January 24th, 2011 — 12:50pm
I needed a small Linux machine for my wireless network. Apple’s zeroconf (used for automatically setting up printing, file shares, itunes, etc.) implementation (Bonjour) does not work across networks, so I needed a server on the wireless network to advertise the services (print, itunes, etc.) available on the wired network. The router between the networks will forward packets as required. And I happened to have a Soekris net4801 lying around…
The router between the networks would be the ideal location for a Zeroconf server, because it can advertise on both networks. Except that my router runs OpenBSD, and there currently is no working implementation of Zeroconf for it. (The port of Bonjour is underway, but it’s not fully functional; Avahi doesn’t work too well either, due to the dependency on dbus.)
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October 3rd, 2009 — 12:34pm
Appliance: an instrument or appratus for a specific purpose. In other words, an appliance is not a general-purpose machine like a desktop computer. Another term heard occasionally is media-pc. It’s a network end-point in the living room that can play and record audio/video, and is a connection point for USB devices like webcams or memory card readers. It’s silent and has no moving parts, and is controlled primarily with an infra-red remote.
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December 26th, 2008 — 4:56pm
Why does anyone need a headphone amplifier? You can just plug your headphones into the jack on your iPod, can’t you? Yes, of course you can. However there are some high-end headphones that have low impedance — they need more current than the usual high-impedance phones. Often these headphones are low efficiency, meaning for the same loudness they need more input power than more efficient phones. Finally, the output amplifiers in low-power portable devices are often of indifferent quality, particularly at reasonable volume. A headphone amplifier fixes all these problems; and if you make it yourself, you can add extra features like crossover networks.
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February 2nd, 2008 — 11:36pm
GPS is fundamentally a very accurate time-dissemination system. With an appropriate GPS receiver, the clock on a computer can be maintained to within a few milliseconds of UTC. However, consumer GPS units do not provide the “PPS” super-accurate time signal to the computer, because the USB (or serial) connection has no way of transferring it. The OEM version and a little work with a soldering iron is all that’s required. Continue reading »
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January 31st, 2008 — 3:59pm
The infrastructure here is DNS, NTP (stratum 1), and firewall.
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September 16th, 2007 — 9:35pm
A sidereal (L. “of the stars”) tracker is a camera mount that turns at exactly the speed of rotation of the earth but in the other direction, so the stars appear stationary. This allows long exposures of the stars — up to 3 hours with this one. Continue reading »
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June 2nd, 2003 — 12:00pm
What do you get when you put a Logitech QuickCam in the hands of a geek with a bunch of Nikkor (Nikon) lenses? He is dissatisfied with the quality of the optics. Why not replace it with a Nikkor lens, he thinks. It was with me the work of a moment, and now I get excellent optics, good focussing action, aperture control for those difficult lighting conditions, and a super-fast telephoto! The Glen Park Cam no longer works, but here’s a gallery of past images. Continue reading »
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