[time-nuts] Regulating a pendulum clock (Jim Palfreyman)

Don Latham djl at montana.com
Mon Aug 9 05:07:59 UTC 2010


----- Original Message ----- 
From: "Jim Palfreyman" <jim77742 at gmail.com>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Sunday, August 08, 2010 6:12 PM
Subject: Re: [time-nuts] Regulating a pendulum clock (Jim Palfreyman)

> Well last night I did a quick and dirty.
> I got my (GPS locked) 3325B to generate square waves (0-5V) at 1 Hz. 500ms
> on. 500ms off. I ran this through a relay that delivered 10mA at 25V to 
> the
> coil.
> By adjusting the phase of the 3325B I got the ON to occur as the magnets
> approached. But I had no idea whether the magnets were attracting or
> repelling at that point.
> Watching the timing of the pendulum it started to radically deviate. I
> concluded it was repelling and so reverse the polarity. It started heading
> back the other way. Cool. As it was late - I went to bed.
> Next morning the pendulum had locked in nicely. It was only deviating a 
> few
> ms either side of a fixed point. I will let this run for today and make 
> sure
> it has settled in and doesn't vary.
> The pendulum clock is fast by 200ms and so I'll adjust the phase to 
> correct
> it tonight.
> Next step will be to drive it properly from my rubidium driven
> microcontroller.
> While I organise that I'll turn off the electromagnet and see if I can 
> pick
> up the tides.
> Regards,
> Jim Palfreyman
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there. 

More information about the time-nuts mailing list