# Does anyone have any idea how to make this? (see details for image. It's a cool clock....!)

I saw this via stumbleupon and I thought someone may have some Idea how to do it.... Here's hoping!
blog.makezine.com/catenna_clock.jpg

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scarabeetle1017 years ago
use the motor from a clockwork alarm clock. remove all the hands and note where the minute hand attaches. find the sprocket that you want to use, attach it in place of the minute hand, then hang a chain with 12x the number of links than the sprocket has teeth (if that makes sense) from the sprocket. attach the numbers at even intervals, and voila!

I did something similar for a practice GCSE, but with string instead of a chain and various hooks holding the string, but it didn't work because there was friction in all the wrong places...
orksecurity8 years ago
Note that the real trick is getting a motor-speed/sprocket/chain-length combination which causes the _chain_ to complete a rotation in exactly 24 hours. Then all you have to do (hah!) is affix the numbers at the right places.

1 revolution per hour of the gear is by far the simplest solution; that guarantees that the needed chain length will be an integer number of links. But other speeds could be used, if you juggle the math a bit.

Geared-down synchronous AC motors are widely available and fairly cheap, especially if you can scavenge them. That's what I'd try. An ordinary clock motor, with the hour hand sleeve driving the sprocket, *might* work, but I doubt that most clocks would be able to handle that much weight.

Then there's the challenge of figuring out how to affix the numerals to the chain without interfering with its motion ... but that's _relatively_ straightforward.

Should be quite doable. Have fun.
Re-design8 years ago
I found an artical that gave the asking price of the item you show as \$2700.  No wonder you wanted to build on yourself.

Part of the problem is getting a gear with the right number of teeth that will fit your motor shaft.  You need a motor that will rotate approx 1 rotation every hour.  A very robust clock would work very well for this.

But better yet, actually perfect, would be a stepper motor and controller.  You can vary the speed so that it would be very accurate just by changing the timing.

I think a bicycle chain would be too big.  You could probably find a small chain and gear on the net with some searching.  I used to have a small chain that came out of a blueprint machine that would be perfect but too short.  It would have taken several joined to make it long enough.

Divide the chain into 1 equal spaces and attach your numbers.

Enclose it and decorate if as you like.  I don't think the numbers in the photo work very well with the clock as build.  I would find something else.

Good luck.
cook\$ (author)  Re-design8 years ago
Cool. Now I'm gonna have to ask how to build a stepper motor controller and adjust the timing! I'm not really an electronics kinda guy, but willing to have a go. How would I power it is another concern.... any help would be much appreciated!
8 years ago
THen I would get a kit. It would have all of the parts but you would still learn something as you put it together.

You should get your stepper motor first.  There are a couple of kinds.  Some of the controllers won't control all kinds.

You can go to here to take a look at a kit.  I got one of these when I first started looking at steppers.
Sandisk1duo8 years ago
get a washing machine timing motor (the thing that turns the dial when the washing machine is on) then get  alength of chain and a sproket, see how much of the chain turns in an hour.