Guillaume Filion wrote: > Adrian von Bidder a écrit : > >> Interesting for those whose fascinating with time extends to non-computer >> controlled clocks: >> http://www.admin.cam.ac.uk/offices/communications/1522.html >> (although using LEDs on a mechanical clock is just wrong. I'd like to redo >> this effect using sunlight/mirrors/... without artificial light sources.) Hard to tell time at night, then. You'd have a mechanical sundial. (See also the digital sundial.) >> The clock is absolutely gorgeous, a true masterpiece.
It is. I hate to rain on the parade, though, but its timekeeping seems flawed. In the beginning of the video, the clock strikes three. It takes at least three seconds to do that. (n seconds for n o'clock). When that's finished, it starts indicating seconds again, at one second past. (At the end of the video, the frame is frozen at 11 o'clock; we don't see this struck.) Its day is thus 156 seconds longer than a civil day, so unless its seconds are 156/86400 shorter than TAI seconds, it will lose time. It's not a sidereal clock, as a sidereal day is shorter, not longer. (Of course, maybe nobody notices that, because someone adjusts the clock's pendulum length (just like I do for the cuckoo clock in the hallway) until it agrees with a better clock long-term. This just has to happen at the same 12-hour interval every time.) > The LEDs are not > controlled by any electronic device, they're always lighted and are > shown at the right time by movings slits in the facing. I don't find > that too much of a iconoclasm. :-) > Indeed, they're only LEDs to get power consumption down to 60 watts. I suppose an electroluminescent panel (like almost previous-generation laptops) eats more power. Compact Fluorescents and incandescents even more, but they'd work too. > Here's a similar but totally different clock made with a > microcontroller, an RGB led strip and an hard drive: > http://www.youtube.com/watch?v=K1asNB0te0o > http://www.ian.org/HD-Clock/ > > I find it absolutely fascinating, and it doesn't look too hard to make, > but it'd be very noisy... > > Check out the various scope clocks. Google around. Or start at leapsecond.com. -- Jeff Woolsey {woolsey,[EMAIL PROTECTED],[EMAIL PROTECTED] Nature abhors a straight antenna, a clean lens, and unused storage capacity. "Delete! Delete! OK!" -Dr. Bronner on disk space management _______________________________________________ timekeepers mailing list [email protected] https://fortytwo.ch/mailman/cgi-bin/listinfo/timekeepers
