I just installed a quartz battery movement into a wall clock that once had a mechanical movement. I lost the pendulum capability and I'd like to find a simple circuit that would move the pendulum with the same speed as in a normal clock. I'd like to use the same pendulum the clock used before I replaced the movement, which is 3" diameter bob and 12" long. The circuit would be best powered from a single or double C or D batteries. Anyone have any ideas or links?
Thank you, Bill
they don't get much simpler than this:
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I agree, that's cheap alright but the problem is that I already have a chiming electronic quartz movement installed and I just need a pendulum only driver. The hand shafts would only serve to take up too much space since I already have hands on the current movement.
Bill
I agree, that's cheap alright but the problem is that I already have a chiming electronic quartz movement installed and I just need a pendulum only driver. The hand shafts would only serve to take up too much space since I already have hands on the current movement.
Bill
Find you're self a small DC motor that can support the weight of the pendulum or a helper support for it on the end of the shaft.
Use a 9 Volt battery instead and a 555 timer that turns on the motor for a short burst.. Also at the same time, you can have a reverse polarity detector to determine when the motor is at the end of the back travel. When no voltage is detected, the timer will then be on for a short time, so that it will pull it back again.
The Back motion of the motor generated energy can be used to hold down the RESET pin on the 555 timer. The timer will be a one shot set up, once the timer is done with its short duration, nothing will happen until enough voltage gets back generated to pull the reset pin or you actually pull the pendulum to get it started.
Once you get this in motion, you won't need much to maintain it.
THe timer can handle up to 200 ma output, but I wouldn't push it that hard, you really shouldn't need that much any way depending on your demand.
If you really need a C/D cell operation, I guess one could implement a 2/3 transistor version of a monostable oscillator where the back energy of the motor resets the cycle and starts it over again. That would be an interesting idea.
Jamie
There was an article in Scientific American, sometime in the 80's I think, about using electronics to drive or synchronize a pendulum clock. I believe it described using a solenoid to nudge the pendulum at the appropriate intervals.
Well, there are quartz movements that wag pendulums (maybe you can just buy one and use a link... like a rubber band...) A 12" pendulum with ALL THE WEIGHT AT THE END has a natural period of sqrt(g/L)/(2*pi) = 0.9 seconds so, with a little fiddling (maybe tune the pendulum) it should work with a movement that makes a 1 Hz pendulum output.
A Venerable Clock Is Made Highly Accurate By Equipping It with Quarts-Crystal Works
by C. L. Stong September, 1974
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