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Coup Perdu Movement

Hi Steve, Just played your YouTube video on your coup perdu movement.

Looks great. Not too sure if my wife will agree to another clock in our living room.

Anyway, considering the fact that this is going to be a desktop clock and that the weight required is small, this would mean that the winding of the weight will be interesting to give a long runtime. Are you looking at using a small geared motor to provide the energy to wind the weight up every few minutes.

Great work

Krys S

12 comments

12 Comments

Massimiliano Molinari

Nov 02, 2022

Hi Steve, I looked at the moped on eBay it cost me a lot of $ 10 plus $ 19 shipping, I noticed that there are different types on Amazon, I don't know, could you tell me the correct scooter on Amazon?. thank you.

Steve

Nov 02, 2022

Replying to

They look like the correct motors

Massimiliano Molinari

Nov 02, 2022

Replying to

Steve, the two gearmotors links that I sent you, you wrote me that they can be fine, the measurements of the two motors change slightly, are they equally fine to insert it in your container?, I also noticed that between the two models one has the shaft 10 mm long the other 20 mm, which of the two can I buy?. a thousand thanks !!!!

Steve

Nov 02, 2022

Replying to

10mm is good. 20mm will work but it will stick through the pinion. It could be cut off if needed.

ksmietanski

Oct 20, 2022

Easy Build Pendulum Clock & Coup Perdu Clock

Hi Steve.

It is early spring here in Australia and I have been working in the garden this morning.

After seeing your new Coup Perdu winding mechanism, which is very similar to Clayton Boyer's system on the SpringTime clock, whilst gardening I have been thinking about trying to copy the drive system and retrofitting it into your 32 day pendulum clock. Currently I have a 2.5kg weight on the clock and it has been going really well for about 9-12 months.

Do you think that this is at all feasible with a different gearing ratio??

Also, congratulations on the new cock design, I looks awesome. Really can't wait to build it.

I also really like your electro magnetic pendulum clock although you don't seem to endear it as much.

Krys S

Steve

Oct 20, 2022

Replying to

Hi Krys,

The Coup Perdu clock lifts a 1-2 ounce weight every few minutes. The drive weight sits between the minute hand and the second hand rotating once every 24 minutes. This allows a relatively small weight to be used.

Many of the other rewind mechanisms are designed to lift a large weight much less often. Lifting the weight on the 32 day clock would have to do this. The overall power might be the same, but it would require stronger motors and higher current batteries. The switches would also need to handle the larger currents.

The Coup Perdu uses a small motor with small batteries and a low current reed switch as a trigger.

I am looking into elegant ways to add electric rewind into some of my older clock designs. The beauty of the Coup Perdu clock is that the heavy drive weight can be eliminated. This gets rid of all the gears between the minute hand and the winding drum. The bottom third of the clock can be eliminated. In the 32 day clock, this would eliminate 3 of the gears on the left side of the clock.

I am adding a wall mount option into the Coup Perdu clock. The base will have options that will look better when mounted against the wall. This might be similar to the rewind mechanism in Clayton Boyer's Swingtime clock.

Steve

Oct 03, 2022

Thanks Krys,

I tested about a dozen different DC gear motors and this one was the clear winner in terms of size, noise levels, power levels, and price.

www.ebay.com

8 PC N20 Gear Motor, 1000:1 Ratio Gear Reduction, 3V to 6V, w/ JST cable | eBay

GEAR RATIO. AT MAXIMUM EFFICIENCY. Larger quantities are available. (100, 250, 500, 1000, etc). Motor model # JL-12FN20-1006 as shown below. LENGTH OF GEAR BOX(L). This is a finished assembly with connector and ready for use.

The prototype is coming along nicely. The biggest hurdle has been developing a reliable trigger mechanism. A mercury tilt switch would be extremely reliable, but they are getting hard to find because of the mercury. This looks like a reasonable replacement

https://www.amazon.com/Gebildet-Normally-Magnetic-Induction-Multi-Use/dp/B081JHQ55P

They are rated at 0.5A and the motors only require 30-40mA. The prototype uses a 1-2 ounce weight that lifts every few minutes to power the clock. Initial experiments show the clock could have a 5 month run time with 2 AA batteries.

Steve

ksmietanski

Oct 03, 2022

Replying to

Hi Steve, This makes great sense. Also, with a self winding system, it should be easy to make a desktop table clock a wall hanging clock.

Really looking forward to this one.:-)

Krys S

Steve

Oct 04, 2022

Replying to

Yes, it should be modifiable for wall mounting. I am trying to hide the batteries in the base on the desktop version. A few other changes might be needed.