Okay, so, maybe this blog thing that's so popular with the young people today could work for me.  It seems like an attractive format for presenting some of the interesting stuff going on.

So I'll try this for a while, and see how it goes.  Enjoy...

(Later... registered comments are now set up.)

October 06, 2009
New Solar Panel Looks Familiar

An article in the New York Times, September 27, 2009, Solar Power, Without All Those Panels by Anne Eisenberg, describes solar panels that are remarkably similar to what I proposed in this blog 20 months in my post Solar Valley, The Unsolved Solar Panel Problem, Doubling the Efficiency.


Posted by DonTillman at 10:05 PM | Comments (0)
October 30, 2008
Analog Heaven / TechShop

I stopped by the Analog Heaven Bay Area Gathering this past Saturday. It was a lovely little event with all sorts of modular synths on display; Moog, Arp, Buchla, SynthTech, Wiard, Blacet, Doepfer, and of course, original home-brew equipment. Very cool. I didn't take any photos, but there are some here, here, here, and video here.

This took place at the TechShop, which is a spectacularly interesting place. It's a large warehousey building in nearby Menlo Park set up with large rooms filled with all sorts of serious tools. Grinders, band saws, a drill press, lathe, milling machine, welders, plasma cutter, laser cutter, 3D printer, press brake, shear, punch, and lots more. They run it like a health club; membership costs around $100.00 a month and you get access to everything.

They also offer classes in using the equipment. This makes sense for safety, for minimizing damage to the tools, and for members to get the most out of the equipment. Again, it's a health club model; one can damage body parts just as easily on a drill press as on a bench press.

I believe that the TechShop is also indicative of the new cycle of hobbyist builders. Home built projects and equipment were very popular in the 60's and 70's. I was very much into the electronics side with Heathkits and Popular Electronics magazine. In the 80's and 90's the practice faded as you could often purchase most imported mass-produced products far cheaper than you could possibly build them. But now building seems to be coming back with the Maker Faires, Scrapheap Challange / Junkyard Wars, BattleBots, the Steampunk movement, and of course, MythBusters. In fact the founder of TechShop used to work with Adam and Jamie.

TechShop isn't some dinky community tool sharing resource, it's a serious business. They're working on franchises in other locations. How cool is that? A creative entrepreneurial business that's used by start up creative entrepreneurial businesses to build prototypes and models.

More TechShop:

I'm not going to be joining just yet; I just don't have enough time to devote to building right now. But maybe sometime in the not-too-distant future.

Posted by DonTillman at 12:17 AM | Comments (0)
May 15, 2008
Leno / Tesla

Jay Leno test drives the Tesla Roadster and provides this report.

Posted by DonTillman at 10:40 AM | Comments (0)
February 24, 2008
Solar Valley, The Unsolved Solar Panel Problem, Doubling the Efficiency

Solar Valley

A recent New York Times article describes some of the solar power work going on in Silicon Valley:

The New York Times: Silicon Valley Starts to Turn Its Face to the Sun

Can Silicon Valley become a world leader in cheap and ubiquitous solar panels for the masses?  Given the valley's tremendous success in recent years with such down-to-earth products as search engines and music players, tackling solar power might seem improbable.  Yet some of the valley's best brains are captivated by the challenge, and they hope to put the development of solar technologies onto a faster track.

The valley is amazing.  On a related note...

The Other Unsolved Solar Panel Problem

Besides efficiency and price, there's one additional problem with solar panels that absolutely needs to be solved before they're used in any appreciable quantity: I'm talking about the ugliness.  Solar panels are simply too ugly to install on someone's home.  The current models look all the world like a billboard blew over in a storm and landed on the roof.  That's just not good.

Yeah, I know there are photovoltaic "shingles" available, but those are more expensive, and hand wiring each shingle is awkward and unreliable.

I think the solution will be along the lines of making the leap from considering a solar panel as "something you bolt on up there" to an integral part of the house construction.  I'm imagining something like actual roof sections that are designed to be pretty and functional as roofs just as much as they're designed to be solar panels.  They would replace the roof, instead of being tossed on top of the roof.

How to Double the Efficiency of Solar Panels

Here's an idea for any of the local Silicon Valley (or anywhere else, I don't care) solar energy statups: a photovoltaic panel and a solar water heater combined into one unit.

Photovoltaic panels generate electricity, they're dark colored, and they heat up.  Solar water heaters are dark colored, they heat up, and they warm the water piped through them.  There's no reason you couldn't do both functions at once, effectively doubling the efficiency of the system.  (Especially if you normally have an electric hot water heater.)

It's a freebie, go for it.

Posted by DonTillman at 08:25 PM | Comments (0)
October 01, 2007
jwz on Backups

Jamie Zawinski provides an excellent disk backup procedure.

Posted by DonTillman at 09:06 PM | Comments (0)
September 15, 2007
Solitaire in Web 2.0

Here's a solitaire game in a web browser:


Yeah, it's a solitaire game.  But Web2.0 fans will want to be sure to note that the game is written entirely in HTML, JavaScript and StyleSheets.  Cool, eh?

It's also the latest step in the grand march from binary executable apps to web browser apps.  Google's got their web versions of Word and Excel, but now this guy goes and ports the single most popular Windows app to Web 2.0.  ('Ironic how an insignificant game might be considered a significant milestone, eh?)

Posted by DonTillman at 08:33 AM | Comments (0)
September 02, 2007
ARP Synthesizer Patents Update

An update to my ARP Sythesizer Patents article.  Leroy Young, one of the developers of the ARP Avatar Guitar Synthesizer got in touch with me a while ago and clued me into his patent which became the core of the pitch extractor system.  So that's two patents for the Avatar that don't mention ARP Instruments.  Weird.

Posted by DonTillman at 08:56 AM | Comments (0)
July 16, 2007
Tufte Seminar

Charles Joseph Minard's map of Napoleon's March to Moscow

'Went to Edward Tufte's remarkable experimental two-day seminar last week in P'Alto. He covered most chapters of all four of his books in depth, with many delightful stories, insights and examples. Also the story of how he came to self-publish the books. And he included "office hours" segments to answer individual questions.

I came with away these main points:

  • In reference to pie charts, et al: "Graphics can do more than present the obvious to idiots."
  • One must be true to the data and do whatever it takes to present the data in the clearest way possible.
  • People tend to get stuck in the assumed limitations and cliches of a given medium, and one might have to use one's creativity to break free of that for a better presentation of the data.
  • Presentations should serve the data and not the medium.
  • Clarity comes from more information, not less.
  • It's possible to pack an awful lot more information in a presentation than you'd expect.

ET brought in and displayed several rare first editions of books by Galileo, Euclid and others, which clearly proved how data visualization can break free of the most primitive presentation technologies. (And then you can compare that to PowerPoint.)


Edward Tufte's web site: edwardtufte.com

The always fascinating Ask ET Forum

The books:

All are highly recommended, especially the books.

(The image above is bad copy of Charles Joseph Minard's map of Napoleon's March to Moscow, which has sort of become ET's icon.)

Posted by DonTillman at 12:38 PM | Comments (0)
September 04, 2006
Transparent Computer Screens

Here's a photo of my desk at work, showing off my Mac with the transparent screen option.  (I cleaned up the desk a bit before taking this shot.)

Transparent Mac!

And here's a remarkable collection of photos of computers with transparent screens:


Sure, this is silly.  But it's also a lot of fun.

The real question is, Why are almost all of these transparent screens running on Macs?  One possiblity is that Macintosh fans would be more likely to do something like this.  Another is that Macs still have some mystique that contributes to the illusion; it's almost believable that a Mac would have a transparent screen option.

Posted by DonTillman at 10:02 AM | Comments (0)
Who Killed the Atomic Car?

Following up on my previous...

Here's a great article on the Ford Nucleon Atomic Automobile from DamnInteresting.com, which itself is a very cool site.  Don sez, check it out.

Posted by DonTillman at 09:14 AM | Comments (0)
August 16, 2006
Electric Cars!

Who Killed the Electric Car? The movie Who Killed the Electric Car? was released recently.  I have not seen it, but from the reviews and the trailer and all, it's pretty clear that the film is a documentary of how General Motors ended the EV-1 electric car project.

I took an EV-1 for a quick test drive around town some years ago, and indeed, it's a fine little car.  It's remarkably zippy and quiet.  There's no transmission.  And starting it up is very cool, the dashboard lights come up with computer noises like the freakin' Starship Enterprise (but, of course!).  It's too small to be practical for someone like me; I doubt I could fit any musical instruments in it, and that's the main feature I look for in a vehicle.  But my personal needs aren't necessarily typical.

Regardless of the movie viewing experience, I'll claim that dwelling on GM's screwups is simply not productive.  Let's be honest, we have never expected GM to do anything innovative in car design.  When I think of GM I think of the Corvair, or the General Lee on the Dukes of Hazard.  Who cares that GM killed their electric car project for whatever crazy reasons?

(On the other hand, I am disappointed that Volkswagen has not addressed the electric car yet.  Especially considering that VW models have always been popular for electric car conversion projects.  I expect innovation from VW, but that's a different story.)

Tesla Motors What I do think is important is that a Silicon Valley company called Tesla Motors is taking the bull by the horns and actually going into production with a very cool electric sports car.  And while this particular model is too small to fit any musical instruments, it might very well be successful.

(The car is also pretty expensive, sure, but their business plan involves starting at the high end and working down the price range with manufacturing experience.)

Interestingly enough, the premiere of the movie (June 28, 2006) and the introduction of the Tesla Motors car (July 20, 2006) are both within two weeks of Nikola Tesla's 150th birthday (July 9, 2006). (!!!)

Wrightspeed And there's more...  Another Silicon Valley company called Wrightspeed is also working on a high performance electric sports car.

So, let us review... General Motors created a respectable electric car and, for whatever mysterious reasons, decided to abandon the project, and some guy went to the trouble of making a film about it, and two Silicon Valley companies are actually making significant progress at serious electric vehicles.  There ya go.

But there's an important socio-political concept here... I've noticed that there exists this human tendancy to take some difficult problem or task and hand it off, trusting it to some organization that clearly is not competent enough to deal with the problem, perhaps in the process even fostering a dependency on this organization, declaring the problem solved, and then later getting all pissy when things haven't worked out.  We need a word for this behavior.  It's closely related to that classic definition of madness, "performing some act over and over again, expecting a different result".  Maybe "delusional" is the word.

So yeah, expecting GM to develop an innovative electric car and then whining about it when they don't is an example of this.  Another example would be like demanding that the federal government be responsible for providing your health care and then complaining when the very entity that you don't trust to deliver the mail screws things up badly.  Or expecting anything positive from the United Nations.

The Silicon Valley approach is not like that.  Instead we get out there, roll up our sleeves, apply some innovative and do what needs to be done. It's optimism, it's positive, it's progress, and it's where the truly rewarding opportunities lie.

Posted by DonTillman at 11:54 PM | Comments (0)
July 20, 2006
Sudoku, cont'd

More on Sudoku; a continuation of my previous post.

I see they've updated the Shortest Sudoku Solver site; now the winner is a 134 character Ruby program.  That's very impressive.

The algorithm they use is actually a very straightforward and brute force approach.  (Make a recursive tree for trying each of the empty spaces with the digits 1..9, test each case, return the first one that works.)  But in reducing the character count the programs are obfuscated to the point where they're nearly impossible to figure out.

For instance, at the very end of the Python function definition, they want to write:

for m in '123456789'


for m in range(1,10)

But instead they save a single character by utilizing this little gem:

for m in '%d'%5**18

With somewhat reduced efficiency.  (5^18 is 3814697265625.)  Man, oh man...

Of course I'm really tempted to write and submit a Lisp version of the Sudoku Solver.

Or better yet, APL.  I'll bet there's an amazingly tiny APL solution.  And unlike the Ruby and Python approaches, the APL version might be readable.  Well, no less readible than any other APL program :-).  Unfortunately I haven't looked at the language for several decades, so I'm probably not the one to do this.

(For you youngsters, APL is a computer language that was created in 1962.  The Wikipedia APL entry does an impressive job of describing it.  The language is completely insane.  In several ways.)

Since the Sudoku programs presented on that page are brute force approaches, they're really slow.  Really, really slow.  So I'm thinking it's John Henry time.  Man Vs. Machine.  Sunday!  Funny cars!

So I tried it, and it turns out that the Python program takes several hours to run on a real world Sudoku puzzle.  So that's plenty of time to beat the computer.  (Feh, that takes all the fun out of it.)

Posted by DonTillman at 01:48 AM | Comments (0)
July 14, 2006

I find myself somewhat addicted to Sudoku; it's a fantastically clever little game.  And the kids have become pretty good at it too.  Here Gregor is doing a puzzle before he goes to bed.

Gregor doing Sudoku Gregor doing Sudoku close

Sudoku has achieved an amazing level of pupularity.  In fact, I'll claim Sudoku is the only thing keeping newspaper circulation from completely plummeting.  Pretty amazing when you think about it, a computer just streams'm out, and that's been keeping the newspaper inducstry afloat.

Solving a Sudoku also gives me a funny feeling of Schroedinger's cat.  (Huh?)  I mean, there is exactly one solution, but while you're solving it there can be a number of simultaneous potentional solutions floating around, each with an equal probability of existing.  And as you solve it you narrow down the selection of possible parallel universes, providing them with logical reasons not to exist.  (Okay, it's a stretch.)

The local daily newspaper prints puzzles from KrazyDad.com.  (KrazyDad.com is a completely amazing web site all by itself.  Seriously, check it out.)

Being a professional engineer for a long time, I've been on both ends of an awful lot of job interviews.  And technical engineering interview questions have always been a big part the interview process.  The screwiest interview question have been referred to as "Microsoft Interview Questions" or "Google Interview Questions".  (See http://www.techinterview.org for some fun examples.)

Well, I think Sudoku is fertile ground for some wicked engineering interview questions:

Here's today's Sudoku.   Solve it.   You have 20 minutes.  While I stare at you in a menacing manner.

How would you write a program to solve a Sudoku puzzle?

The brute force approach takes too long; how about with a set of algorithms?

How would you write a program to create a Sudoku puzzle?

First, how would you write a program to generate the solved puzzle?

Then, how would you leave out a set of numbers yet still be assured that the puzzle has exactly one solution?

How would you assign an easy/medium/hard rating to the puzzle?

What is the most blank numbers a Sudoku puzzle can have and still be solvable?

Interesting stuff, eh?

And here is an example of a Python program to solve Sudoku puzzles that has been distilled down to 178 characters (!!!).

Posted by DonTillman at 05:43 PM | Comments (0)
May 05, 2006
Doonesbury does analog circuit design (!!!)

Yesterday's Doonesbury comic features Thevenin equivalents.  I'm not kidding:


That's just not something you see every day.

(Sure, it's badly worded, but still...)

Later... Tim notices this later strip:


Posted by DonTillman at 07:41 PM | Comments (0)
January 21, 2006
The Zen of CSS Design, cont'd

More on The Zen of CSS Design...

Again, the book is The Zen of CSS Design by Dave Shea and Molly Holzschlag.  And the companion web site is http://www.CSSZenGarden.com.  I'm really liking this book and I recommend it highly for anybody doing any web development.  For one thing, it's really well written.  The authors can go from the touchy feely aspects of light and shadow to the grubby details of getting around browser CSS incompatibilities without missing a beat.  I like how they use each example page as a springboard for discussion.  And the Zen Garden designs are inspirational and fun.

So inspirational, that I've decided to move my little corner of the interweb from "HTML 4.01 Transitional" to "XHTML 1.0 Strict" gradually as I update things.  (Although this blog is "XHTML 1.0 Transitional" and will remain so, because blogs are so much more practical that way.)


So a couple weeks ago I rewrote all 26 pages (!!!) of the BayProg site as XHTML 1.0 Strict.  Anything remotely presentation-like has been moved to Style Sheets.  The frames have been torn down and replaced with "Server Side Includes" material.  Lists of items are presented in a nicer and more consistant way.  The menubar implementation has moved from JavaScript to CSS, and it uses "Image Replacement" for the images.  I also did a nicer implementation of the album dropshadows.

Overall it went pretty smoothly, and now the BayProg is a bit cleaner, slicker, and should be compatible with mobile devices.

ARP Synthesizer Patents Article

Two additional ARP synthesizer patents have been discovered; the patent for the ARP Avatar Guitar Synthesizer (thanks MikeI!) and a patent for a low-tech polyphonic keyboard (thanks Armand Pascetta!).  So I wrote up reviews of those, converted the ARP Patents article to XHTML, and prettied it up a bit.

So there ya go.

Posted by DonTillman at 08:53 AM | Comments (0)
December 22, 2005
Digg, Shape of Days, Zen of CSS, Inspiration

Some random bits for the day...

For one thing, I'm finding Digg to be a nice little alternative to SlashDot for generally nerdy technically oriented interweb news and ideas.

The Shape of Days Check out this blog called The Shape of Days.  It's written by a fellow in Dallas named Jeff Harrell.

For one thing, the web design is stunningly beautiful.

But he's got some very interesting ideas there.  I'm especially intrigued by his hack that automatically adds dropshadows to all images using JavaScript and CSS (!!!).  I'm not sure if it's really the most *proper* way to do it, but it sure is slick.

And I like his writing on politics.  And other random stuff.

[Later: Sad to report that The Shape of Days is no longer. The domain now hosts some childish anonymous Democratic party propaganda site.]

Zen Last week I picked up a book called The Zen of CSS Design.  It's a collection of notes and analysis for the Zen Garden CSS project.

Now... I didn't know about this.  Here check it out: http://www.CSSZenGarden.com.

What they did was create an HTML web page with some basic content, and then challanged web artists and designers to make creative presentations out of it.  The trick is that the presentations had to be implmented entirely in Style Sheets, and the HTML page itself could not be changed at all.  That's quite a challange, and since true artists love challanges and limitations, the results are pretty remarkable.

Some of my favorites are:

Oh, and for contrast, the original page is here.

Impressive, eh?

(I guess I'm going to have to apply some of this soon.)

Posted by DonTillman at 01:10 PM | Comments (0)
November 18, 2005

Riverbed Time for a new job!  Starting this week I am working for a small-but-successful-and-rapidly-growing startup called Riverbed Technology.  I'm leading a serious UI project.  It was a tough choice between Riverbed and NetApp, with some interest from Yahoo, Google, and some others...  But Riverbed seemed to have the strongest energy and opportunities.

By the way, we're hiring.  Lots.  Check the website for a list of openings.  The positions are in Mountain View or San Francisco.

And more importantly, I'm hiring.  I'm looking for a couple really good software engineers with significant web-based UI expertise.  Get in touch if you're interested.

Posted by DonTillman at 12:40 AM | Comments (0)
November 10, 2005
Silicon Valley Goings-on

The high tech business environment in Silicon Valley is mighty impressive.  And living here in the middle of it is very excing.  I mean, within a 10 mile radius you can find Sun Microsystems, Apple Computer, Google, Yahoo, Oracle, Hewlett-Packard, and a whole bunch of others I'm not thinking about right now.  And all around there are oodles of venture capital firms fueling future businesses.  You just don't see this anywhere else.

So, here are some of my favorite links that follow what's going on in the Silicon Valley high tech business.  Enjoy.

General tech business news:

Inside the tech economy, a spinoff from the San Jose Mercury News

Good Morning Silicon Valley
Silicon Valley tech news (with the most entertaining headlines ever)

Silicon Valley Watcher
The business of Silicon Valley

Silicon Beat
News about tech money and innovation.

Including Dan Gillmor's blog.

Venture Capital links:

Early Stage VC
Peter Rip's Venture Capital blog

A random walk down Sand Hill Road

Silicon Valley Daily
Silicon Valley business headlines (not exactly daily).

Silicon Valley Venture Capital Firms
'Might not be definitive, but it's pretty close.

This is my first draft of the list, there's lots more I'm sure.  Feel encouraged to contribute your favorites.

Posted by DonTillman at 10:12 AM | Comments (0)
June 10, 2005
Last of the OTA's

OTA's There has been a lot of fearmongering from the electronic music crowd for a long time about electronic music parts going out of production.  Usually it's just a case of some guys who are naturally kind'a jumpy.  However, this one looks serious; Intersil has recently set the status of the CA3280 Operational Transconductance Amplifier to "To Be Discontinued".

"What you talkin' bout Willis?"

An Operational Transconductance Amplifier ("OTA") is something like an opamp, but is really quite different.  It's an amplifier; and like an opamp it has a pair of differential inputs and a single output.  But the output is a current source instead of a voltage source.  The gain of the amplifier is expressed as a transconductance (current out / voltage in), and that gain is programmable because it is proportional to the current going into a gain programming pin.  While opamps are almost always implementing some function by the use of a specific feedback network, the OTA is very often used open loop (or partially open loop).

OTA's are perfect for a multitude of electronic music applications because they can control a parameter, such as amplifier gain or filter frequency, and control it very accurately over a range of at least three decades.

The first OTA chip was the RCA CA3080 introduced around 1969 or so.  The current OTA of choice is the CA3280 introduced roughly around 1971.  By a complex series of corporate megers and acquisitions, GE bought Intersil and formed GE Semiconductor, GE then bought the entire RCA Corp. and merged the two semiconductor groups, GE sold the combined semiconductor group to Harris, Harris sold all assets to a management buyout group, which reorganized things and chose the name "Intersil" for the new company.  Or something like that; I was napping at the time.

So here's my recent email conversation with Intersil support on the matter:


I see from the Intersil web site that the CA3280 and CA3280A Tranconductance Amplifiers have been scheduled to be discontinued. I want to suggest that these chips are too important to retire.

1. The RCA/GE/Harris/Intersil line of Operatational Transconductance Amplifiers used to include the following chips:

CA3080 -- basic single OTA, used for most examples of OTA operation and applications

CA3060 -- triple OTA

CA3094 -- OTA with simple output buffer

CA3280 -- dual deluxe OTA

The CA3080 was discontinued recently, the CA3060 and CA3094 were discontinued previously. So right now, the CA3280 is the last of of the Intersil OTA's.

The 3280 is clearly the most advanced and flexible. It features a very nice input diode linearization circuit, low noise, low offset voltage, and it comes in matched pairs. None of the other chips comes close in these areas, so if you can only support one OTA chip, that's the one.

The 3280 is also capable of functionally replacing any of the other OTA models, ignoring the obvious pin-compatibility issues.

There are not many alternatives available from other manufacturers. For instance:

LM13600 -- dual OTA with simple diode linearization and simple buffer

LM13700 -- ditto

The LM13600 has been discontinued. Neither the LM13600 nor the LM13700 has the performance of the CA3280.

2. There are many audio electronics applications for the 3280, and while admitedly most audio is digital now, the analog alternatives are where the high-end markets lie. ("Reproduction" is mostly digital, put "production" is mostly analog.)

3. The 3280 is invaluable in electronic music work. It's the preferred chip for voltage controlled oscillators, voltage controlled filters, voltage controlled amplifiers, waveform shaping, modulation, signal processing, routing and control, chaos circuits, simulation of mechanical systems, and so forth. And there is currently a resurgance in modular analog music synthesizers (SynthTech, Synthesizers.com, Buchla, Cyndustries, Blacet, Doepfor, Oakley, etc.).

4. Along those lines, the 3280 is inspirational for new designs. For example, my Quadrature Trapezoid thru-Zero Voltage Control Oscillator, my Interpolating Scanner and my Voltage Controlled Duty Cycle Sawtooth Circuit (http://www.till.com/articles) are all innovative designs inspired by the CA3280. And I have a significant number of additional applications in the pipeline.

5. I predict that if the CA3280 is not discontinued, sales will pick up as the supplies of the other OTA chips drop off and the choice of which OTA to use narrows, with the resurgance of audio and electronic music applications, and with new applications being developed.

In summary, I think it would be a big win to keep the CA3280 in production, for all the standard business reasons, but also because the chip is culturally and educationally important, and it would give Intersil a great repuation.

Thanks for listening.

-- Don Tillman
   Engineer, consultant, writer, musician
   Palo Alto, CA

I received a response the next morning:

Dear Don,

I will pass on your concerns but please understand, these CA family of products were developed by RCA on a very old and obsolete fab process that is long since been discontinued and the fab plant was shut down and sold off. We have been living on wafer stock. Today the wafer stock has been depleted to the point we have to withdraw the product. We need to insure we have enough product remaining to support the life time buys that are now incoming.

So, we reluctantly must withdraw these CA parts as our stock is depleted and in good faith, notify our customer base in time for last time buys.

Intersil corp.

I tried for a few more details:

Thanks for passing my comments on.

The CA series parts are certainly old; I think most of them were introduced before the Nixon administration (!!!).

Do you know if another company (like the one that purchased the old fab equipment) is considering carrying on producction when the current stock depletes?

Or would Intersil consider introducing an improved 21st century version of the the CA3280, made in a modern fab?

-- Don Tillman

And received this the next morning:


We are sorry but what FAB equiptment we did not move to Florida, we sold with the building. The CA process was based on an old 7 micron specialized process. So, the process is gone and is not worth the time and 10's of millions to rebuild when today we are working with sub micron processes. The market size for the CA part just will not return a profit for the cost.

As for other sources, I would start with our obsolete distributor, Rochester Electronics.  You might consider looking at Analog Devices, Linear Technology or Maxim for alternatives.

Hokay, well...  I don't blame Intersil.  The process used to make those chips is very old and has been handed down through a number of corporate buyouts.  And I'm sure the CA3280 hasn't been their top seller.  Still, this sucks.

Also, this appears to affect the entire CA line which, besides the four OTA's, includes transistor arrays, opamps, video amps, amps with unusual circuit configurations and taps, special purpose radio and television circuits, and so forth.  Most of these are somewhat antiquated designs and have few practical uses today.  The transistor arrays are certainly nice, but given how easy it is to hand-match transistors, I don't see an array of less-than-great transistors on a chip as an especially compelling story.  But the OTA's are a serious loss.

What to do?  Well, several things:

  • For one, there are a lot of CA3280's still available, maybe hundreds of thousands, and that should meet demand for a while.  Concerned electronic music folks could make "lifetime buys" and do fine.

  • I have a number of projects and articles in the pipeline that use CA3280's, and I'll keep on course with those.  (Although, admitedly, one project uses dozens of CA3280's; we'll have to see how that one goes.)

  • Use the LM13700; it's not as good, but it's still in production and second sourced.  (It might actually work for my dozens-of-OTA's project.)

  • The guys who the fab was sold to?  Oh, never mind...

  • Try to get other foundries to manufacture OTA chips.  OTA's are general purpose devices, not specific to electronic music applications, so the demand should be enough to support at least one good one.

  • Build discrete OTA's.  OTA's are not complex devices, although a substantial amount of hand matching of transistor will be required, but that's not difficult.  Heck, the original Moog modulars were all discrete.

  • This is also an opportunity to build a better discrete OTA.  I might do that; it could have a lower noise input stage, built in exponential conversion for the programming current, a better linearization circuit, better current mirrors, that sort of thing.

And... this is a wonderful opportunity for another semiconductor manufacturer to build a 21st century version of the CA3280.  Are you listening Analog Devices National, On Semicondcuctor, THAT Corp., Linear Technology?  Or even Intersil.  I'll be happy to consult on such a project.

Posted by DonTillman at 11:10 PM | Comments (11)
May 24, 2005
Moog articles update

I've *finally* updated my Moog Resources page and my Moog Patents page.

New streamlined look, modern style sheet display and layout, simplified HTML, better equations with TEX images, added a newly found patent, added some more material, fixed some messy areas, yadda-yadda...

Posted by DonTillman at 07:54 AM | Comments (0)
April 18, 2005
Patent *this*!

This actually happened a long time ago, June 1998, but what the hell... I haven't written it anywhere before.

I was at work, at Marimba at the time, and I was scheduled to interview this fellow for a software engineering position.  His name was Santosh Doss.  And I'm checking over his resume... and lookee here, he's got a patent.

US Patent 5,659,164

I was reading a lot of patents around that time, and I was probably writing my ARP Patents and my Moog Patents articles then.  And also at that time, the IBM Patent Server was the tool to use, so I used that to track down his specific patent so I could look it over.

US Patent 5,659,164:
Method of and System for Apparatus for Two-Way Automatically Creating, Identifying, Routing and Storing Digitally Scanned Documents
Inventors: Edward Schmid, Meridith NH; Santosh Doss, Newton, MA
Filed: Oct. 15, 1996
Granted: August 19, 1997

It's a scheme for doing a batch operation, scanning a stack of paper documents on a document scanner with a feed mechanism, and distributing the resulting images to local files, remote files, email, and so forth. Each document can be one or more pages long.  The patented part is a bar code sticker that is placed in the corner of the first page of each document in the stack, and so after scanning each page, some software detects the presence of the bar code sticker, knows that this is the first page of a new document in the stack, and that it has finished with the previous document, and by reading the bar code it can identify the document and route the resulting scanned image bits to an appropriate place.

Okay, fine.  It sounds pretty obvious, tagging the beginning of each item in a stack has been around forever in some form or another, and bar code stickers have always been designed to be recognizable by computer.  So as such, this sounds like just another one of those obvious patents that should never have been granted.

But... notice anything funny?  Take a closer look at the scan from the US Patent and Trademark Office (USPTO):

US Patent 5,659,164 detail

The image of the scanned patent page shows (and who can't see this coming...) a bar code sticker in the upper right hand corner.

Apparently the patent office has been using this very scheme for years.  That would make sense, being that they clearly have a need to scan stacks of multi-page documents and deposit the resulting image bits into files.

During the interview I asked Santosh about this.  I wanted to make sure that I had correctly interpretted the patent-speak of the text of the patent.  Yep, that's exactly what the patent is for.  I asked him if he had ever heard of the patent being used by anybody.  He said that he hadn't.  I then asked if he ever checked out the image of the patent from the USPTO?  No, he hadn't.  I told him what I found and we had a chuckle over it.

So, not only is the patent office eager to patent the obvious, they're eager to patent stuff that they already use.  I mean, I can imagine walking into the patent office, pointing to a desk, and saying, "I'd like to patent that stapler there".

Now, I suppose it's possible that the bar code procedure could have been put into place after the patent was granted, and maybe Santosh could sue the patent office for the use of his invention that the patent office granted to him before using his invention.  Or maybe the patent office uses the bar code stickers for some other, unrelated, application.  It's hard to say.  But still...

Posted by DonTillman at 05:17 PM | Comments (4)