Here's my latest project - yet another Arduino based clock! I had to buy the LED array (£6) but everything else was from my Arduino junk box. I used a Sweetpea Leofi as I have a few of these from a project of 5 years ago, but a nano would do the job very nicely.
My code for this is available on Github at GitHub - geo3geo/LED-clock: A very simple Arduino base clock
It's very straightforward and will lend itself to modification if you have other ideas.
There's a short video showing the setup operation using a single button at
There is a second version shown on Github as CircleClock_chimes_sound which has some extra features:
On the hour and half hour a LED pattern is displayed for 20 seconds
On the quarter hour a different pattern is displayed, for 10 seconds
On the hour a 'chime' sequence is played, but this is inhibited at night
(defined by low detected light level) and a series of tones sounded according
to the current hour. During the night these are very much shorter to make them less
intrusive. For silent operation, simply unplug the sound generator earpiece/loudspeaker
The sound output was an old earpiece of about 1K ohm. I didn't want it too loud.
It was plugged into a 3.5mm audio jack wired to +5 and to the soundPin (see code).
The pushbutton connects between setupPin and 0v with a pullup resistor (10K-ish)
between soundPin and +5.
There's a second video showing, what happens on the hour, at