[time-nuts] Clock Project Help

Hal Murray hmurray at megapathdsl.net
Wed Oct 28 18:37:55 UTC 2009

> Where the problem lies is that I need to find the IC chips for clocks
> and build a display.

I'm not sure what you are looking for.  Are you looking for "IC chips" to 
keep time or to display the time?

You don't need a special chip to keep time.  Just count CPU cycles.  Most 
embedded type CPU chips have a way to do that.

If you run ntpd, it will correct for the error in your crystal.  (makes a 
good thermometer)

What type of display do you want?  Aside from Nixies, I can think of two 
possibilities.  One is LEDs.  The other is LCD.

There are lots of small LCD modules available.  Typical sizes are 1x20 and 
2x20 characters.  They usually come with backlights.   Most of them are 
really bitmapped.  They just have a built-in font to simplify programming if 
all you want is text.  One of those would make a fine clock display.  You 
could show the time in a huge font, and put the date and whatever in the 
leftover space.

You can get them packaged as a USB module so you could prototype everything 
from your PC.

You may be able to get a special LCD designed for a clock, but they will 
probably be hard to find unless you want to buy a zillion of them.

7 segment LED displays are readily available.  You may be able to get one 
specialized for clocks: 4 digits with a : in the middle.  Or you could build 
your own from single/double packages with discrete LEDs for the :.  Go to 
Digikey and poke around.

One for your checklist...  You probably want some sort of photo-transistor to 
sense the ambient light level so you can dim the lighting at night.  (unless 
you want to use the clock as a night light)

These are my opinions, not necessarily my employer's.  I hate spam.

More information about the time-nuts mailing list