Archive for category Techies & Technology

TechnOlympics

It has been said that the Olympics is rather like a genetic freak-show: All of the extreme outliers from the population show up and do their thing. While specific “genetic gifts” are pretty much required to reach the top of most any sport these days, a little technology can certainly assist in the process. This week’s Electronic Design cover story is The 2008 TechnOlympics and discussed some of the technology that will be used in Beijing.
One item that caught my eye was the increased use of computational fluid dynamics (CFD) software. Although wind tunnel testing has been used on cyclists for some time, CFD software is being used for other areas, including the design and analysis of low-drag swimsuits. Speedo claims that their new LZR suits offer a 10% reduction in passive drag over it’s earlier racing suits. Of course, the passive drag of a suit is only a very small element in the overall performance so it’s not like they’re saying that the race times will drop by 10%, but world-class races are sometimes decided by hundredths of a second, so every little edge counts at that level.
Some might argue that access to wind tunnels and advanced modeling software offers an “unfair advantage”, but a counter argument can be made that it is just another resource in the mix (like whether or not you live and train at altitude). My attitude on this is somewhat mixed, but I will say that once you start throwing advanced technologies at these sorts of problems, the concept of world records kind of falls apart. That is, while it would be perfectly accurate to say “No person has ever run this fast, thrown this far, etc.”, it is also true to say that that does not mean that a former record holder couldn’t have done so given the same technology.
Granted, the IOC could simply decide to “freeze” technology at a certain level, but spectators and fans do like to see world records. A second problem comes in as to where you freeze the technology. For example, we might disallow certain types of running shoes, but then why allow shoes at all? And before you know it, I can’t stop thinking about this:

Yes, well, I mean, (clears throat) you know, four years ago, everyone knew the Italians were coating the insides of their legs with bolinaise, the Russians have been marinating themselves, One of the Germans, Biolek, was caught actually putting, uh, remolarde down his shorts. And the Finns were using tomato flavoured running shoes. Uh, I think there should either be unrestricted garnishing, or a single, Olympic standard mayonnaise.

But let’s not get into the chemical “enhancements” just yet…

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Fun with Resistive Position Sensors

As part of my continuing adventures in drumming symmetry, I have been working on a dual electronic hi-hat pedal. The idea is to have a single hi-hat pad respond equally well to either a left or a right foot pedal. It is similar to having both left and right kick drum pedals. For the hi-hat, this effect is sometimes realized through the use of a switch, but that requires some extra motion and it’s not possible to use both pedals at the same time. These pedals (both an FD-7 and an FD-8) are used with a Roland TD20 drum controller. The hi-hat pedal uses a resistive position sensor to indicate the location of the hi-hat pedal, be it fully up, fully down, or somewhere in between, to the TD20.
So, how do these sensors work? Well, let’s go back to some basics. The electrical resistance of a material depends on the inherent characteristics of that material (its resistivity) and its physical layout:
resistance = resistivity * length / cross-sectional area
In other words, if you take a certain amount of stuff and make it very long and skinny in shape, it will have a much higher resistance than if you shape it short and stout. Below is a photo of the sensor used in the Roland FD-7 (the FD-8 sensor is very similar).
HiHat_ResistiveFilm.jpg

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World’s Largest LED Chandelier

How does a 7000 pound, 35 foot diameter chandelier using high-brightness LEDs sound to you? Well that’s what was installed the other day at the Stanley Theatre in Utica, NY. The manufacturer, Meyda Tiffany based in nearby Yorkville, claims that it is the world’s largest LED chandelier. Here are details from the local newspaper and from an industry magazine.
The Stanley is one of those grand old movie houses from the 1920s, in an opulent style called “Mexican Baroque”. It’s one of the jewels of Central New York. I love going to the place and just looking around. Recently it has undergone a major renovation, including the creation of this world-record lighting fixture. There are two huge advantages to using high brightness LEDs over traditional incandescents: energy efficiency and lifespan. Typical household incandescents last around 1000 hours. By comparison, compact fluorescents last in the neighborhood of 5000 to 7000 hours. LEDs beat both by wide margins, lasting in the vicinity of 50,000 to 100,000 hours.
It is estimated that using traditional incandescents the chandelier would draw around 7400 watts. The LED version draws about 1100 watts for a 6300 watt savings. Assuming the unit is on for 10 hours per day, seven days per week and energy costs 12 cents per kilowatt hour, that’s an annual energy bill savings of nearly $3000. On top of this, the maintenance time is a very small fraction of a traditional system.
Of course, none of this even begins to touch on how beautiful it is.

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World’s Largest LED Chandelier

How does a 7000 pound, 35 foot diameter chandelier using high-brightness LEDs sound to you? Well that’s what was installed the other day at the Stanley Theatre in Utica, NY. The manufacturer, Meyda Tiffany based in nearby Yorkville, claims that it is the world’s largest LED chandelier. Here are details from the local newspaper and from an industry magazine.
The Stanley is one of those grand old movie houses from the 1920s, in an opulent style called “Mexican Baroque”. It’s one of the jewels of Central New York. I love going to the place and just looking around. Recently it has undergone a major renovation, including the creation of this world-record lighting fixture. There are two huge advantages to using high brightness LEDs over traditional incandescents: energy efficiency and lifespan. Typical household incandescents last around 1000 hours. By comparison, compact fluorescents last in the neighborhood of 5000 to 7000 hours. LEDs beat both by wide margins, lasting in the vicinity of 50,000 to 100,000 hours.
It is estimated that using traditional incandescents the chandelier would draw around 7400 watts. The LED version draws about 1100 watts for a 6300 watt savings. Assuming the unit is on for 10 hours per day, seven days per week and energy costs 12 cents per kilowatt hour, that’s an annual energy bill savings of nearly $3000. On top of this, the maintenance time is a very small fraction of a traditional system.
Of course, none of this even begins to touch on how beautiful it is.

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Combining C With Assembly

The latest issue of Embedded Systems Design has an interesting article on combining C code with assembly code for DSP applications. In some cases, they show an ten fold speed up for an assembly plus C implementation versus straight C code.
Now before anyone starts hollering, please remember that embedded programming is not at all like normal desktop application programing. Generally you’re operating in a “slim” (i.e., resource poor) environment. Heck, some embedded processors only have a few hundred bytes of RAM available and you might be talking about a clock frequency of just a few MegaHertz. Squeezing everything as much as possible becomes paramount. For larger apps, C is the standard environment and assembly is sometimes added for time-critical segments. In general, I don’t like to add assembly because it reduces portability and readability, increases code maintenance, and is generally more time-consuming. But I understand places where it is needed. What I think needs to be done, though, is to squeeze as much out of standard C as is possible before going down the assembly path. What follows is an example of two code variations on the ubiquitous string copy function. In C, strings are nothing more than a contiguous packed array of bytes. Both functions do the same thing: they copy bytes from the source string to a destination string until (and including) a null character is reached (which signifies the end of the string). The first variation is the way a newbie would typically approach the problem. First, initialize an array index to 0, and then copy the bytes one at a time, incrementing the index and checking for the null at each iteration. When you reach the null, quit the loop and add a terminating null to the destination. Pretty simple, right?

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DIY Neuro-Motor Experiments: When the Left Hand Knows What the Right is Doing

In previous installments in the DIY NME series, I’ve looked at the application of symmetrical motor patterns using the drum kit. For this entry, the approach is a little different and says something about “handedness” as well. A few months ago I rearranged my semi-symmetrical drum kit into what I call the super symmetrical kit. The original semi-sym kit offered a centered hi-hat and three toms on each side, decreasing in pitch from front-center to rear. The remaining cymbals were arranged in a more-or-less typical configuration for a right-hander (ride to the right, crashes arrayed as desired, but split evenly on left and right sides). Here is photo of the new super-sym kit (either the wide-angle wasn’t quite wide enough or the ceiling wasn’t high enough to get the whole thing):
SuperSymKit.jpg

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DIY Lab Gear: Vibrating String Apparatus

Sometimes I can’t seem to find just the right lab equipment I want for a particular experiment so I design it myself. Such was the case recently for a course I developed and teach entitled Science of Sound. This course is a natural science elective and deals with the physics of audio and acoustics. We start with a few very basic concepts such as harmonic motion. One of the laboratory experiments involves vibrating strings. I like this experiment because students can relate to it as most are at least familiar with guitars and other stringed instruments (the guitar players really like this one). I had some difficulty in designing a good experiment though. The basic idea is to verify the equation for the fundamental vibratory frequency:
VibStrFormula.jpg
where f is the fundamental frequency, l is the string length, T is the tension, and m-sub-l is the mass per unit length of the string.

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Esoteric Audio Cables

A previous post featured a short film about members of the Audiophile Club of Athens and the rather extreme sound systems their members have created. Some members spent in excess of $300,000 to build their systems. You may be wondering just what manner of gear that sort of money would buy, and would it really sound that much better than a more modest (yet still comparatively “high end”) system of say, several thousand dollars. Before we go any further, let me state that in no way am I making fun of the way people spend their money. Heck, I’ve been known to drop some coinage on musical instruments and Kevlar kayaks, things some people find frivolous. No, I’m just interested in whether this gear is sonically superior or simply audio woo.

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USB 3.0

This week’s Electronic Engineering Times features a short article on the upcoming USB 3.0 spec. The main highlight is a target transfer rate of 4 Gigabits/second (10 times the current rate) providing usable data at 300 Megabytes/second. This rate would challenge IEEE 1394 (AKA FireWire). USB 3.0 is being referred to as “Super Speed USB” and will be “hardware agnostic” according to the article, meaning it could be implemented over copper or optical cabling.
This third variant on the USB theme will adopt a new physical layer, splitting data and acknowledge signals onto separate paths. On the downside, it is likely that USB 3.0 will require a reduction in maximum cable lengths from 5 meters to 2 meters.
The USB crowd is claiming that 3.0 will supplant FireWire, but the FireWire folks themselves are hard at work extending the current 800 Megabit/sec transfer to 3.2 Gigabits/sec. The FireWire spec is due out next year while USB 3.0 silicon is expected in 2009.

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A Sale of Two Titles

It was the best of times, it was the worst of times, it was.. Oops. Sorry, already been done. Start again.
The other day I brought up some thoughts concerning the high cost of college textbooks. In the arena of science and engineering there are issues with the fairly narrow audience and resultant low volume, and some difficulties with the used book market. There is, of course, the issue of the publishers. I am going to risk having my snout slapped by biting the hand that feeds me, but hey, I noticed something the other day that has my head spinning anyway.

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Language Trends in Embedded Systems Programming

The latest Embedded Systems Design features an overview of their annual comprehensive programmer’s survey. ESD (an unfortunate acronym for a hardware journal) has offered the same survey for the past few years to engineers and programmers in both the USA and Europe, seeking info on their current and anticipated needs, projects, tools, and the like (N>1000 for the past three surveys). There are many useful tidbits in here but one in particular caught my eye, and that’s the trend in development languages used.

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The High Cost of College Textbooks

We’re a couple weeks into the semester and the ever-popular subject of the cost of textbooks has raised its head. Along with my students, I often wonder why they shell out so much for these works. I think there are several things at play here, but first a little background: I’ve been teaching at the college level for over 25 years and I’ve written a few textbooks myself, for two different publishers: West and Delmar/Thomson Learning (including the ever-exciting Op Amps and Linear Integrated Circuits mentioned on the sidebar, complete with color-coordinated matching laboratory manual). The thoughts that follow are my own and do not necessarily represent those of my publishers, my college, or college bookstore.

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A Mnemonic Device for Electrical Students

Sequences, whether it’s the colors of the rainbow, the names of the planets, or ages of Earth’s geologic past just scream for mnemonic devices such as acronym-sentences. Some of these can be quite entertaining in their own right, and even more entertaining if you make them up yourself. For example, beginning electrical engineering and technology students are faced with the task of memorizing the resistor color code. The code is used to denote the nominal value of resistors with a total of ten colors corresponding to the numerals 0 through 9:

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How Edison are you?

So asks a Web site of the same name, suggesting that another online quiz waits in its wings. Not so, but the site is a wealth of information.
Edison is perhaps most noted among nonscientists for inventing the lightbulb (which, for once, he in fact did not do; he invented the incandescent lamp and ultimately a new power-grid system to take advantage of same) but the man spent his entire life developing new things and improving existing ones.
His first patented invention was an automated vote recorder for Congress, which, it must be said, didn’t keep him from moving from the New York City area to Florida in his later years. Along the way he engineered an improved stock ticker (fittingly, the device which provided him his first financial breakthrough), found a better means of preserving fruit, produced a better typerider, contributed mightily to a burgeoning railroad system, made the jobs of printers and photographers easier, pioneered early voice machines, delved into early automotive and aeronautical technology, and, as they say, much, much more.
The breadth of Edison’s work and its impact on the world is amazing and probably unparalleled in human history. Were a single person to replicate his of the late 19th and early 20th centuries genius today, that hypothetical someone would have to come up with blueprints for a 100-mile-per-gallon-of-ethanol car engine, a 10-GHz hand-held PC, an instant household freezer, and a true hovercraft all in the same couple of decades. Only Edison himself, it would seem, could even design so brilliant and efficient an example of Homo sapiens.
Even if you don’t feel like donating to the Edison Foundation, which produced the Flash-driven Web site, you as a science buff (one assumes) will in perusing the site be captivated by the extent of Edison’s unrelenting contributions to humanity in a very long career.

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Super Low THD+N

On the audio front, National Semiconductor, long a player in analog semiconductors, has announced a couple new op amp families producing a total harmonic distortion plus noise spec of 0.00003%. These devices are aimed squarely at higher end audio applications and also offer a very low voltage noise spec of 2.7 nanovolts per root-Hertz with a flicker noise corner of 60 Hertz. I find these numbers to be pretty impressive, especially considering a starting price of $1.35 per unit in 100′s (up to about $10 depending on package and other details).
During my college days it was something to find devices with THD specs much below 0.1%, and even the best distortion analyzers were at least an order of magnitude above these little op amps. Also, “low noise” devices rarely broke the 5 nV barrier (the venerable 5532 comes to mind) and they almost always had a lower noise corner frequency well above 100 Hz.
In spite of the ready availability of low cost yet high performance analog semiconductors, I am continually amazed at the piss-poor audio quality that some people seem so happy to accept these days (highly compressed MP3s, “phone” audio, cheesy headphones, car subwoofers that are effective at pumping out 70 Hz tones and little else, etc.). We’d have killed for gear with the sort of quality now available. I mean that literally. Killed for it. Not necessarily other people (well maybe, in some cases), but animal sacrifice wouldn’t have been automatically ruled out.
Courtesy of Audio Design Line.

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Cryptography 101

This week’s NOVA Science NOW on PBS has an interesting piece on the Kryptos sculpture in front of CIA headquarters. The segment does a decent job of showing some of the basic techniques used such as substitution and transposition, in just a few minutes.
I am not a cryptographer but it is an area I have studied a little. It’s a great topic to introduce to my first and second year programming students. Some of them really perk up when we start talking about it. Invariably, someone will ask if I can show them how to “crack” protected software. I always tell them that, although I have the knowledge, it would not be ethical. Some of them give me strange looks at this point.

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Apple iPhone Guts

Curious about what’s inside an iPhone? Well, the good folks at Audio Design Line (via EE Times) have a teardown.
Mind you, it’s not like the old days when you could just pop off the cover of your new electronic doohickey and look at the manufacturer’s part numbers on the chips. These are the days of self-branded ICs. So what did the folks at the technology evaluation/investigation company Semiconductor Insights do?

To get inside the chips, SI resorted to decapping, a process that involves immersing the chips in acid to dissolve the outer packaging and then manually scraping away any residual packaging material.

Sounds like fun! Check out the video of SI’s teardown:

I must admit that I had a little sinking feeling after reading this:

Despite the phone’s “external simplicity and serene look and feel, the internal implementation is actually quite complex,” he said. “There are many secondary operations, fastener screws and difficult orientations needed for final assembly, making the manufacture of the iPhone in China a near-must.”

Not only can’t we afford to make socks in the US anymore, it seems we can’t afford to make almost anything that isn’t prohibitively expensive to ship.

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She Blinded Me With Mobile XMF

Here’s an interesting piece from Audio Design Line regarding a new file format just released from Beatnik. The format is said to produce files one-tenth the size of MP3 files and is intended for narrow bandwidth phones in emerging markets.

The format, called Mobile XMF, would work in conjunction with Beatnik’s music player, which would have to be preinstalled on the phone. Beatnik believes there’s a market for music downloads in Eastern European countries, China, Latin America, and India, where manufacturers sell lots of low-cost phones.

I sometimes hear students listening to music on their phones in the halls of the college. I find most of it unlistenable, not due to musical aesthetics, but due to the horrid audio quality. But, I imagine where the choice is between nothing and something, something wins even if highest quality is nowhere to be seen. I hope Beatnik’s offering makes a worthwhile improvement.
FYI: Beatnik was founded by Thomas Dolby of “She Blinded Me With Science” fame.

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Multitasking, Part 1

Back around 1987 I picked up a Commodore Amiga 1000. This was an interesting little box for home computers of the day. In the late eighties the typical home/office PC was running MS-DOS and had a whopping 640k bytes of memory. The Amiga didn’t look like the average home computer and it certainly didn’t behave like one. For starters, it had a graphical user interface (popularized by the Mac a year or two earlier) and a two button mouse. Unlike the average Mac, it was color (4096 color palette). Further, it had a choice of screen resolutions including 640×400 interlaced. While those numbers might seem comical today, twenty years ago it was something to behold.

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Multitasking, Part 1

Back around 1987 I picked up a Commodore Amiga 1000. This was an interesting little box for home computers of the day. In the late eighties the typical home/office PC was running MS-DOS and had a whopping 640k bytes of memory. The Amiga didn’t look like the average home computer and it certainly didn’t behave like one. For starters, it had a graphical user interface (popularized by the Mac a year or two earlier) and a two button mouse. Unlike the average Mac, it was color (4096 color palette). Further, it had a choice of screen resolutions including 640×400 interlaced. While those numbers might seem comical today, twenty years ago it was something to behold.

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