# What would the math be to make the minute hand go really slow?

Have you ever seen the wall clocks with 7 days of the week? They are pretty sweet. I figure it would make a fun quarantine watch to make a dial that has 7 days of the week and one hand that takes 24 hours to move from one day to the next. What would the formula be to make the minute hand move at 24 hours in 7 sections? Does that make sense?

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It might even be cool to just have it be a third hand like a GMT hand. Regular hands for the time and then a third hand and a sub track that shows the days. You know what I mean? Google ‘Day Clock’ and you’ll see the kind of thing I’m talking about.

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Do you mean like military time?
This one has a 24hr hand in the center.

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I love the face @Rator!

Ok, so the expression for rotation…

The day of the week number ( 0 to 6 ) is given by #DOW#

Dividing the dial into 7 gives, 360 / 7 = 51.429 degrees
The hand needs to move this far in one day.

So at the beginning of each day ( midnight ) the hand needs to rotate to:

``````(#DOW#*51.429)
``````

Each day it needs to rotate a further 360/7 = 51.429 degrees

The hour rotation tag #DWFHS# returns an increasing angle from 0 to 360 in 24hrs

So at the beginning of each hour the hand needs to rotate an additional amount given by:

``````((#DWFHS#/360)*51.429)
``````

or
(#DWFHS#/7)

Combining the two expressions gives the total rotation expression:

``((#DOW#*51.429)+(#DWFHS#/7))``
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The above is if you want Sunday to be the first day of the week. If you want Monday to be the first day of the week then you need to subtract 51.429 degrees from the above expression or equivalently, subtract 1 from the day of the week tag:

Sunday 1st day of the week:

``````((#DOW#*51.429)+(#DWFHS#/7))
``````

Monday 1st day of the week:

``(((#DOW#-1)*51.429)+(#DWFHS#/7))``

((((360/7)/12)#Db#)+(#DOW#(360/7)))

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Hey @lucky.andrei - this would be a cool expression if you want the hour to jump once an hour; which would be a nice effect.

I’m not sure about using #Db# though…

The value of #Db# depends on the user’s preferred format:

From the documentation:

#Db# Hour in day using user’s preferred format (12 hour or 24 hour clock). NOTICE : This is the recommended tag for any digital times.

So the expression would only work if they have chosen 24 hour format.

….

Oh, and a hint about posting expressions in the forum…

A quirk of the forum is that the multiply symbol in expressions can be supressed if an expression is posted as normal text. One way to avoid this is to paste the expression on a clear line ( empty line above it ) using the preformatted text menu item at the top of the message edit window, the one with the “</>” icon. On a clear line, click on the icon and then type or paste in your expression over the top of the preformatted text.

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``````((((360/7)/12)*#Dk#)+(#DOW#*(360/7)))
``````

That’s probably better

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Ah, sorry …

#Dk# returns 1 to 24, so you will need to divide by 24 and not 12.

But also, I think you need a tag that returns 0 to 23 otherwise you get an error at midnight on Sunday morning.

Say the time is 24:01 Sunday morning.
#Dk# will return 24

The expression: ((((360/7)/24)#Dk#)+(#DOW#(360/7))) will equal 2.14*24+0 = 51.4 degrees

1 hour later at 1:01 it will equal 2.14*1+0 = 4.28 degrees

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``````((((360/7)/24)*#Dk#)+(#DOW#*(360/7)))
``````

excellent @mikeoday

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You could try it but I think it still will not work. I think you need to use #DH# instead of #Dk#.

@mikeoday I think let the author of the topic do it @anthony1

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Thanks Mike!

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OMG you guys are nuts! I shoulda paid attention in math class. #hindsight
Also, gotta love this community, everyone helping each other out, very cool.

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