Current Regulator Circuit

Yippee! I successfully remembered my training as an electrical engineering student, and built a current regulating circuit to guarantee constant illumination from an LED under varying supply voltages.

(application: RC car headlights)

I won't bore you with a circuit schematic ;-) but it involves two LEDs each having a Vf of 2.0 V and an If of 20ma, a 75 ohm resistor, and a 10k resistor (though it probably oughta be 1k). The resistor values need to be adjusted for the Vbe of the 2n3904 transistor (~0.75 V under these conditions), but the goal is to guarantee 20ma through the LED on the top, for a Vs of 4 to 6V.

Quick Drying Random Things

Ever need something dried quickly, but can't microwave it, stick it in the oven, or put it in the clothes dryer? Try this!

Just tape a hair dryer into the opening of a PAPER grocery bag, put the thing to dry inside, and partially tape it shut. Turn on the hair dryer, and wait a couple of minutes. Whala!!

Zooming in GNU Octave under Ubuntu

Yay, I finally solved my problem! I can now zoom in Octave plots using the mouse (currently on Ubuntu 10.04 LTS).

I found the solution here

...but here it is so you don't have to scroll through all of that:

Build gnuplot with:
./configure --enable-volatile-data
make
sudo make install

and if necessary change the gnuplot's path in octave with:
gnuplot_binary ("/usr/local/bin/gnuplot") 

Just use the right mouse button to select the first point, then click a second time to select the other corner. Whala! Press "a" to go back to the original zoom level, and press "h" to dump some help out to the Octave terminal window.

Enjoy!

Pastebin Python Test

This is just a test of code-embedding from pastebin.com:



Did it work?

Mini Home Theater

Check out my sweet new mini home-entertainment system! I used to be into the whole "11-channel surround, 10,000W subwoofer" etc... thing, but in my old age, have decided most of that stuff is a gimmick. All you need are some decent speakers, well shielded cables, and a high-res (1080p) screen up close, so you can actually see the pixels. This system uses a PC (hidden under the end-table) hooked in through an HDMI input, running Ubuntu so I can surf the web. My keyboard is wireless, and has a built-in track-pad to minimize device juggling. The speakers are M-Audio powered monitors, which do a good job down to about 80 Hz... chosen to maximize audio quality while minimizing space consumption and neighbor-annoyance.

NASA Myths

http://www.fas.org/spp/eprint/jp_950525.htm

The Linux Prayer

Our Torvalds, who art in Finland
Hallowed be thy code
Thy kernel come
thou art half done
on AMD as it is in X86
And give us this release our bug fixes
And forgive us our half-assed bug reports
As we forgive those whose patches aren't fixes.
And insmod us not into kernel taint
But deliver us from Microsoft.
For mine is the license
And the source
Forever GPL'd
Ramen




  from Reddit/Linux, composed by multiple authors