brainwagon "There is much pleasure in useless knowledge." — Bertrand Russell

31Aug/110

Wireless Bluetooth RS232 TTL Transceiver Module – Free Shipping – DealExtreme

No commentary, I just found a reference to this module in this cool article on making a VGA scoreboard. The author intends to send information to an AVR using this module, and the price and capability seems pretty good.

Wireless Bluetooth RS232 TTL Transceiver Module - Free Shipping - DealExtreme.

Filed under: electronics No Comments
28Aug/115

Donald Michie, Alan Turing, Martin Gardner, and Tic Tac Toe

As anyone who reads my blog with any regularity will tell you, I like to read and learn new things. The problem with being self taught and also easily distracted means that you often learn a great deal, but don't always perceive the connections and scope of what you are learning. I found another example today while surfing.

Years ago, I remember reading one of Martin Gardner's Mathematical Games columns (from March, 1962, in case you want to look it up) where he described an interesting machine for playing tic-tac-toe. It was made entirely out of matchboxes, each one of which had a tic tac toe position on the top. Inside was a collection of colored beads. Each color specified a possible legal move for the position on top. The idea was that you'd play a game by drawing these beads from the appropriate box, and making the appropriate move. At the end of the game, you'd remove the bead from the last box that sent you along the losing path. Eventually, all the losing moves get removed, and the machine plays perfect tic-tac-toe. Gardner showed how this same idea could be used to create a matchbox computer to play hexapawn, a simple game played with six pawns on a 3x3 board.

I really haven't given it much thought since then. Many of you have probably read this article in one of the collections of Gardner's columns.

But today, I was surfing through links and reread some of the details. I found that the machine was called MENACE (Matchbox Educable Naughts and Crosses Engine) and was invented in 1960 by a gentleman named Donald Michie. And it turns out that he's a pretty interesting guy.

He was a colleague and friend of Alan Turing, and worked with him at Bletchley Park. Apparently Michie, Turing and Jack Good were all involved in the British code breaking efforts, and in the creation of Collosus, the first digital programmable computer which was used to crack the German "Tunny" teleprinter code. (Good and Michie were apparently two of the authors of the General Report on Tunny, a report on the cracking of the code which has only in recent years become declassified). None of this work could have been known by Martin Gardner at the time of this publication. Of course, this was also true of Turing's work as well.

Turing made a huge impact in several related disciplines: in mathematical logic and computation, in his wartime efforts in code breaking, and in his role in creating some of the first digital computers. Turing also became interested in mathematics in biology, writing about the chemical foundations of morphogenesis and predicting oscillatory chemical reactions. Michie received a doctorate in biology from Oxford, but returned to have a profound and lasting influence on artificial intelligence. Oh, and that modest little paper on Tic Tac Toe? One of the first instances of reinforcement learning.

Very cool, to discover that the little bit of reading you did as a teen, which seemed like an insignificant game at the time, actually has profound threads which stretch out into lots of different areas.

Donald Michie's Home Page
Trial and Error, the paper describing MENACE

26Aug/112

Don Henley on the PROTECT IP Act

Today I noticed an editorial by founding member of the Eagles, Don Henley asking for the passage of the PROTECT IP Act currently stalled in the U.S. Senate.

The basic of idea of the PROTECT IP act is that the Attorney General or private intellectual property rights holders can ask the court to issue an injunction against foreign "rogue" sites whose primary purpose is to engage in intellectual property violations. When such an injunction is granted, search engines, Internet providers, credit card companies, and ad networks would be required to cut off all access to these sites.

There are perhaps some arguments to be made for such an approach, but Henley doesn't seem to find them. Instead, he seemingly wants to engage in dramatic hyperbole. He begins with a claim that foreign websites trafficking in "American arts and entertainment products" cost the U.S. 58 billion dollars annually and 373,000 lost jobs, with 16 billion dollars in lost earnings and 2.6 billion dollars in lost tax revenue. Wow! That does seem serious.

But where do these numbers come from? Apparently from this study this study by IPI.org. These numbers are apparently drawn from a study which examined data from 2005. But where did they get these numbers? By numbers which are for the most part reported by industry groups that represent rights holders, rather than by any actual statistics on piracy costs. For instance, the IPI study highlights numbers from the Business Software Alliance, a group which has been widely criticized for methodology which exaggerates the cost of infringement on copyrighted software.

But we could argue about what those numbers are all day. I'm not going to really try to argue them because I doubt any meaningful numbers exist. I certainly have none that I would propose.

What is really disturbing is that it can't possibly work. The PROTECT IP Act requires that DNS servers and search engines remove the information and routes that would allow American citizens to reach these foreign infringing websites. In other words, it requires them to censor websites. And in the words of John Gilmore,

The Net interprets censorship as damage and routes around it.

If domestic name servers start to censor individual websites, all we will have done will be to create a market for offshore name servers and search engines which aren't censored. The Internet is supposed to allow every end point to talk to every other end point. That is what it is for.

This article lists eight different ways to circumvent the PROTECT IP Act. It's easy. Really easy. Provide incentive to anyone, and it will be even easier. It's not like every downloader needs to be smart. As Mike Godwin said, all you need is one smart cow, the rest will follow him out the open gate. It's not clear that the PROTECT IP Act will recover even a single dollar of lost revenue, or create one job.

Unless of course, you consider the government jobs it creates. The Congressional Budget Office estimates that enforcement of the law will cost about $10 million annually, and will require the Justice Department to hire 48 people. It should be noted that this does not include the cost to tech companies for whom compliance with the Act is simply an expense.

But what really irks me about Henley is this paragraph:

Critics of this pending legislation need to be honest about the company they keep and why they essentially aid and abet these criminal endeavors. The Electronic Frontier Foundation (EFF), a civil liberties group, claims such a bill would "break the Internet," while Google Executive Chairman Eric Schmidt says it sets "a disastrous precedent" for freedom of speech. No one has the freedom to commit or abet crimes on the Internet. Stopping crime on the Internet is not, as EFF says, "censorship." There is no First Amendment right to infringe intellectual property rights.

It begins with an intended slur: if you object to the PROTECT IP Act, you are aiding criminals, as if there were no reason to object to it. You could object to it on the grounds that the MPAA and the RIAA have consistently misrepresented their losses. That they have continued to successfully lobby for increasingly expansive and draconian remedies against infringers. That legislation like the PROTECT IP Act do signficant damage to fundamental principles like "presumption of innocence", "burden of proof" and "freedom of speech". And from my view, that it cannot possibly work without creating greater damage than it prevents.

Google CEO Eric Schmidt said it thusly:

"I would be very, very careful if I were a government about arbitrarily [implementing] simple solutions to complex problems," he said. "So, 'let's whack off the DNS'. Okay, that seems like an appealing solution but it sets a very bad precedent because now another country will say 'I don't like free speech so I'll whack off all those DNSs' – that country would be China.

"It doesn't seem right. I would be very, very careful about that stuff. If [the UK government] do it the wrong way it could have disastrous precedent setting in other areas."

In the United States, we are supposed to consider even bigger issues than money and jobs.

Don Henley: Internet theft is a job-killer, too - USATODAY.com.

25Aug/111

Mag 7 Star Atlas Project

Tom mentioned that a new supernova had been found in M101, a spiral galaxy in Ursa Major. While I used to be a bit of a telescope maker, and could generally find my way around the sky, I wasn't one hundred percent certain I knew where to find M101. So, I turned to my copy of
Uranometria 2000. And... I still didn't know really. The charts in that book are good for star hopping at the eye piece of a telescope, but less so for just finding your way around the sky.

In digging around for a decent online map, I found a link to the Mag 7 Star Atlas Project by Andrew L. Johnson. It's a very nice 21 page atlas, which is very pretty, and is excellent for both visual use, and use with small telescopes or binoculars. And it's licensed under the Creative Commons too! Win!

Below is a JPEG of the first chart, rendered at 2K wide. The actual atlas is in PDF format, so will print out at the full device resolution, and will look even nicer.

Here's the link:
Mag 7 Star Atlas Project : Andrew L. Johnson : Free Download & Streaming : Internet Archive.

Filed under: Astronomy 1 Comment
25Aug/112

Q: Should blogs make font choices for you, or not?

I've been making some minor tweeks to the excellent 1024 px WordPress theme that I started using a few weeks ago. I found a small issue with the CSS for images that are supposed to be center (a priority mistake meant it didn't work) and I've made a few other minor tweaks. I finally got around to considering some questions regarding fonts, and I thought I'd ask you, my readers, give me the benefit of your opinions.

The 1024px stylesheet listed Verdana, Tahoma, Arial, and sans-serif as the search order for fonts. Not a bad list really, I think Verdana is an excellent screen font, with excellent legibility and good weight. Since my eyes have become somewhat presbyopic, and I spend a great deal of time reading stuff on screen, I've become somewhat more sensitive to these kind of issues.

But there are a couple of problems with the defaults.

First of all, Verdana and Tahoma (which are truly excellent, it must be said) aren't really universal. I believe that they are installed by default on Windows and Mac OS, but not on most of the Linux installations that I have seen. On most Linux boxes, I end up using Dejavu Sans as a substitute.

If you don't have either Verdana or Tahoma, this theme falls back onto Arial. I do have Arial installed on most of my systems, because lots of things need Arial or Helvetica. But here's the thing: Arial is really ugly. It's not pretty even in print, but it's just wonky to use on screen. Sadly, this is what I get a lot of the time.

And, of course, if you don't have any of those three, it falls to the browser default sans-serif, whatever the system default is, or whatever you've chosen.

Okay. So, I thought that perhaps i should just leave it up to you. I've all the font selections from the theme's stylesheet. Whatever default you configure is what you get.

And yet, I'm not happy with that either. It appears (for instance) that on Mobile Safari, the default is always a serif font, and you can't change it. That's not very good: I think serif fonts are virtually by definition harder to read on screen. Mobile Safari does support Verdana. I could actually make a special style sheet just for my blog, but that seems to be a slippery slope.

So, the question is: do you think web page authors (and in particular, blog authors) should make font choices for you? If so, what choices are reasonable? If not, are there drawbacks?

Feel free to leave a comment below.

Addendum: Okay, I shifted back to specifying fonts. By default, mobile browsers like Safari on the iPad and iPhone seem to resort to a serif font, which on a tiny screen is simply not a good idea. The list I came up with was Verdana, Tahoma, DejaVu Sans, and then whatever "sans-serif" is. Arial is just too ugly to use.

24Aug/111

Some thoughts as Steve Jobs resigns as CEO of Apple…

Breaking news: Silicon Valley pioneer Steve Jobs has stepped down as CEO of Apple, and Tim Cook will be stepping up from his previous role as chief operating officer to become CEO.

This post talks a bit about my employer, Pixar Animation Studios, but in no way should be construed as anything but my own opinion. I cannot, and do not desire to speak for them.

Without doubt, TV, papers, blogs and everyone else will be spending time over the next few days looking both forward and back over his career and predicting what the future holds for Apple and Steve himself. I won't peer into my crystal ball for either: I have no special insight with regards to either, but in the twenty years I spent at Pixar, I did have a view from the side lines, so I thought I might offer a bit of perspective.

Anyone who has talked to me for any period of time knows that I'm not a typical fan boy. I have an inherent skepticism about the rich and powerful. We have a culture in the U.S. which tells us that the those who are successful must be different from the rest of humanity. They simply must be smarter, or braver, or more creative or more insightful than the rest of humanity. I don't believe it. The fact is that while all those factors play some role in success, good old fashioned luck also plays a role. You could be smart, diligently apply all the advice you got from all the smart people you know, and you won't necessarily become the next Mark Zuckerberg, Sergey Brin, Bill Gates or (yes) Steve Jobs. I suspect that there are alternative universes where Steve Jobs isn't even Steve Jobs: where a seemingly meaningless event occurred in his alternate existence, and Apple doesn't get formed. I'm also one of those lefty socialists who doesn't believe that there is necessarily a link between that which is good and that which is profitable.

But in spite of those caveats: I still think Steve is a remarkable leader. Perhaps uniquely so.

I've worked at Pixar since 1991, and in those early days Steve was seen regularly around our campus. I was just a beginning programmer back then, in my first real job, and I couldn't help but be intimidated (not a usual emotion for me). He was a force of nature. He was ruthless and uncompromising in his pursuit of his vision, and seemed to have little patience for those who didn't share it. But I've experienced the reality distortion field first hand, and it's very real.

Here's the thing: he really does have a vision. A bold vision. An inspired vision. And he has an amazing talent for surrounding himself with people who could help in achieve that vision.

The success of Apple and Pixar both required a bit of luck. You can look back to individual things that occurred, and had things worked out a bit differently, perhaps neither would have become the iconic brands that they both have become. But there is no doubt in my mind that Steve's leadership was essential to the success of both.

Pixar and Apple share a simple principle: that producing good products is the way to build a good company. For Pixar as a film studio, story matters. For Apple as a producer of computers and consumer products, design matters. Both companies try to produce stuff that is simply insanely great. There is a certain respect that both companies have for consumers. Both believe that it is important to put out good products. Customers can tell the difference. Your second best work is not sufficient. Only your best can change the world for the better.

And yes, before everyone piles on, there are lots of things that I don't particularly like about Apple, not the least of which is my aforementioned skepticism about anybody or anything which becomes too powerful or influential. I don't really want Apple (or Facebook, or Google) serving as mediator for all my interactions with my fellow man. My support of open source and the culture of sharing is in conflict with the universe that Apple and Steve himself would probably desire. But whatever philosophical differences I have with Apple, I'm reassured that Apple at least has a philosophy, and whatever failings it might have: it's forward looking, and centered around producing the kinds of products that people want to buy.

Tim Cook, you've got some big shoes to fill.

To Steve Jobs, thanks for challenging not just your companies but the entire computer industry to "think different". You're going out on top. Best wishes for health and long life.

Filed under: Rants and Raves 1 Comment
23Aug/110

How-To: Coffee Can Radar

This is awesome! MIT has created an interesting course as part of the their Open Course Ware project: it describes how radar can work, and as a final project, students were expected to build an test a simple radar system. Their description:

Are you interested in building and testing your own imaging radar system? MIT Lincoln Laboratory offers this 3-week course in the design, fabrication, and test of a laptop-based radar sensor capable of measuring Doppler, range, and forming synthetic aperture radar (SAR) images. You do not have to be a radar engineer but it helps if you are interested in any of the following; electronics, amateur radio, physics, or electromagnetics. It is recommended that you have some familiarity with MATLAB®. Teams of three students will receive a radar kit and will attend a total of 5 sessions spanning topics from the fundamentals of radar to SAR imaging.

I haven't read a lot of this, but I'm bookmarking it for future perusal.

MAKE | How-To: Coffee Can Radar.

22Aug/110

Real Sound Cookery – Make a contact mic with baking soda and cream of tartar. | leafcutterjohn.com

A couple of months ago, Collin's Lab featured a story about making your own piezoelectric crystals from Rochelle salt. Collin stopped short of making an actual microphone though: he just demonstrated that the salt crystal would generate a series of voltage spikes when whacked with the handle of a screwdriver. Leafcutter John followed pretty much the same recipe to make crystals of his own, and then clamped the crystal between the jaws of a little panvise, and hooked it to an audio amplifier. When a small music box was held near the crystal, a surprisingly high fidelity recording resulted. Check it out!

Real Sound Cookery - Make a contact mic with baking soda and cream of tartar. | leafcutterjohn.com.

22Aug/110

Yawcam – Yet Another Webcam Software

At various times, I've wanted to set up a little webcam server, but hadn't really found a program which combines ease of use with versatility. But today, I found a mention for the program "Yawcam", a Windows only webcam software written in Java, and decided to give it a try. Bingo! It works pretty well! It's free, it provides a wide variety of capabilities (including image snaps, video streaming, and a built in webserver). The only real downside is I wish it wasn't on Windows. It's "donationware", check it out if you are in need of something like that.

Yawcam - Yet Another Webcam Software.

Addendum: Here's a picture of Scrappy!

17Aug/110

Another retro computer website…

While researching some information on the old CP/M operating system (don't ask) I found Herb Johnson's excellent retrotechnology.{com,net} website. It's chock full of good information on old Apple Macintosh systems, S-100 systems, and cool virtual exhibit on the PDP-11. Bookmarked for later consumption: tons of good information.

http://www.retrotechnology.com, .net/.

Addendum: It's amazing how often I find people with odd interests have other odd interests that coincide with mine. Herb has also ground and polished his own telescope mirror. Awesome.

15Aug/111

Astronaut Photographs Perseid Meteor

NASA astronaut Ron Garan snapped this awesome picture of a Perseid meteor from his vantage point on the ISS:

Astronaut Photographs Perseid Meteor... From Space : Discovery News

No additional commentary: it speaks for itself.

Filed under: Space 1 Comment
14Aug/110

ARISSAT-1’s battery appears to be failing quicker than expected…

I didn't get a chance to record any more ARISSAT-1 data this weekend, but I did catch up on some reading. Apparently, it's batteries are giving out quicker than expected: the voltage is dropping low enough to cause a reset when the satellite goes into eclipse each orbit. If you were thinking of grabbing some telemetry/SSTV from the satellite, or even attempting some QSOS, perhaps sooner would be better than later.

You can read up on the Power System of the satellite here, which includes a link to this AMSAT Journal article which gave many details. Apparently the silver-zinc batteries which were used aboard the satellite (largely for safety, a dead short of these batteries does not cause a fire) have many features which were seemingly not that well understood. These batteries are typically used in a deep-discharge situation, and only recharged five times. Aboard ARISSAT-1, they are recharged in a shallower cycle, more times. There also seems to be some issues regarding temperature performance. I skimmed the article, but will reread it and rethink it some more soon.

14Aug/111

Arduino PWM Laser Transmitter

A couple of weeks ago, I programmed an Arduino to take digitized sound stored in its rom, and send it out via PWM of an LED. A couple days after that, I used the same code to send voice using a small 5mw laser module. Ever since then, I thought it would be good to use the Arduino's analog to digital converters to sample the sound from a small microphone, and then use that as the signal to send over PWM. Here's my first test:



There is lots of noise remaining in the signal. Some further experimentation showed that the voltage regulation wasn't very good: I did tap 5v from the Arduino, but the load must have been near its limit, because the overall voltage levels were varying by nearly 100 millivolts, which is only slightly less than the signal amplitude. I also have many leads which are too long, poor layout, and unoptimized values for AC blocking caps. But it does seem to work. I'll be revising this over the next couple of weeks.

Addendum: I did measure the current through the op amp preamp, and the laser diode module. The op amp circuit only needs to drive the Arduino input, which is very high impedance, so it draws less than four milliamps. The laser diode averages 20ma, but has a peak power of twice that.

10Aug/110

AMSAT SSTV gallery

I haven't had the chance to do any ARISSAT-1 SSTV lately, but I thought I'd snoop over to their gallery to have a peek. Some good pictures are being received, but it appears that some earlier pictures are simply being removed: two pictures that I submitted to them earlier are no longer available. Their comment:

We may not be able to display every image because of quality or duplication but it is important for you to submit them for engineering analysis purposes. The rest will be archived onto a subsidiary page.

There is no hint of where this subsidiary page can be found. Honestly, AMSAT: if you are going to act as a centralized repository for SSTV images, why not make all received images available? If they are of interest to the principals, they are probably of interest to everyone else too.

Still, surf over and have a peek. But if you find a picture you like, archive it on your local system.

Welcome to the AMSAT SSTV gallery.

8Aug/111

I before E except after Hellschreiber « SWHarden.com

Scott Harden had a very cool idea: sending Hellschreiber, an old fax-like teleprinter code invented by Rudolf Hell, using just an Atmel ATMega48 and a canned oscillator. The idea is pretty simple: the canned oscillator will produce a square wave with the same amplitude as the input voltage. So, you simply power the oscillator with the PWM output (presumably with some low pass filtering) of the AVR, and you can produce a simple AM modulated signal. There are some issues with this, but the basic idea is pretty cool, and I have most of the parts I need to make this happen at home. I'll try it out and let you know how it works out.

>>> I before E except after Hellschreiber « SWHarden.com.

Addendum: I experimented with this basic idea using my LED/Laser PWM code/circuit that I built on my Arduino. I'm uploading the youtube video now, but I realize that now that I didn't do what Scott did, and what he did was somewhat more likely to work better. If you watch my latest YouTube video (uploading now) you can anticipate that I'll be apologizing for my stupidity. My experiment did work, after a fashion, but his idea is somewhat better. Stay tuned.

Addendum2: Here's the video that I shot tonight. It's still horribly wrong, but in the interest of full disclosure, I thought I'd toss it out there. I need to work at understanding the filters and the like, maybe add a buffer, and consider the biasing. What can I say, my eyes were dialated, my brain foggy. The aliased copies I hear at the end are probably not going to be present if I actually did what Scott did. Stay tuned, I'll redo this after some thought.