I acquired an old pendulum regulator from about the 30's-40's and it had an electromagnetic coil and a small magnet attached to the pendulum. Some old electronics passed a constant (but adjustable) current through the coil either pushing or pulling the pendulum slightly to make its amplitude bigger or smaller. This enabled you to make slight adjustments in its period, so you could speed it up or slow it down gently.
I disconnected those electronics and instead passed a small current through from a digital clock built from a microcontroller and a cheap ebay rubidium. This current was periodic so it gave the pendulum a very slight nudge every swing (like pushing a child on a swing). This worked extremely well and the clock's second hand was spot on (to the eye) for months. Then I moved house and the clock was no longer inside but relegated to the garage where the temperature varies quite a bit (10-30 depending on time of year). The temperature variations overpowered the slight nudges and it no longer keeps good time. I'm seriously toying with the idea of putting a small heater in the cabinet, so I can have an OCPO - oven controlled pendulum oscillator. :-) On 12 December 2011 09:13, Don Latham <[email protected]> wrote: > Try: > http://www.bmumford.com/clocks/hj/hj0199.html > and similar stuff found by googling "driving pendulum clock" > Lots of food for thought. Mumford has put some thought into it. > A lot depends on why you want to drive the thing; e.g. measuring > perturbations in the gravitational field, a sensitive barometer, > temperature sensor, etc. etc. > Don > > Brian, WA1ZMS > > This was talked about several years ago, but did anyone get a fully > > functional design running using electromagnets to synch at one or both > > ends of the travel? > > > > In the meantime I am using a sensor to measure the time period of the > > pendulum for this particular new grandmother wall clock and from that, I > > can synthesize a pulse train from one of the 10MHz lab clocks to drive > > the electromagnets to cause a subtle synch at the end(s) of the pendulum > > travel. The pulse train freq is custom for a given clock. > > > > Anyway...... that's my scheme for now. > > Feedback welcome. > > > > -Brian, WA1ZMS > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > -- > "Neither the voice of authority nor the weight of reason and argument > are as significant as experiment, for thence comes quiet to the mind." > R. Bacon > "If you don't know what it is, don't poke it." > Ghost in the Shell > > > Dr. Don Latham AJ7LL > Six Mile Systems LLP > 17850 Six Mile Road > POB 134 > Huson, MT, 59846 > VOX 406-626-4304 > www.lightningforensics.com > www.sixmilesystems.com > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
