Programming DS3231 Alarms and Interupts

I spent a long time trying to get a set up the alarms on a DS3231 and couldn't find much help, I'm new so maybe I was looking in the wrong places. Finally I have achieved what I wanted and in doing so wrote 3 smallish sketches to help me. I thought I would contribute these to help others. The sketches are:- 1) Set_Alarm.ino. This will allow both alarms to be set for Day/Date/Hour/Min/Sec etc 2) Read_Alarm.ino. This reads the Alarm registers and prints out in English,when the Alarm will be fired, and finally 3) Test_Int.ino. A simple test of using an external interupt.

I haven't tested all the possible options, i.e. using the time in 12 Hour clock mode as I always use 24 hour time.

I modified an existing library but cannot find where I got it from so I have uploaded my modified libraries to GitHub along with the 3 test programs I wrote. They can be downloaded from

Thanks to those who have replied to my post. Please email if you find any errors.

Thank you, I have a DS3231 too, while I don't need alarms or interrupts yet, it might be helpful in the future ;)

Since you didn't include the library that you used in those sketches, here is a link to it (I suppose it's this one, right?):,57642.0.html

I wrote a library, one of these days I'll get back to completing the doc: