Mystery Clock

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Project by DickB posted 01-20-2012 04:07 AM 5233 views 24 times favorited 15 comments Add to Favorites Watch

This is an exposed wood gear clock project that I am working on. All of the moving parts are out in the open, so you can see everything working, but what makes it tick is a bit of a mystery to many. Unlike most pendulum clocks where the pendulum regulates the movement, in this clock the pendulum drives the movement.

The pendulum contains a rare earth magnet, and the base has a coil of wire in it. As the magnet passes the coil, an electronic circuit senses the magnet and sends a current pulse into the coil. This gives the pendulum a “kick” and keeps it moving.

Others have designed and built clocks like this, but I have developed what I believe to be a unique drive circuit. I use a microcontroller with a watch crystal reference, and compare pendulum period to the crystal reference. Then, I adjust the pulse to the coil to speed up or slow down the pendulum a bit. This makes the clock much more accurate than it otherwise would be. There is also an LED in the base that flashes red or green if the pendulum is too fast or to slow. This makes it easier and quicker to set the pendulum bob.

I’m fine-tuning the design with three clocks built and running at this time.

Here’s a video:

-- Dick,

15 comments so far

View Charles Maxwell's profile

Charles Maxwell

1034 posts in 2779 days

#1 posted 01-20-2012 05:14 AM

Very nice! I’ve built a few clocks as well. I have only done one with a electro-mechanical impulse drive. I use a few transistors to time and impulse the neodymium magnets at the end of the pendulum. I’d be interested in comparing designs. I’m curious as to the battery life of your clock design.

-- Max the "night janitor" at

View DickB's profile


65 posts in 1291 days

#2 posted 01-20-2012 07:04 AM


You have some very beautiful clocks!

Calculated battery life is over a year on 4 D cells. This is my first pendulum clock, and I’ve not had one running long enough to verify. I have had one running for about a month. I was thinking of running one to exhaustion on AAA cells to verify.

-- Dick,

View a1Jim's profile


113462 posts in 2549 days

#3 posted 01-20-2012 07:27 AM

Hi Dick
Welcome to Ljs
That’s one fantastic clock

-- Custom furniture

View tom427cid's profile


294 posts in 1442 days

#4 posted 01-20-2012 09:28 AM


-- "certified sawdust maker"

View StumpyNubs's profile


6538 posts in 1772 days

#5 posted 01-20-2012 04:16 PM


Thanks for posting!
-Jim; aka “Stumpy Nubs”
(The best woodworking show since the invention of wood.)

-- It's the best woodworking show since the invention of wood... New episodes at:

View KYJeepGuy's profile


42 posts in 1413 days

#6 posted 01-20-2012 04:36 PM

Nice job, beautiful work. Which CNC router/engraver do you use?

-- If I'm not in the shop, I'm someplace else. Joel, Lumberjock #30,000

View DickB's profile


65 posts in 1291 days

#7 posted 01-20-2012 08:10 PM

Thanks. CarveWright. Reasonably priced, no extra charge for the basic but very capable software, easiest to use of the software packages that I sampled. Some people have a lot of trouble with the machines, but much can be avoided by using a good dust collection system (which oddly the manufacturer does not provide) and paying attention to maintenance needs.

-- Dick,

View majuvla's profile


5100 posts in 1839 days

#8 posted 01-20-2012 08:13 PM

Awsome.Very good looking

-- Ivan, Croatia, Wooddicted

View Manitario's profile


2386 posts in 1855 days

#9 posted 01-20-2012 08:14 PM

Beautiful clock, very unique motion! Welcome to LJ’s.

-- Sometimes the creative process requires foul language. -- Charles Neil

View Diggerjacks's profile


1923 posts in 2111 days

#10 posted 01-20-2012 08:41 PM


Welcome to LJ’s

This type of project is for me the best of the best for the scroll saw working

I love it

Thanks really for sharing

-- Diggerjack-France ---The only limit is the limit of the mind and the mind has no limit

View bobasaurus's profile


1822 posts in 2156 days

#11 posted 01-21-2012 01:46 AM

Very clever clock mechanism. I want to make one badly.

-- Allen, Colorado

View rhettbarker's profile


6 posts in 1332 days

#12 posted 01-21-2012 08:25 AM

that is awesome you should publish some plans. I have a carvewright and would like to build that.

View DickB's profile


65 posts in 1291 days

#13 posted 01-21-2012 05:01 PM


I’m working on getting this into the CarveWright PatternDepot as a project, and also offering a kit of hardware parts including built and tested electronics. Hope to have it ready soon.

I have another clock in the depot already:

-- Dick,

View CaptainSkully's profile


1233 posts in 2530 days

#14 posted 01-22-2012 08:14 PM

I’m very interested in getting one. Please post when they become available. Thanks.

-- You can't control the wind, but you can trim your sails

View Dennis Zongker's profile

Dennis Zongker

2513 posts in 2564 days

#15 posted 01-23-2012 05:19 PM

Great Looking Clock!!! Welcome to Lumberjocks.

-- Dennis Zongker

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