μblog: engineering from the trenches

Many of us know that today, the last day of 2007, is the day that this years alcoholic products expire and therefore must be destroyed in some way. Although some prefer to pour these products down the drain, most will yield their bodies to this effort and destroy alcohol through consumption.

Ethanol is the primary active chemical in beers, wines and liquors. There are trace amounts of other alcohols which may alter the drinks effects, however, they are typically the minority. As chemicals go, ethanol (200proof, dehydrated) has a published material safety data sheet. This sheet should be printed out and posted in a conspicuous place at your drinking establishment so that individuals partaking will stay safe. Below are some symptoms, from the MSDS Section III: Hazard Identification, which may indicate to party goers that they are indeed consuming some amounts of ethanol:

Swallowing: May cause dizziness, faintness, drowsiness,
decreased awareness or responsiveness, nausea, vomiting,
staggering gait, lack of coordination, and coma

There is another document available which describes the metabolic mechanism for alcohol (ethanol). The summary is as follows:

• Reduces liver glycolosis,  leads to low blood sugar levels
• Reduces retinal production, leads to temporarily impaired night vision
• Uses water, leads to additional dehydration

So the basic idea is to avoid driving after drinking, space out your drinking over time and make sure you eat, to get adequate sleep with lots of water, and to go for a sweet drink instead of a coffee in the morning. Hopefully, by working together, we can solve this problem of expiring alcohol and have a pleasant New Years Eve.

2007 has been a great year, thanks to everyone for reading and commenting. See you in 2008!

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I can’t help but confess that the past few days, after getting Orange Box for Christmas, have been excellent for me, but a total waste of time for everyone else. I spent the past two days playing Half Life 2 and Portal and not much else.

The apology aside, I have become quite curious about the Nike+iPod gift that June received. The box contains exactly what it shows: one foot sensor and one receiver for the iPod Nano. I have seen a few teardowns (1) (2) and am pretty impressed. Just for the record, neither of the devices are serviceable, so the shoe sensor must be replaced every after every “1000 hours of use“. The basic idea is that the shoe sensor has a piezoelectric sensor to measure acceleration (even though many people think there is a MEMS sensor)  that sends it’s identification code to the iPod receiver. The two are coupled and supported by the latest iPod Nano firmware, which then provides voice notifications and on-line tracking.

Over all, this is a nice technology that demonstrates power conservation practices (runs from a 3.6V li-ion cell). The design is sleek and efficient. I hope to post the details to make an adapter for this device to another shoe brand soon. I hope this did not sound too much like a sales advertisement for you, the smartest reader on the internet, to see.

Finally, there is a paper from U of Washington which basically outlines how to track someone based on their Nike+iPod gear. They outline the serial communication protocol between the attachment and the iPod.

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Reading Bob Pease’s website can be both enlightening as well as entertaining as he recounts the ‘creation’ of the Signetics 9046xN Random Access Write Only Memory. To make a long story short, an engineer in the 1970s got fed up with filling out massive amounts of paperwork when writing datasheets that was not being looked over so he created the write only memory mentioned above. The datasheet can (found here and here) got approved and added into products catalogs from Signetics which were distributed to customers. The management teams realized that the chip was fake (and probably read the datasheet for the first time) when customers started inquiring about pricing and availability. In the end, Signetics decided to take a humorous approach and pay to have the datasheet published as a two-page April fools joke in Electronics Magazine. It seems that many companies have begun to focus on streamlining internal paperwork which would hopefully lead to less disgruntled engineers, however, companies these days seem to have less tolerance for humor. With the ease of on-line publishing, every single company that has any visibility is subjected to some level of ridicule and often makes matters worse by sending cease and desist notices. This makes knowing the difference between parody and libel that much more important than ever.

(  wom.pdf )

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This time, we have the FW82801 from Intel, a part of the i845 chipset. Not much to see here other than the logo. I am hoping to do some more analog circuits in the upcoming weeks so that readers can enjoy a less-busy view. Let me know what you think.

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A little off topic, but some clever researchers at UCLA have created the Gene2Music project where they mapped classical music to genetic sequences and created some MIDI files (as well as sheet music). The image above is from one of the sheet music sections.

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Adding references, or data from, publications that are over a hundred years old seems to be a popular trend among scientific presentations these days. Sometimes it is to give a false sense of scholarship, however, it is often to remind us that some ‘new’ scientific breakthroughs may be simple re-interpretations of old discoveries. I try to note the references and look them up, when time permits. Here is the first paragraph from the preface of ‘Epilepsy and Its Treatments‘ (1904) by Spratling:

 The great progress made in the knowledge of epilepsy and its treatments during the past decade and a half, and in fact that no complete treatise on the subject has appeared in the United States since Echeverria’s work was published thirty-three years ago, was the chief reason that lead to the preparation of this volume.

With the exception of Manuel Echeverria (On Epilepsy: Anatomo-Pathological and Clinical Notes (1870)), the sentence can still be used in a modern book/review of Epilepsy without much alteration. The reason that the 1904 book was cited was to show that, a hundred years ago, physicians were aware that, on very rare occasions, were non-clinical. For example, it was noted that verbal interactions were sometimes enough to bring people out of seizure, something that researchers who seek alternative epilepsy treatments are rediscovering. (On a slight side note, there is an interesting personal account by Feydor Dostoyevsky starting at the bottom of page 466 where he links a pre-seizure state to a state of mental enlightenment.)

This long winded introduction was to present a pair of review articles from the early 1900s that covered what the authors thought were the highest achievements in physics and applied math of the previous century.

1905barus-the-progress-of-phsyics-in-the-nineteenth-century.pdf

1900woodward-the-centurys-progress-in-applied-mathematics.pdf

The image is from the IEEE and is of the Georgetown, CO steam/hydro powerplant.

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This week, we have the Playstation 2 Emotion Engine. Upon doing some background research, I came across this nice article regarding the design of the PS2 memory subsystem by Rambus.  On a side note, I had to subject this chip to an acid bath twice so as not to risk cracking it when I removing the die from the package. The was that some of the surface scratches actually ended up removing part of the metal layer on to and exposing some of the chips innards. Next time I run into a chip that is mostly metal on top, I may try to exploit this technique to remove some of the cover. I might also try to use a UV laser that my department just bought.

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As per my previous post, I have started working out the waveforms to interface a Sony dualshock 2 controller. I decided to go with a Cypress PSoC instead of a standard 8051 because it has a built in SPI controller thereby making the bit-banging much easier. The downside is that I don’t have a C compiler built into the development suite, but that is all right, I am pretty good with assembly. In the process of setting this board up and testing a few things, I found the embedded systems section of wikibooks quite useful. The whole electrical engineering section looks pretty good. The pages can be edited by anonymous readers just as easily as wikipedia, however, I have not found anything terribly wrong in the limited time I spent looking at the site. Over all, it seems like a decent place to learn for beginners and to contribute for experts.

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Ever since I learned to make truckloads of money on the internet, I have been mulling over the idea of buying myself a slim PSP. The main motivation for the purchase would be a few fun games that are PSP exclusives. The problem is that I don’t have any use for the portable aspect of the system and would actually prefer to keep it plugged into the TV. The slim PSP has component output capability, however, you still have to hold the device to play it. While looking at Hack A Day, I saw several ( 1 ) ( 2 ) methods to augment the inputs on the PSP, all involving directly wiring buttons and potentiometers directly to the PSP mainboard. A better option would be to attach a Playstation 1/2 controller port to the PSP so that a wireless PS2 controller can be used. Luckily, Jameco has some tutorials on communicating with the controller. I guess its a good time to get back to work with that 8051 board I built some time ago and see if I can get the interface to work.

( Broken PSP image is from mylife. )

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This week, we have the Graphics Synthesizer chip from Sony’s Playstation 2 game console. The specs on the chip can be readily found, however, I did not see a published datasheet. I expect the emotion engine chip to be imaged in the upcoming weeks.

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