[time-nuts] TEC party: hardware suggestion

Chris Albertson albertson.chris at gmail.com
Thu Jun 30 16:27:56 UTC 2011


On Thu, Jun 30, 2011 at 1:38 AM, Achim Vollhardt <avollhar at physik.uzh.ch> wrote:
> Time-Nutties,
>
> how about using a small uC (PIC/AVR) clocked with 100ns instruction speed.
> Start = 1PPS from GPS, Stop = 60 Hz Edge? Use internal capture hardware to
> count processor cycles in between.

Recently posted plots show that all you need is an AC wall wart
transformer and two resistors.   a uC is total overkill

The xformer and resistor voltage divider works because by dumb luck
the pin in the rs232 port was designed to accept a signal that looks a
lot like low voltage AC and even better, already has edge detection
built in.  Also by dumb luck someone already wrote the software to
monitor the pin's status and time stamp transitions.     This really
is a case of pure luck.


-- 

Chris Albertson
Redondo Beach, California




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