Novel Zeitgeber devive for antique clock

That's the sort of thing I was thinking of--you might need to put some polyurethane under the clock feet, or something like that.

Many moons ago, Vannevar Bush and John Early Jackson spent part of their retirement improving pendulum clocks, and learned a lot.

Cheers

Phil Hobbs

cuit to make it very accurate. I did not use a sensor, nor did I modify the clock's mechanism or its iron pendulum bob in any way. There is absolutely no circuit or sensor which measures the clock.

ntly.)

I did something like that with a mechanical 30 day windup pendulum clock. I attached a small neodymium magnet to the bottom of the pendulum and pulsed an electromagnet from a crystal oscillator to keep it in sync. Problem is, the thing runs in reverse so the pendulum is controlling the escapement wh eel rather than the other way around. I guess the escapement wheel could be redesigned so the pendulum drives the wheel which would eliminate the need for winding and also 2 or 3 big gears. Look s like a delicate machining pr oblem, and I don't have many tools.

-Bill

The point was to do subharmonic locking, as in a parametric frequency divider. It's a fun idea.

Cheers

Phil Hobbs

You're like Jim. He posts wrong stuff and then blames the readers for not correcting it themselves.

Why is there more to it than that? Because physics is complex.

It's similar to the subharmonic diode oscillator that I posted here a while back:

Quit whining and contribute something on-topic, and I'll have no excuse to continue.

Because Larkin wants you to not take notice of the 1000X gain tacked on the end >:-} ...Jim Thompson

Good grief, it's six standard parts. If you were actually interested, you could enter that yourself in about a minute.

But you aren't interested.

Darn, if you hadn't squealed on me, Fields would never have noticed the E1 1000 thing there in plain sight.

With such a complex circuit, I was hoping he'd miss that part.

How about you? Got anything to say on-topic?

Watch this space >:-} ...Jim Thompson

I'm establishing a new acronym for you... PAL... Pompous Asshole Larkin >:-} ...Jim Thompson

How have you managed to read that an yet not link it to SED's most problem child?

There's an Austin experimenter, Charles Wenzel who built a clock which grbs 60 cycle from air - circuit posted on techlib.com. I think Phil Hobb's idea to make a mechanical injectionthe best, since easy retrofit. A 4 inch speaker is pulsed by 5 V at 60 cps, and hung on back of clock. Could it work at a sub harmonic like 12 cps to be infrasonic? BTW, the clock I have was built in New Haven in 1870. No bearings in it. Still runs. Accuracy +/- 5 minutes a day. It is small, about the size of Phil's book, with a glass door, decoration, etc.

What's the period of the pendulum? Any estimate of the peak-to-peak horizontal swing of the pendulum?

The peak velocity of the pendulum, at the bottom of the swing, is important to the possibility of phase locking to a 60 Hz coil located under the pendumum.

Five minutes per day doesn't sound great for a pendulum clock.

--- The way I'd do it would be to determine the pendulum's period, then apply a single, mains-referenced pulse to a coil located directly below the center of the bob's swing.

There'd be a small bias magnet around which the coil was wound, so that when the bob passed through the static magnetic field it'd generate a small pulse which would be used to determine the bob's position with reference to the mains.

That way, if the bob was early a small pulse would be sent to the coil close to the beginning of the pendulum's next up swing, and if it was late a small pulse would be sent to the coil close to the end of the pendulum's next down swing.

---

--- Can/would you post a photo of the clock with enough detail to show the pendulum, the space around the bob, and the thickness of the housing under the bob, please?

Also, can you determine and post the pendulum's period?

Just stick an ordinary electronic clock to the back of it, remove the hands if you want.

Nor will it change. The handful of bureaucratic jobs involved are quire permanent.

?-)

Fun.. (thread and links) We've got a torsional osicllator that goes at about 1 Hz. Next time one is set up I'll see if I can feed it 60 Hz and get it to lock.

George H.