ljcox said:No-one seems to have mentioned that the natural frequency of the pendulum (ie. it's frequency when it is swinging without the electrical assistance) needs to be as close as possible to the frequency that it is to run at when electrically driven.
Otherwise, it will be impossible to make it sync with the electrical signal from the crystal oscillator (divided down of course).
Instead of a 4017, you could use a presettable counter such as the 74HC161.
This has a synchronous preset. Configure it to preset to 10 (ten) when it reaches 15 (ie. when Tc (pin 15) goes high. It will then be preset to 10 at the next clock pulse. Thus it is a modulo 6 counter.
The advantage of this is that you can use the Tc output (gated with say 0.2 sec) to drive the pendulum pulse.
If you wanted say a modulo 7 counter, then preset to 9, etc.
RODALCO said:Also I'm working at the moment on a external very accurate timebase upon a 4.19 MHz crystal, in Crystal oven.
( Pendulum clocks with invar rods are very accurate, but occasionally may drift a couple of seconds a week. )
4.194.304 MHz divide by 22 gives one Herz.
For a 3/4 seconds pendulum i need 4 complete, or 8 half swings for one impulse per 6 seconds. ( I choose this value because i may use it for 2/3 seconds clocks as well )
I have not got a 1 second pendulum clock at the moment because of the hughe shipping costs to New Zealand $1000 NZ or 700$ US .
I'm thinking along the line of using a CMOS 4017 which counts the 1 seconds impulses from the 4017. decode the 6 seconds, and provide a synchronising impulse to the pendulum.
The 1 second impulse is about 0.2 seconds long.
By AND gating the 0.2 and 6 seconds impulse together to a driver transisitor (2N2222) a impulse can be put into the coil to drive the pendulum.
I haven't got this far yet because of 2 young children at home and long working days, and too much time on the forums i admit, but I will get onto it now sooner because of your interest in this great topic too.
This impulse can't be to strong, because the pendulum is already driven through the graham escapement from the electrically wind clockwork.
What country are you from BTW ?
Regards, Raymond
Do you have the data sheet of the 74HC161?markelectro said:Thanks for this
all sounds very interesting and could be what I'm after But!! sory there is a lot I don't understand in the explination.If you have the time and could expalin in laymans terms I would be very pleased in hearing from you.
agent420 said:Another clock fanatic besides myself... I'm not sure if I should be amused or concerned LOL.
I have been thinking of a similar project, using the natural pendulum cycle to drive a nixie display...
If anyone involved with pendulum projects could explain to me the purpose of the pendulum spring, I'd be grateful... Is it simply to avoid the friction associated with a bearing?
agent420 said:Another clock fanatic besides myself... I'm not sure if I should be amused or concerned LOL.
I have been thinking of a similar project, using the natural pendulum cycle to drive a nixie display...
Have you seen this one? It seems to infer the kinetic art toys I referred to earlier use the same idea... I may pick one up at the local dollar store just to open it up...RODALCO said:I'm also still looking for a good and reliable pendulum trigger circuit so any members with knowledge, please post us a link.
agent420 said:Have you seen this one? It seems to infer the kinetic art toys I referred to earlier use the same idea... I may pick one up at the local dollar store just to open it up...
I'm thinking of incorporating a decent sized relay (open frame for good aesthetic measure) that will be synced with the impulse circuit (or other pendulum counting sensor) to get the audible 'tick-tock'.
I also woke up this morning with another clock face idea based on the old color-changing **broken link removed** from the 70's... Honestly, I should probably see a therapist
Thanks for the info on the suspension spring.
I'd like to avoid any electronic timebase in my project. While I'm sure that such a circuit would no doubt improve the accuracy of the clock, there is just something about a 'natural' timebase that appeals to me. Occasional time (re)setting is just another reason to go play with it LOL. I will however try to make pendulum assembly fairly accurate, probably using invar. I'd love a merc compensated pendulum - how many old thermostats do I need?RODALCO said:They could be useable, especially when a external crystal oscillator is used.
sam2 said:I have a room full of cuckoo clocks, I had to sound proof the room so it didn't drive my wife crazy. 125 clocks all going off at once is a great sound to me.
RODALCO said:Thanks agent 420 and bobledoux for your links.
They could be useable, especially when a external crystal oscillator is used.
Here are a couple of pics taken from the Hipp Toggle mechanism in my Favag 2/3sec masterclock.
https://farm1.static.flickr.com/242/457283586_75faebeb65.jpg Hipp toggle coil
https://farm1.static.flickr.com/237/457283584_5206c6a76b.jpg Hipp toggle coil
https://farm1.static.flickr.com/242/457283582_6ea363324f.jpg Hipp toggle switch
https://farm1.static.flickr.com/175/457283576_9a5e3c900d.jpg Hipp toggle switch
Regards, Raymond
agent420 said:My physics is a bit rusty, but I'm wondering how a microcontroller or other 'smart' impulse method affects the pendulum accuracy... If I understand correctly, a pendulum has a natural oscillation, and it's period is not necessarily related to the length of swing in the arc, but only the length of the pendulum itself.... Meanining that as the pendulum 'slows down' or swings less side to side, it still takes the same amount of time to complete a cycle.
For a one second pendulum, that equates to approximately 39" (**broken link removed**)
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?