Sverre Holm blogged about his Arduino clock project:
Its main features are:
- Controlled by a GPS module outputting data over an RS232 serial interface, and handled with the TinyGPS++ library
- Shows raw GPS data such as UTC time and date, position, altitude, and number of satellitess
- Shows derived GPS data such as 6-digit locator
- Finds local time and handles daylight saving automatically using the Timezone library
- Finds local sunset and sunrise, either actual value, or civil, nautical, or astronomical. The library is Sunrise.
- The clock also gives local solar height based on the Sunpos library from the K3NG rotator controller.
- Finally, the clock also provides the lunar phase based on ideas found here and using a reference new moon on 11 November 2015, 11:47 (UNIX time 1447264020)
More info at LA3ZA Radio & Electronics.