Making a circular clock

Thread Starter

FroceMaster

Joined Jan 28, 2012
556
Hi
Have this plan of making a clock with time, minut and second hand
If i use 3-4 LED in series and use a transistor to drive it i will still have 180 outputs
If i use 3-8 line driver and a ex 74hc375 or similar to drive it i would end up with 64 output. And then 3 sets of that. All driven by a microchip ex 16f1509
Is that possible to do or do i have to total rethink everything

Any hints

Logic circuits and microchip is fine by me
 

Bernard

Joined Aug 7, 2008
5,360
12 drivers for hours?
60 drivers for minuets ?
60 LED's around rim for seconds ?
Take hours, needs 12 control pins so to reduce count use 74HC154 16 step stepper requiring only 4 address pins. 74HC family uses 5 to 6V VDD, so use a buffer ( 74FCT244ATP, 8 stages or ULN family ) to drive LED's in parallel with a resistor for ea. LED ? 4- 74HC154's for min. & sec. 4 address lines & 4 control lines for ?
 

Thread Starter

FroceMaster

Joined Jan 28, 2012
556
More like this,
Where the time on this is "15:10:00" "Watch.png"

The 'Problem" is that i would have 180 outputs to control.

Any hint on doing that ?
i have planes to do it like this "first lay.png"
i know i miss a lot on the controls, but i think you get the big Picture on how..
 

Attachments

hp1729

Joined Nov 23, 2015
2,304
More like this,
Where the time on this is "15:10:00" "Watch.png"

The 'Problem" is that i would have 180 outputs to control.

Any hint on doing that ?
i have planes to do it like this "first lay.png"
i know i miss a lot on the controls, but i think you get the big Picture on how..
24 hour clock? 15:10 is 3:10 PM.

I gave some thought to such clocks but simplified it down to just 12 positions. 12:00, 12:05, 12:10 etc. A lot fewer LEDs.
 

blocco a spirale

Joined Jun 18, 2008
1,546
It's not really a big problem just very time consuming to build, you can do it all with shift registers, a bit of logic and a 1 second timebase, the PIC is not necessary. Divide the clock into 3 concentric rings with hours in the middle (12 outputs), then minutes (60 outputs), then seconds (60 outputs). If you use open-collector outputs (which you probably will) and "steering" diodes, you can overlap the "hands".
 
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