[time-nuts] Electronically Disciplined Mechanical Pendulum
Several years ago (OK, the last millenium) I GPS disciplined a friend of mines 200 year old grandfather clock that she had inherited. I used a solenoid to nudge the pendulum. Surprisingly, it worked quite well the first time. The biggest problem was the pendulum did not swing at a 1Hz rate. I think it was needed like 24 pulses/minute.I later played with using a magnet/electromagnet instead of the solenoid, but it did not seem to work as well. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Electronically Disciplined Mechanical Pendulum
Bert, Thank you for posting your project info! One of my hobbies is collecting and repairing clocks. For several years I've been thinking of making an add-on device to discipline pendulum clocks. I've been using PIC based circuits to provide pendulum impulse. I've not tried to discipline the rate as you've done. You said that your circuit had problems locking the pendulum rate when you used an aluminum pendulum rod. Now that you have an oak rod I was wondering if your pendulum would remain locked when you turned off the temperature control. With an oak rod and no temperature control your pendulum would have temperature stability similar to common pendulum clocks. If your circuit can maintain lock without temperature control that tells me that it should be possible to discipline a common pendulum clock using this method. I'm sorry, I'm asking you to perform another test on your pendulum. Can it maintain lock with normal temperature changes? Let it run for a few days with the heater off and see what happens. Also, You may want to try something other than a hard drive bearing to suspend your pendulum. Since your circuit is line powered this is not a big problem. I've performed tests with several pendulum suspension methods including the head support arm bearing from a hard drive. The hard drive bearing performed poorly. You'll need less power to keep it swinging with other suspension methods. Using the hard drive bearing, my pendulum had a Q factor of about 2,000. Using various traditional clock pendulum suspension springs the Q ranged from 5,000 to 13,000. With a crossed wire suspension the Q was 28,000. Finally, below is a link to some pictures of my clock project. I want this to be a traditional style master clock. Something that my wife won't complain about if I put it in the living room! I don't have the skills or machine tools needed to build a completely mechanical master clock. Electromagnetic impulse is my current choice. http://mesterhome.com/clock/picpend/index.html -- Luke Mester http://mesterhome.com/ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Electronically Disciplined Mechanical Pendulum
On 06/08/2015 01:11 PM, Bert, VE2ZAZ wrote: I just want to let those who are curious about disciplining a mechanical pendulum Hello Bert, It is good seeing this in motion. I have had this project in mind since I read the article in Scientific American, A Venerable Clock Is Made Highly Accurate By Equipping It with Quarts-Crystal Works., September 1974. Wall clock of Seth Thomas manufacture, modified by Laurance M. Leeds. Recently I bought a working pendulum clock with the notion of doing the same, but with modern electronics and a closed loop feedback method, LEDs and sensors, rather than open loop as in the article. It is such a beautiful clock though, and it ticks so nicely, I wonder if I should mess with it even if all my electronics is invisible. The SA article really is titled with Quarts. .. my first post here, a test as well. Ian, G4ICV, AB2GR -- ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Electronically Disciplined Mechanical Pendulum
Greetings, I just want to let those who are curious about disciplining a mechanical pendulum that I have pretty much wrapped up playing with a 1m-long pendulum, which I control with PIC micro firmware and try to mainain at a constant temperature. Accuracy for 20-second averaging is typically better than 1 ppm. I have documented my work here: On my website ( http://ve2zaz.net/Pendulum_Ctl/Pendulum_Ctl.htm ), On Youtube ( https://www.youtube.com/watch?v=7NdGX4A8W88 ) Thanks, Bert, VE2ZAZ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Electronically Disciplined Mechanical Pendulum
Hi Bert, Thanks for posting that project. What a wonderful combination of electronic and mechanical timing, of design and measurement, of hardware and software, of PICs and Python. One side experiment that would be interesting is to collect a couple of days of data using a fixed drive and then compare that with the same number of days using your adaptive FLL drive. The resulting phase or rate or ADEV plots would be amazing. /tvb - Original Message - From: Bert, VE2ZAZ ve2...@yahoo.ca To: time-nuts@febo.com Sent: Monday, June 08, 2015 10:11 AM Subject: [time-nuts] Electronically Disciplined Mechanical Pendulum Greetings, I just want to let those who are curious about disciplining a mechanical pendulum that I have pretty much wrapped up playing with a 1m-long pendulum, which I control with PIC micro firmware and try to mainain at a constant temperature. Accuracy for 20-second averaging is typically better than 1 ppm. I have documented my work here: On my website ( http://ve2zaz.net/Pendulum_Ctl/Pendulum_Ctl.htm ), On Youtube ( https://www.youtube.com/watch?v=7NdGX4A8W88 ) Thanks, Bert, VE2ZAZ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
