Airplanes, hardware, software, jazz
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.
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.
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 »
The infrastructure here is DNS, NTP (stratum 1), and firewall.
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 »
At Languid House, the “home server” is a Linux (RedHat 8) machine with a TV card, infra-red receiver, and a modem (phone) card that understands Caller-ID. The monitor and speakers are in the living room or bedroom but the noisy box is in the next room, with cables going through an outlet hole in the wall. It’s a TV that can be controlled with an ordinary remote (I use an old Sony remote I happened to have lying around). When a phone call comes in and I happen to be watching TV, the caller-ID information appears on the screen. (If I’m not watching TV, then a popup window appears on the screen.) If I decide not to answer, the computer is an answering machine: it plays the outgoing message to the caller and allows them to leave a message. I can listen to messages by viewing a webpage. Continue reading »
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 »