What explains the counter-intuitive numbering of chip pins?
One of the first things one learns in electronics is how chip pins are numbered. In the common dual in-line package (DIP) pin numbering starts from the left side of a notch appearing on the top of the package and continues counterclockwise until it reaches the other side of the notch. Why are pins counter-intuitively numbered in a rotating fashion rather than by columns as one would expect for a rectangular package? And why is the numbering not following the direction of a clock's numbers? I think that both decisions can be traced back to history.
Continue reading "What explains the counter-intuitive numbering of chip pins?"
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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Raspberry Pi vs USB vs Mac Audio
The audio hardware of Raspberry Pi is
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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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
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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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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HP-200LX Remote Control Hacks
All my friends know that for the past 15 years I've been semi-attached
(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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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
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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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Earth Hour: A Geek's View
What happens to the power grid when millions of people turn of their
I had a chance to study this during tonight's
event organised by the
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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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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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
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Modularity and Troubleshooting
A residual current device trips leaving the house in the dark.
How do I fix the problem?
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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
We were very satisfied with a Tomy Walkabout Digital
1998 baby monitor, until the day it started emitting a squeaking
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Hardware and Software Debugging
5.0 server I tried to run as part of a
MediaWiki installation under
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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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
We're taking for granted the increases in disk size, but also
impressive is the reduction in size of the control electronics.
Continue reading "Disappearing Hardware"