Month: December 2005

Electrostatic Headphones

December 4, 2005 by 18 Comments

electrostatic headphones

Most headphones and speakers use electromagnetic force to drive speaker coils. Electrostatic speakers use electrostatic force to modulate a diaphragm. Mylar is used as the diaphragm in these headphones. Two insulating rings sandwich the mylar and a perforated stator is placed on either side. Ideally these stators would be acoustically transparent, but sheets of metal with 2mm (or smaller) holes that make up at least 25% of the area work. Construction problems can arise from glue not sticking to the mylar and the mylar having not enough or too much tension. A special amp has to be built for the headphones to generate a 450V difference between the stators.

[thanks mrdelayer]

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Depth Of Field Machine For DV

December 3, 2005 by 16 Comments

dof

The small footprint of a CCD makes it hard for digital video cameras to emulate the short depth of field of film cameras. You’ll notice depth of field in movies when they have one actor close to the camera and you see the second actor over the shoulder; the actors will alternate being in focus because of the short depth of field. Here are some examples. To emulate this using a DV camera you have to change the size of the target area.  A smaller image is projected on a clear screen in front of the camera which is then recorded. This project uses a clear CD blank for the screen. The CD is rotated using an old CD player; otherwise the camera would pick up the grain of the plastic. Pretty easy, right? I haven’t even mentioned that the resulting image is upside down.

[thanks Angstrom]

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Build Your Own Computer Rack

December 2, 2005 by 32 Comments

rack server

Most geeks dream of rackmounting their gear. The fact that most rack equipment is purchased by companies means it’s way too overpriced. Seriously, $60 for a drawer? The best solution for us is to build our own. Here’s a build from the ground up. It starts with the basic 19″ rack. Then adds fileservers and other components. Make sure you check out the homemade power rails.

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SNES Super FX Overclocking

December 1, 2005 by 12 Comments

SuperFX

marshallh from the benheck.com forums has managed to overclock a Super FX chip. The Super FX was an extra graphics processor included in some Super Nintendo games. Using this chip, games like Star Fox were able to handle polygons and intensive sprite scaling. marshallh removed the 21.4Mhz ceramic resonator from a Vortex cartridge and replaced it with a 24Mhz oscillator and a couple caps. The result is a smoother frame rate and minimal slow down with multiple enemies.

[thanks vb_master]

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