Here’s an arduino library to calculate sunrise and sunset times based on date and latitude / longitude, i didn’t made the library, i took it from this website that doesn’t seem to work anymore: http://www.swfltek.com/arduino/sunrise
I’d like to give credit to the one who wrote it but i couldn’t find a creator name or contact anywhere!
i used it for my new “PS. I Love You” piece and incorporated a Noon function which returns the time when the sun is in mid sky.
Example included.
24.01.2010 update:
thanks Michael for your comment!
so full credits of the library goes to Michael Rice
and here’s the working link that i thought it was broken:
http://www.swfltek.com/arduino/sunrise.html
and the link to Michael’s ‘Timelord’ extended library with new great functions:

3 Comments
Thanks André, I’ll give it a go. By the way:
puts “HelloWorld to your blog!”
Time of noon was a clever mod!
The original is still there, you just dropped the ‘.html’ off the end of the url.
Since then I have rolled the SunRise library into a more expansive ‘TimeLord’ library, and with your permission I will include your noontime mod (with due credit of course).
Great!
i’ll update the info in the initial post!
thanks!