[time-nuts] NTP Clock suggestions?
albertson.chris at gmail.com
Mon May 27 14:23:46 EDT 2013
One more idea: Buy one of those "Atomic Clocks" that run off WWVB. Then
use time code to modulate a very low power 60KHz radio transmitter. The
clocks will pick up your signal and sync to it. The clocks run on
battery power and you don't need wires.
But then I did notice you can buy exactly what you asked for $99.
On Mon, May 27, 2013 at 9:40 AM, Bob Camp <lists at rtty.us> wrote:
> If you are doing this from scratch today, would you go IRIG or would you
> go RS-485 for a wall clock? Both will drive more cable than you are likely
> to have in a house. Both are reasonably noise immune. With RS-485 there's
> less to do. It's a serial stream like any other bunch of "stuff" into a
> Some math:
> YYMMDDHHMMSSCR = 13 ASCII characters. With one check byte it would be 14.
> A baud rate of 115.4K isn't stretching things on RS-485 or on most UART's
> these days.
> Sent it at 7N1 you have 9 bits per character, 126 bits in the message.
> Message takes a bit over 1 ms.
> Time it to anywhere in the string and the clock should be within <+/- 2
> ms. That's better than I can see on a clock. Better yet, time it to the
> first (or last) character in the string. More or less a 10X improvement.
> You could also drop the year / month / day if the clock isn't going to use
> Take any of the Arduino (or what ever) LED display boards and drive them
> with something cheap. I doubt the "clock" end plus the drivers would be
> over $30. I suspect IRIG would cost a bit more once you got it all worked
> On May 27, 2013, at 11:03 AM, Chris Albertson <albertson.chris at gmail.com>
> > I've seen LLCD computer monitors used as clocks. Seems this would be
> > the perfect use for a Rasbury Pi. and a cheap monitor. $100 or maybe a
> > low-end Android tablet.
> > The way it is more commonly done is you have you computer that is
> > using NTP produce an IRIG time code. Then there are any number of
> > commercial clocks and large digital LED displays that will use IRIG.
> > IRIG displays are not cheap but they sure are easy to find.
> > On Mon, May 27, 2013 at 6:29 AM, Miguel Barbosa Gonçalves <m at mbg.pt>
> >> Hi!
> >> I was wondering if anyone knows about a not so expensive wall digital
> >> that gets its time from an NTP server...
> >> TIA,
> >> Miguel
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> > --
> > Chris Albertson
> > Redondo Beach, California
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