[time-nuts] Recording mains frequency/phase [WAS: No GPS satellites]
Charles Steinmetz
csteinmetz at yandex.com
Thu Feb 26 20:39:13 EST 2015
ben wrote:
>I'm going to have to build one of these. Assume you have some sort
>of circuit that converts low-voltage AC from a transformer secondary
>to a pulse train, start a timer, and count x amount of pulses?
Here is a zero-cross detector designed for this purpose:
<http://www.ko4bb.com/manuals/download.php?file=02_GPS_Timing/Simple_AC_Mains_Zero_Crossing_Detector.pdf>
Most mains-nuts feed the ZCD pulse to the DCD line of a PC's RS232
port and use the computer to time-stamp the crossings and append them
to a file of such time stamps.
Alternatively, Tom designed the picPET Precision Event Timer to do
this sort of timestamping:
<http://www.leapsecond.com/pic/picpet.htm>
An Ardu/berry/bone with a flash card can also be used, so you don't
need to leave a PC running.
Best regards,
Charles
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