Hello,
I'd like to get some pointers regarding two projects I intend to start in the near future, concerning analog clocks.
I want to create two different clocks:
- One that has 24 hours (instead of 12)
- One with 12 hours but whose hands turn counterclockwise
Also I don't want to use/hack an existing clock mechanism, but rather build something from scratch.
Can you please give me some tips on how to start? Also: is a microcontroller necessary/useful to this kind of projects (e.g. connected to a RTCC and automatically adjusting for DST, or something), or is it better to set up some kind of steady motor that will do the job itself?
Unfortunately I'm not an expert on using stepper/servo motors, and I thought this could be a fun and cool way to start.
Thanks for reading this,
enjoy.
Both those kinds of motors are not suitable for a clock. You could use a stepper but that's very inefficient. The best place to start is a motor ripped out of an existing clock mechanism.
If you don't want to hack a clock then you are almost in the place where you can't get there from here.
MorganS:
Both those kinds of motors are not suitable for a clock. You could use a stepper but that's very inefficient. The best place to start is a motor ripped out of an existing clock mechanism.
If you don't want to hack a clock then you are almost in the place where you can't get there from here.
Ok, so hacking it is I guess! So it actually boils down to what should I reuse of an existing clock motor and mechanism, and what I should change to achieve what I want…
Thanks
Yes. Not to put you off or tell you is can't be done but starting with something close to what you want is usually best.
MorganS:
Yes. Not to put you off or tell you is can't be done but starting with something close to what you want is usually best.
Well, I really appreciate that you told me how it is, this can be saving some pain.
Thanks
Also I don't want to use/hack an existing clock mechanism, but rather build something from scratch.
Then you are trying to "re-invent the wheel".
One with 12 hours but whose hands turn counterclockwise
That is easy to do. I have such a clock.
All you need to do is remove the pole-piece from the clock's motor, and flip it over.
You might have to do some intricate filing to the pole piece so that you can fit it the other way round, because they are generally designed to be poka yoke.
JohnLincoln:
Then you are trying to "re-invent the wheel".
Ok, point taken.
That is easy to do. I have such a clock.
All you need to do is remove the pole-piece from the clock's motor, and flip it over.
You might have to do some intricate filing to the pole piece so that you can fit it the other way round, because they are generally designed to be poka yoke.
thanks, I'll try and do that
Good idea. I was thinking of turning the whole mechanism over and extending the shafts out the back of the mech. That would be mechanically much more difficult than flipping the motor.
The 24-hour clock just needs the gear ratio between the minutes and seconds hands changed by a factor of two. Yes, you can buy these clocks but cutting your own gears out of icecream box plastic could be quite instructional. Use wooden gears for extra difficulty and extra appearance value when it's hanging on the wall.
The gears would be the most difficult. For 24 hour clock you would need different center gears so the full turn of large hand will move the small hand 1/24 of full rotation.
Programming is easy but projects like this need mechanical work and that is what will cost you.
The easiest option would be to somehow manage to use 2 servos for each hand and then do everything in software.
Picture a pulley, close to another pulley, connected by a belt. If the belt between the pulleys is operating with a half twist in it, the two pulleys are in counter rotation.