blog dds: electronics

2016.05.07

The Computer Tube

I've been reading the book ENIAC in Action, which details the fascinating ten-year history of the first general-purpose programmable electronic computer. In it I found a reference to 7AK7, the so-called computer tube, which improved the reliability of tube computers.

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Last modified: Saturday, May 7, 2016 10:49 pm

2015.12.13

Raspberry Pi vs USB vs Mac Audio

The audio hardware of Raspberry Pi is known to produce relatively poor sound quality. I bought a cheap USB sound card to try as an alternative. Here is what I found.

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Last modified: Sunday, December 13, 2015 1:02 pm

2013.03.30

How to Fix the Sony MDR-W08L Headphones

I love the Sony MDR-W08L headphones, because they are featherlight and the only ones that don't fall from my ears when I run. Sadly, there's no effective strain relief at the point where the cable leaves their body. As a result the cable can become internally severed, and the sound becomes intermittent. Here's how to fix this problem.

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Last modified: Saturday, March 30, 2013 1:51 pm

2011.05.29

Ten Lessons I Learned from Fixing my Laptop's Motherboard

A month ago I managed to break my laptop, by reversing the polarity of a universal power supply. The repair shop diagnosed the problem as a failed motherboard, and asked for €659 to replace it. I found the price preposterous and the notion of throwing away a motherboard for a single failed component ecologically unsound. Here is how I fixed the laptop on my own, and what I learned in the process.

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Last modified: Monday, May 30, 2011 0:14 am

2009.08.20

HP-200LX Remote Control Hacks

All my friends know that for the past 15 years I've been semi-attached to an HP 100LX palmtop PC (recently updated to a 200LX) for my personal information management and many other tasks. The device is extremely versatile, sturdy, and flexible. Amazingly, after so many years of hard daily use, I still find new applications for it.

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Last modified: Friday, August 21, 2009 0:27 am

2009.07.01

Real-Time Google Earth GPS Tracking

In a recent trip I incorrectly assumed that real-time tracking of Google Earth's pre-cached maps with a GPS receiver would be sufficient help for navigating around the highways in Los Angeles. I therefore experimented with the way Google Earth's sparsely-documented real time tracking works, and wrote a small program to interface Google Earth with a GPS receiver. Fortunately, after seeing a colleague drive with a car-GPS device on the dashboard I came to my senses, and got a real Garmin Nuvi car-GPS device.

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Last modified: Wednesday, July 1, 2009 4:42 pm

2009.05.07

Fixing the Orientation of JPEG Photographs

I used to fix the orientation of my photographs through an application that would transpose the compressed JPEG blocks. This had the advantage of avoiding the image degradation of a decompression and a subsequent compression.

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Last modified: Sunday, June 14, 2009 8:20 pm

2009.03.28

Earth Hour: A Geek's View

What happens to the power grid when millions of people turn of their lights? I had a chance to study this during tonight's Earth Hour: an international event organised by the WWF, which asks households and businesses to turn off their non-essential lights and electrical appliances for one hour to raise awareness towards the need to take action on climate change.

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Last modified: Sunday, March 29, 2009 0:01 am

2009.02.18

The Information Train

The Information Train is a scientific experiment that I presented at the Wizards of Science 2009 contest over the past weekend. The entry demonstrates how computers communicate with each other by setting up a network in which a model train transfers a picture's pixels from one computer to the other. You can find a video of the experiment on YouTube, and, if you're interested, you can also download the corresponding software and schematics from this web page.

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Last modified: Wednesday, February 18, 2009 4:21 pm

2007.12.28

Losing the War

The following gem comes from the user manual of the spanky-new Sony Ericsson K770i (3G) mobile phone. It demonstrates amply the state of the art in software engineering as of 2007.

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Last modified: Tuesday, January 1, 2008 4:51 pm

2007.04.21

Modularity and Troubleshooting

A residual current device trips leaving the house in the dark. How do I fix the problem?

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Last modified: Saturday, April 21, 2007 7:06 pm

2006.12.25

The Capacitor Plague Hits a Baby Monitor

Good baby monitors are hard to come by. Many tend to be oversensitive, others switch from squelch mode to transmission with a loud hiss that is more irritating than a baby's cry. We were very satisfied with a Tomy Walkabout Digital 1998 baby monitor, until the day it started emitting a squeaking sound.

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Last modified: Monday, December 25, 2006 12:41 am

2006.09.02

Hardware and Software Debugging

Debuggging day. The MySQL 5.0 server I tried to run as part of a MediaWiki installation under FreeBSD, crashed during initialization, and a Tomy Walkabout digital baby monitor started emitting a low beeping sound. I solved both cases through educated guesses.

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Last modified: Saturday, September 2, 2006 11:47 pm

2006.01.03

Disappearing Hardware

Let's start the new year with a retrospective look at hardware advances. I've ordered some older and current hard disks that were lying around by date. We're taking for granted the increases in disk size, but also impressive is the reduction in size of the control electronics.

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Last modified: Tuesday, January 3, 2006 5:41 pm