My English version of blog is lagging. Lagging for more than 5 years. Always try to read Lithuanian version of blog using some translate program. Sorry for this lag.

Now, original posting from 2008…

Sometimes is very usefull to send data to you constructed devices of some other stuff using serial protocol. New computers ofter lack of serial ports and also, almoust all the time there is no need for real serial device with high voltage (+-12V) swing. Typical 21st century serial link is TTL or LVTTL.
For this purpose it is usefull FTDI Chip company’s product FT232. (There is new versions of the chip, but it is old post). It is compatible with USB2.0, theoretical max speed is about 3Mbit/s.

Circuit diagram is very simple- few resistors, capacitors, serial EPROM chip (no need in new chip) and 6MHz crystal oscillator.


I’ve used some PCB design distributed as “GNU”. (?)


It is using standard drivers from chip manufacturer’s site FTDI. All initial setting are programmed using same USB cable, so no need for external eprom programmer.


FT232 PCB and circuit diagram (schematics) for Cadsoft Eagle software.

Link to original Lithuanian site: http://www.vabolis.lt/2008/03/15/ft232/

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Problems with money management?

Recent waves of economic instability caused lots of problems in small business. It was american dream to open new business, make money by your self. But now everybody can get yourself in to the trouble. Why? It is your credit situation.
But for those with bad credit, the prospect of business ownership may seem more like a fantasy than a viable option. While it’s true that bad credit can hurt your chances for raising money, financial resources are still available for those who are willing to look for them. There are lots of resources in the internet about credit, money management, but how to find your own path? How to avoid possible problems- it your own money, do not gamble.
Yes, you can go to your bank and ask for advice. But recent history show, that bank is cheating too. And it is natural, bank’s main assignment is to make more money- it has owner too. So the bank is not the solution…
And if you need to close your venture? How about bankruptcy? How to save more money? How not to make mistake in that jungle of the law? Maybe you need this sort of advice?
And how about lending money to save your business? Just as you would with an outside lender, spell out to family members what you’re trying to do and what they’ll get out of the deal if they lend their financial support.
Find a way to formalize the agreement, perhaps by issuing a promissory note with details on when and how you’ll pay the money back. Another tool that could be helpful is site I found one place, it is rmcn credit services, they may help you to solve lots of your money loosing problems.
Regardless of the method you pursue to raise money, don’t borrow more than you need. A rule of thumb is to take on only debt that directly contributes revenue to your business. So it might make sense to borrow money to hire key staff, but it would be a mistake to borrow to buy a better computer when your current PC still works. The key to starting a business with bad credit is being flexible enough to build slowly, and as your credit rating improves, taking advantage of new avenues of funding.

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PCB world is getting smaller

PCB component are getting smaller and smaller. Hobbyist must learn how to handle such miniature components and how to solder it.
Some small parts are already described in old Lithuanian article about soldering LED driver on selfmade PCB. Next PCB are with tiny traces too…
This is sample from Texas Instruments, TPS61058DRCR- “sync boost converter”. Quite good white LED driver for Liion battery pack. Up to 1A for LED chain.

General view. I repeated PCB image three times in case I’ll have problems with traces.

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VAG COM – connect computer to car

Yeap, time passes and English translation is lagging very much. I’ve already sold this car… Now it is the end of 2011, original post date is 2008…

This is abstract from full Lithuanian article about connecting computer to automobile to check engine, brakes, air bad and other stuff.

As my car made some strange effects, I decided to build adapter and to check it. Also, this could be great article. Now it is cheaper to buy China made device.

Adapter converts K-Line, L-Line, ISO9141 to RS232

Components: MAX232, MC33199, 78L05, one transistor and small stuff.

Big image. Warning, ther is small error in image, but circuit is working! :)

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Dimmer, from the word “n. dim, v. to dim”. Simple device to make light of incandescence lamps lower. Also, used to slow down colector motors. All this started because Lithuanian internet is full of old soviet circuits with archaic components. Meanwhile “other” world is using much better way to dim lamps.

Circuit is copied from real world China made halogen desktop lamp. Power of the lamp was about 100W and this circuit is typical.

Dimmer circuit

In real world this looks like:


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Thaw: time to wind dry snow

It looks like thaw. I think it is perfect time to dry some snow:

I wish you Merry Christmas and Happy New Year!

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Facebook, is it evil?

Just testing system to spam facebook with my weblog posts. It is simple WP plugin and Facebook aplication.
Aplication is working from http://apps.facebook.com/braindump

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WordPress 3 bug

I don’t know very well about php and advanced wordpress technology. But new and clean install of wordpress 3 on my computer failed.
When I go to admin page I see error, that website didn’t respont. Apache returned zero byte answer… it was strange.
In Apache log there are lines like this:

[Fri Jul 16 21:53:27 2010] [error] [client x.x.x.x] ALERT - canary mismatch on efree() - heap overflow detected (attacker 'x.x.x.x',
file '/home/testing/public_html/wordpress/wp-admin/includes/template.php', line 3553), referer: http://blog.savel.org/

It is php crash.

So I commented 3553 line and everything is working fine… Now I can see dashboard, users, but I can not see links and other admin pages…

What this fucking line for?

$screen = (object) array('id' => $screen, 'base' => $screen);

My computer is running Linux Debian current stable version. No fancy configurations.
(Server version: Apache/2.2.9 (Debian), Server built: Apr 19 2010 19:57:58.
PHP 5.2.6-1+lenny8 with Suhosin-Patch (cli) (built: Mar 14 2010 08:14:04)
Copyright (c) 1997-2008 The PHP Group
Zend Engine v2.2.0, Copyright (c) 1998-2008 Zend Technologies)

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Pentium 4 cube

What interesting you can do with needless Pentium 4 or similar Celeron processors?

First of all you need to find 6 processors of one type. I wanted to use AMD processor, but dimensions of its housing are a little bit different. Thus I chose 6  Pentium 4 processors, the old ones with small legs.

pentium 4

The following processors were used for the experiment:
Pentium 4, 1.9GHz/256/400/1.75V
Celeron 2.8MHz/256/533
Pentium 4, 1.5GHz/256/400/1.75V
Celeron 1.7GHz/128/400/1.75V
Pentium 4, 2.4GHz/512/533/1.5V
Celeron 2GHz/128/400/1.525V.

pentium 4

All models were quite old. All covers were simply removed for the exception of one. Its crystal was soldered to housing with special solder. This special solder made me some troubles when I soldered the final product:

pentium 4

The cube came out a little bit crooked, but it can roll out several gigahertz and megahertz :)

It’s quite heavy, as housings are made form red copper and nickeled. When you heat one side of it, the other became unsoldered… :)

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Cyclone III

After various financial speculations on the Internet and in real life, I gathered some money and bought through eBay auction Altera Cyclone III Starter Board. Another “starter board” is rambling somewhere in the post.

Cyclone III

I appreciate deeply all my countrymen who bought text mode LCD monitors and thereby sponsored my FPGA studies.

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