Epicycle Clock

June 22, 2023 9:37 AM

Sophie Houlden announces they've made an epicycle clock web app.

You can support them on Patreon.

posted by AlSweigart (20 comments total)

I think it would be possible to create a physical one. You don't want to have a turning mechanism at the end of the hour hand, but rather just have the minute and hour hand connected by a free-spinning pin and the actual mechanism is underneath the clock, tracing out the path of the epicycle.
posted by AlSweigart at 9:40 AM on June 22, 2023 [1 favorite]

...I was hoping the link would explain - what exactly is an epicycle clock?
posted by EmpressCallipygos at 9:40 AM on June 22, 2023 [2 favorites]

I guess it helps to know what an epicycle is. If you ever played with a Spirograph, you've got an idea. It's the path traced by a point on a circle as it revolves around another circle.

In the case of this clock, the central circle is traced by the hour hand, and the epicycle is traced by the minute hand, and there's a button you can click to turn on a second hand, which adds another layer.
posted by adamrice at 10:01 AM on June 22, 2023 [2 favorites]

So cool! Now do a giant one with a year hand and a month hand.
posted by aws17576 at 10:11 AM on June 22, 2023 [1 favorite]

Wait
posted by aws17576 at 10:12 AM on June 22, 2023 [3 favorites]

So cool! Now do a giant one with a year hand and a month hand.

And a Millennium hand and an eon hand!
posted by tommasz at 10:20 AM on June 22, 2023 [24 favorites]

I was hoping Sophie had kept the minute hand pointing at its usual angle, which would've had the pleasing counterintuitive-at-first-sight result of an eleven-lobed epicycle, for the eleven times in each twelve hours the minute hand and hour hand align. But she's plumped for the "intuitive" twelve-lobed epicycle, meaning the minute hand has been sped up to turn around thirteen times in twelve hours.
posted by finka at 10:21 AM on June 22, 2023 [4 favorites]

Unfortunately, it also means that when you're 30 minutes past the hour, the minute hand is pointing away from the clock's rim, and so it clashes with the intuitive way we've all been taught to interpret analog clockfaces.

It also bothers me more than it should that the epicycles' intersection points aren't at :15 and :45.
posted by The Pluto Gangsta at 10:29 AM on June 22, 2023 [1 favorite]

I made a little clock with two LEDs that don't move; we all rely on it. Each LED has one of six colours: red yellow green cyan blue magenta. The top LED indicates the hour in six hour cycles. The bottom LED indicates the minute in ten-minute increments. Which is really all you need for most human timekeeping purposes. The colours do repeat four times daily but if you're not sure whether a green hour is 2am, 8am, 2pm, or 8pm then you have problems a clock cannot solve.
posted by seanmpuckett at 10:41 AM on June 22, 2023 [4 favorites]

i kinda want to see a second hand, moar epicycles
posted by mhum at 10:54 AM on June 22, 2023 [3 favorites]

Oh wait, I resized my window and now I can see the button in the lower-right to activate the second hand. My thirst for more epicycles is slaked
posted by mhum at 10:55 AM on June 22, 2023 [8 favorites]

if you're not sure whether a green hour is 2am, 8am, 2pm, or 8pm then you have problems a clock cannot solve

On waking up I may not remember my own name. I think giving an indication of whether it is mid-morning or mid-afternoon is one of the most important problems a clock can solve.
posted by justsomebodythatyouusedtoknow at 2:31 PM on June 22, 2023 [2 favorites]

I'm glad they still gave us a digital display of the time at the top.
posted by hydrophonic at 3:38 PM on June 22, 2023

So I happened to click on this basically slam bang on the stroke of midnight and was briefly a bit confused and thought it wasn't working or something, but yeah this is cool.
posted by motty at 4:03 PM on June 22, 2023 [1 favorite]

Clever, and visually pleasing.

That said, there is a reason the traditional and intuitive clock/watch dial has persisted largely unchanged for centuries.
posted by Pouteria at 8:35 PM on June 22, 2023 [2 favorites]

I learned about Euler's rotation theorem when trying to build a similar clock Unity as an experiment for a clock idea. The idea was a circle around the hour with an Indicator of the current hour.

Attached to this wheel/circle was a smaller wheel (minutes), that turned and as it did so rotated the parent (hours) hand.

Likewise.

Anyways, if you've never done the coding or don't know much math for rotation - it's important which thing is rotated first, Rotating the arm, then the attached hand gives very different results than rotating the hand and then the arm. Anyways, just thought I'd leave that little mathy thing as a tidbit. Peace y'all miss being able to enjoy the 'fi
posted by symbioid at 10:55 PM on June 22, 2023

I had the same thought as finka, so I patched it (click "absolute"). Not sure if it's more or less confusing.
posted by you at 1:09 AM on June 23, 2023 [1 favorite]

you

Thanks for that.

How do I download it? Just save the whole web page?
posted by Pouteria at 5:08 AM on June 23, 2023

I realized that the minute hand is pointing in the "right" direction relative to the hour hand. Putting a dial with minute hashmarks at the end of the hour hand wouldn't be as visually pleasing as the epicycles, but it would make the clock more readable.
posted by adamrice at 6:20 AM on June 23, 2023

So cool! Now do a giant one with a year hand and a month hand.

And a Millennium hand and an eon hand!

The last one is a shrimp!
posted by polytope subirb enby-of-piano-dice at 1:15 PM on June 23, 2023 [3 favorites]