Global Geek Tour: Yongsan computer parts stores in Seonin Plaza

The computer parts market in Seonin Plaza is awe inspiring. There’s a flea market of vendors surround the building, and inside there’s more than a hundred shops on multiple floors selling mother boards, graphics cards, memory, hard drives, monitors, cases, MODer bling, and more.

Most stores in Yongsan sell the same kind of consumer electronics that you find anywhere – TVs, MP3 players, cellphones, household appliances. Seonin Plaza is the real gem, more unique and diverse than the component market in the basement of ETLand. There’s computer stuff on a scale unlike anything we’ve seen before.

We cross referenced the price of new graphics cards, motherboards, and other parts with Google Shopping results. Prices are generally the same as online shops in the US, but they weren’t lower. Imagine picking up a replacement motherboard at online prices locally, instead of waiting for Newegg to deliver.

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Global Geek Tour: Yongsan electronic component stores

We’re computer geeks and gadget freaks like anyone else, but we always make a beeline for the component stores. It’s the stuff with the most serious geek factor, and the kind of thing we don’t have at home.

The basement floor of ETLand is a maze with 50 or 60 component shops. All were in small glass offices with bags and boxes of parts everywhere. In most shops the inventory is on display in the glass walls, and you ask for the stuff you need. Nothing is clearly priced. This can be a bit tough on foreign visitors, but everyone seemed patient while we communicated using a calculator.

There’s tons of through hole parts and connectors, like in Akihabara. Unlike Akihabara, the selection of surface mount parts is immense. Not just reels of passives, but reels of connectors, chips, microcontrollers, and more.

Prices are comparable to your local electronics shop, and not as cheap as Mouser, Digikey, or eBay. Go to get instant gratification or hands-on time with parts, don’t expect a bargain. Best time to visit seems to be 10-5 Monday to Friday.

More about ETLand’s basement electronics shops below the fold.

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Global Geek Tour: Overview of Yongsan electronics market

Yongsan is probably Seoul’s best known electronics market. The market is made up of a sprawling group of 5-6 floor buildings around Yongsan station, as well as temporary stands and flea markets outside. Each area has hundreds of small electronics retailers, as well as a heavy presence of fried Korean street food.

You’ll find a huge variety of electronics, mostly computers, video games, cell phones, and household appliances. Electronic components are limited to one floor of one building, but the selection is impressive. Stacks of high-end GPUs, the same cards that get bought in bulk by crypto live dealer casinos and rendering operations, were going cheap. Prices overall are cheap compared to other places in South Korea, but with exchange rates and brick-and-mortar markups it’s still way cheaper to buy stuff at home online.

The overview map is made from our notes, see the full version (and Inkscape source) on the wiki.

  • ETLand: electronic parts (basement), computers, cellphones, cameras (top)
  • Najin Arcade: new and retro video games
  • Seonin Plaza: computer parts, mother boards, graphics cards, memory, etc, computer paradise. Amazing selection!
  • Terminal Shopping Center: computers, cellphones, cameras, MP3 players
  • EPark Mall: computers, cellphones, cameras, MP3 players
  • Yongsan Station: metro and train station. Find the exit and turn right

All this info is also on our Global Geek Tour Seoul Google Maps layer. Load it on your phone or print it before taking your own tour.

Pictures of the main buildings below the break. Detailed posts on our favorites are next.

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Global Geek Tour: Scouting the markets in Seoul, South Korea

Fly thirty hours round trip to spend 48 hours scouting electronics markets in Seoul? Yeah, we did that.

Seoul isn’t known for its markets like Tokyo or Shenzhen – that’s right, markets, we discovered more than one – but with electronics giants like Samsung based here there’s a huge and thriving scene. It’s totally different than Akihabara in Tokyo, and we’ll be able compare it to the SEG market in a few weeks.

Later this year we’ll make the actual Global Geek Tour video in Seoul. Shooting the Akihabara video we learned it’s about impossible to finish in one trip. There’s too many unknowns, and most of us spend the first trip gawking speechless. Scouting the location is essential, and this weekend we had a tiny window to do that.

All day we’ll run photos from the electronics markets of Seoul. We shot some video too, look for that on Thursday.

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From the forum: A handful of Dangerous Prototypes

BrentBXR shared his collection of Dangerous Prototypes. He also started a challenge in the forum asking if anyone has more:

I actually forgot two things in this image: my CPLD board and my shirt but was to lazy to retake it. and in a few days; a IR toy wil be added to that (free PCB I already got the parts; I special ordered all of them from digi (in one single order makes it easier), which means in a couple more weeks; another.. and another..)

So the challenge:
Who can ‘handful of DP’ more then me!

I don’t quite understand why I am so attracted do dangerousprototype products.. I guess because its quite what I wish I could do.. This is my kind of projects; from the BP to the BB… To the OBLS. I dont like blinking LEDs like so many hobbiests… I dont like making midi sounds like so many hobbiests… I dont like accelorometers like so many hobbiests… I like digital playgrounds. I like hacking other peoples work. I like making things happen that arnt supposed to happen.

Thanks Brent, your support is very much appreciated. Via the forum

Extending the RAM memory of a PIC microcontroller

Dilshan designed a RAM memory extender for PIC microcontrollers. The circuit uses some logic ICs and SRAM memory modules to extend the data memory of a PIC. The designer provided source code for this project written for the MikroC compiler.

With this given schematic user may be able to address RAM space up to 192KB. But this can be extended up to 448KB by adding more SRAM modules to the system. In this given setup we use 24512 – 64K x 8 CMOS SRAMs as a memory modules. 74HC373 latch is used as 8bit to 16bit address extender and 74HC138 demultiplexer is used as memory bank selector.

Free O’Reilly webcast: Developing Webbots and Spiders


O’Reilly is offering a free webcast on March 13, 2012, at 10:00 AM PT on the subject of Developing Webbots and Spiders: Using virtual robots to automate your work. Among the topics to be covered by this one hour presentation by author and DEFCON presenter Michael Schrenk include the basics of building a webbot, considering online property rights, scraping difficult websites, and maintaining stealth, and large-scale deployment of distributed webbots.

You can register for this free webcast by visiting the O’Reilly Community webpage.

Digitally adjustable precision reference driven via PWM

This simple circuit that converts a 5V PWM signal into a variable precision reference voltage with a rang of -2.5V to +2.5V.  Many designs, like a digitally controlled power supply, programmable dummy load, etc, require a Digital to Analog Converter to supply a stable reference votlage. This circuit is cheaper and requires less pins from a microcontroller.

The circuit described here uses the ubiquitous LM431 shunt regulator to implement a second-order Sallen-Key low pass filter together with a level shifter (see the figure). Compared to the traditional approach, it provides a far sharper roll-off along with a low-impedance output, bipolar output. It will produce a –2.5- to +2.5-V output with a 0- to 5-V PWM signal input. The value of VOut is equal to (5 V × dc) – 2.5 V, where dc is the PWM duty from 0.0 to 1.0 (0% to 100%).

Thanks Adrian! Via Twitter.

Hacking the FPGA bitstream


Squok writes referring us to several documents he’s found regarding hacking the bitstream in secure FPGAs:

In order to protect the intellectual property and to prevent fraud, e.g., by cloning an FPGA or manipulating its content, many current FPGAs employ a bitstream encryption feature, which is advertised by manufacturers as “making it virtually impossible for thieves to steal your design data”, like in the now-retired white paper WP261 from Xilinx… However, this assertion has been breached by researchers using “Power Analysis Attacks”.

Such attacks are outlined in these papers discussing bitstream decompilation and Extracting Keys from Xilinx Virtex-II FPGAs.

Via the contact form.

3D model: USB LCD Backpack v1a

Our latest 3D model is the USB LCD Backpack v1a. We continue to play around in Kerkythea 3D rendering software. We received a nice tip from Squonk about using the soften edges tool in SketchUp for better results. He also made a very good model of a USB mini-B jack, which we shamelessly used in our model above. Thanks Squonk.

The models will be published in the Dangerous Prototypes 3D warehouse collection. They are also uploaded to our SVN. You can find them inside the “art” folders in the respective project folders. Check out the 3D view below. You can zoom and rotate the model. (3D Warehouse still hasn’t rendered the 3D view, we’ll update the post as soon as it does)

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Circuit Lab: Sketch, simulate, and share schematics

Circuit Lab is a online electronics design suite, incorporating schematic design and simulation. It’s free of charge, and allows you to share your designs online.

CircuitLab is a suite of web-based electronics design tools, including the first web-based circuit simulator with the power and accuracy needed for board-level design tasks. Explore example circuits and draw your own schematics…

Thanks Moder! Via the contact form.

CoolRunner-II breakout free PCB build

Cosminnci built a free CoolRunner-II breakout board. CPLDs are programmable logic gate arrays which allow you to build custom logic devices simply by programing them.

If you build a free PCB we’ll send you another one! Blog about it, post a picture on Flicker, whatever – we’ll send you a coupon code for the free PCB drawer.

Get the CoolRunner-II development board for $15 and XC9572XL dev-board  for $15.

Via the forum.

App note: Basic features of the Atmel XMEGA Direct Memory Access Controller (DMAC)

Here is an app note describing how to use the Direct Memory Access Controller found on Atmel’s XMEGA microcontrollers.

This application note covers the basic features of the Atmel  XMEGA Direct Memory Access Controller (DMAC). The goal for  this training is to getting started with simple memory transfers  almost without using CPU time, and reading and writing to  peripherals with hardly any CPU intervention.

Free PCB Sunday: Pick your PCB

We go through a lot of prototype PCBs, and end up with lots of extras that we’ll never use. Every Sunday we give away a few PCBs from one of our past or future projects, or a related prototype. Our PCBs are made through Seeed Studio’s Fusion board service.

This week two random commenters will get a coupon code for the free PCB drawer tomorrow morning. Pick your own PCB.

You get unlimited free PCBs now – finish one and we’ll send you another!

Don’t forget there’s free PCBs three times every week:

  • Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
  • Facebook PCB Friday. Free PCBs while you wait for the weekend
  • Free PCB Sunday, right here on the blog

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App note: Lowering power consumption on PIC microcontrollers

Microchip presents several of techniques for lowering the power consumption of their PIC microcontrollers and dsPIC digital signal processors. Many things can apply to any low-power project.

This document seeks to simplify the transition to low-power applications by providing a  single location for the foundations of low-power design for embedded systems. The  examples discussed in this document will focus on power consumption from the  viewpoint  of the microcontroller (MCU). As the brain of the application, the MCU  typically consumes the most power and has the most control over the system power  consumption.

MIME celebrates 20th anniversary


March 11, 2012 is the 20th anniversary of the first use of the Multipurpose Internet Mail Extension (MIME) protocol. The MIME standard is the foundation of all email attachments and it was first used on March 11, 1992 by Nathaniel Borenstein, pictured above. So when you attach a zipped up load of docs to your next email, you can thank Nathaniel for this contribution to open source code.

Here’s a link to an early copy of the MIME RFC2045 doc.

Via AllThingsDigital.

App note: Current controlled boost driver for long LED strings

This reference design from Maxim is a current controlled boost driver designed for long strings of LEDs. Driving many LEDs in series has advantages over driving them in parallel. In a parallel configuration each LED will need it’s own current limiting resistor or current control, while the series LEDs  make use of a single current controlled power supply. The driver must support the combined voltage of all the LEDs in the string. The reference design can supply up to 100 volts, which translates to around 30 LEDs.

2011 DCC: Bluetooth for microcontrollers


This talk from the 2011 DCC conference held in Baltimore, MD, last September, covers the basics of using Bluetooth in microcontroller circuits. The presenter is John A. Hansen, amateur radio licensee W2FS, and is the developer of commercial amateur radio digital products with his TNC-X company. If nothing else, you’ll find out how Bluetooth got its name.

App note: Analog and digital conversion handbook

Ultrasounder let us know about this free online data conversion handbook from Analog Devices. It covers everything you’ll need to get started with analog-to-digital and digital-to-analog converters. It’s not just reference designs, but also theory on how various architectures function.

The Data Conversion Handbook, edited by Walt Kester  (Newnes, 2005), is written for design engineers who routinely use data converters and related circuitry. Comprising Data Converter History, Fundamentals of Sampled Data Systems, Data Converter Architectures, Data Converter Process Technology, Testing Data Converters, Interfacing to Data Converters, Data Converter Support Circuits, Data Converter Applications, and Hardware Design Techniques, it may be the ultimate expression of product “augmentation” as it relates to data converters. The last chapter discusses practical issues, including common pitfalls and solutions related to the non-ideal properties of passive components.

Via the comments.