I made a clock. Yup, another clock

[michaelwillems]

So why did I build another clock? It’s been done before.

Yes but. The but is:

• minimalist design
• Uses an Arduino nano ESP32
• Internet connected to Arduino IoT
• it has a battery backed up real time clock … AND ntp!
• and you can disable ntp if desired
• it auto-dims at night
• It has an Uber cool font (credit given)
• It is very well documented (link below)
• It is all operated using just one button

The manual has everything including code, discussion, pics, parts list, etc:

Clock

Always open to discussion. A lot of things have to be decided. How to handle ntp. How often to update it (once per minute for 5 minutes, then hourly). How to operate all this with just one button. And so on. I had fun.

[odometer]

For making the colon flash on and off, I would recommend using the seconds of the time (odd or even) as your "heartbeat". This provides reassurance that your clock is actually keeping time.

[johnerrington]

Your construction and wiring are exemplary. Well done.

[michaelwillems]

This is indeed what happens.

[odometer]

How do you accomplish that? I don't see any second % 2 or second & 1 in your code.

[michaelwillems]

See the “once per second” part of the loop. Every second I invert the colon. If it’s on, turn it off; if it’s off, turn it on.

[odometer]

What I meant was, as a "heartbeat" for your RTC, to verify that it is running.

[michaelwillems]

Isn't that the same thing? If it is running, the green LED inside flashes, AND the colon flashes.

[michaelwillems]

But if you mean, specifically the RTC, I would see if I can read the time from it.

[odometer]

What I meant was, to make sure that the time was advancing and not stopped (like a stopped analog clock: you can still read the time, but it does not advance). But maybe the scenario of an RTC with a stopped time but that you can still read from is so unlikely that there is no real need to check for it. I have heard of stopped RTCs, though, but I don't remember the details.