Sunrise and Sunset

Projects General Guidance
1

Hi i am building a automatet ligth for outside. I have tried different librarys as TimeLord, but i found these to be not so accurate. UP to 1 hour wrong. I have set the latitude and longitude and timezone to +1 also tried just 1. This is in norway. Anybody have any tips to get this working? Another library / code. I am using an RTC to get time for the UNO.

Regards

2

You must be doing something wrong. I've tried several sunrise/set programs, and they are all within one minute or two of being correct. How about "daylight savings time"?

Here is an Arduino sun position calculator that is accurate to a few arc minutes.

3

Thanks. i will look into this link. As an example. for today i get these values:

Sunrise: 07:14
Sunset: 20:10

But according to: timeanddate.com it should be:
Sunrise: 07:02
Sunset: 19:53

With These settings:

Date 27/03/2016
LONGITUDE = -9.59;
LATITUDE = 59.25;
TIMEZONE = 1;

if someone can test and see if they get the same values or if am doing something wrong.

4

if someone can test and see if they get the same values

Post the code, using code tags.

It is very unlikely that your longitude is -9.59 degrees (West of the Prime Meridian), which is somewhere in the ocean. Oslo would be about 10.5 degrees.

5

#include "TimeLord.h"

const int PROGMEM TIMEZONE = 1;
const double PROGMEM LONGITUDE = -9.59;
const double PROGMEM LATITUDE = 59.25;

TimeLord myLord;

void setup()
{
Serial.begin(9600);
myLord.TimeZone(TIMEZONE * 60);
myLord.Position(LATITUDE, LONGITUDE);
}

void loop()
{

byte day[] = {0, 0, 0, 27, 3, 2016};

myLord.SunRise(day);
Serial.print("Sunrise: ");
Serial.print((int) day[tl_hour]);
Serial.print(":");
Serial.println((int) day[tl_minute]);

myLord.SunSet(day);
Serial.print("Sunset: ");
Serial.print((int) day[tl_hour]);
Serial.print(":");
Serial.println((int) day[tl_minute]);

delay(5000);
}

6

const double PROGMEM LONGITUDE = -9.59;Try 9.59

7

WOW. now its accurate to within a couple of minutes :slight_smile: ( if i add 1 Hour sinse we entered DST last nigth )

I just have to ask. Why does this happend? Becuase according to Google the GPS coordinates here was with a minus (-) in front of LONGITUDE

8

There is no universal convention for the sign of longitude, but Google Maps in the U.S. uses positive for east longitude, and so does that program.