How many seconds is Millis()

Using Arduino Programming Questions
1

Hi.

I am building a timer where a relay is on for 1 hour. I am using the millis() function. I wanna know how long a hour is in millis().

Can i just do it this way:

60min * 60 * 1000 = 3600000UL?

or is a millisecond really 1024 due to the Arduino "counts" via timer0?

The timer doesn't have to super precise.. +-5min is okay.

2

The milliseconds in 1 hour is 60 * 60 * 1000 = 3,600,000

3

It's definitely not 1024 millis in a second. ( Sometimes it does not take 1000 µs fom one millis() value to the next, to compensate for timer0 )

And, on my arduino UNO with 16MHz crystal, it's usually (at 23 °C) rather 998 to 999 millis() in a second.

But 3600000UL is precise enough for your "requirement" (+- 5 min/h)

4

Thanks a lot guys.

I was my mistake. :* I had misread another post completely. I was also i bit confused myself :~