On the GPS features of WiFiChron
The WiFiChron GPS-synchronized clock was begging for some documentation on the menu options and some details on its features. Here they are. The GPS-WiFiChron uses TinyGPS library to read the time from NMEA sentences (specifically GPRMC and GPGGA strings) from the uBlox Neo GPS module . The clock starts reading the data from the GPS module (using SoftwareSerial library, receiving on pin D7) 2 minutes after power up. Once a valid GPRMC or GPGGA sentence is received, the minutes and seconds (but not the hours) are automatically re-set from the satellite UTC time. The successful synchronization is indicated by the "up arrow" at the end of the scrolling date (e.g. Sunday August 21, 2016 ^). In order to automatically set the hours as well, I added a new menu option, GPS? (Yes/No) . When this is selected (set to "Yes"), the local hour is calculated based on the longitude, by estimating the timezone using a simple formula: // estimate time zone from longitude; int8_t g