Bruce Lilly wrote:
On Mon, 05 Mar 2012 20:18:31 +0000, unruh wrote:
The problem is that parallel ports are far rarer than serial ports these
days, and even rarer than usb ports. And you would then have to get the
output of that counter into the computer. A bit more than $100 for the
whole thing I suspect.
Here's an outline of how this can be easily done for far less than $100
of hardware: any parallel output for which a suitable driver exists can
The more I look at this, the more I settle down on using Ethernet as the
communication channel!
Something like the Soekris board reduced to the size of a pack of cards,
with a (timing) gps chip on a daughter card, and an Ethernet port for
communication. Preferably using a cheap TCXO or more expensive OCXO for
local holdover and stability. The TCXO could be synthesized by moving
one of the regular temperature monitoring channels to the crystal. (We
have seen experiments doing this with the normal cpu & hard disk temp
monitors, they seemed to give an order of magnitude reduction in
temperature-induced excursions.)
I.e. the recently posted link to an ntp black box server embedded in an
outdoor-proof antenna enclosure, but a couple of orders of magnitude
cheaper. :-)
Terje
--
- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"
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