Earth's orbital plane--continue to point in the direction of the Sun and anti-Sun. After the winter solstice lunar eclipse Europe, Northern Africa, and the Middle East will get a partial solar eclipse on January 4th. The maximum eclipse reaches nearly 86% in Scandinavia, although I wouldn't really trust a low-altitude solar eclipse at the Arctic Circle this time of year to be likely visible.

Since we know the Moon's orbital plane right now, we can extrapolate to the appearance of the Moon in upcoming months and phases. We know that the first and third quarter Moons will be either higher or lower away from the ecliptic, since at new the moon was obviously at the ecliptic (to produce the eclipse). So we need one other piece of information to give us the appearance of the Moon in the sky: is the node ascending or descending? Recall the Moon passing Jupiter about two weeks ago.
Was it above or below Jupiter in the sky?

Sadly, I had to check via a planetarium program because I couldn't remember. It passed above Jupiter. So the node is ascending, and the First Quarter Moon in January will be higher than usual in the sky and the Third Quarter Moon lower (but keep in mind only in deviation from the ecliptic, not in absolute elevation in the sky). In three months (aka March-April) the full Moon will be lower in the sky than usual and rise and set further south than normal.



http://eclipse.gsfc.nasa.gov/OH/OH2011.html

Wednesday, December 15, 2010

Light Pollution also boosts air pollution

In addition to causing breast cancer, light pollution has now been shown to affect the atmospheric chemistry at night in urban regions, increasing the next day air pollution by up to 5%. Ignoring any deleterious effect on astronomy, why are we being idiots on this? Why can't people aim lights correctly so they don't miss well over 50% of the thing they want to light? Why can't we understand if you want to light something on the ground, you can't do it by sending light up?

http://www.bbc.co.uk/news/science-environment-11990737

http://www.treehugger.com/files/2010/12/urban-light-pollution-boosts-air-pollution.php