Elevation Display

This will display your current elevation. It even dims the display after sunset.

Error codes:

• 9001 - Display I2C not responding
• No GPS fix (after ~30s; shows ---- first, then -GPS)
• 9003 - GPS time/date not valid yet (tracked internally)
• 9004 - GPS location not valid yet (tracked internally)

Brightness behavior:

• Uses civil twilight (sun ~6° below horizon) so it stays bright a bit after sunset and before sunrise.
• nighttimeBrightness defaults to 0 (typically 0..15, where 0 is dimmest).

Boot / time behavior:

• While waiting for a GPS fix, the display shows ---- for ~30s, then -GPS if no fix.
• Once GPS time is valid, the display shows local time for ~10s, then switches to altitude.

Timezone configuration:

• Edit LOCAL_STD_OFFSET_HOURS and LOCAL_OBSERVES_US_DST in GPS-Alt.ino to match your timezone.
• Common US standard offsets: Pacific -8, Mountain -7 (Arizona is -7 with DST off), Central -6, Eastern -5, Alaska -9, Hawaii -10.

For elevations above 9,999 feet, the first character will be displayed in hex. So 11,200 ft will be B200.

I haven't tested above 16,000 ft.

Parts required:

• Arduino Metro Mini
• GPS
• 7 Segment Display with I2C backpack
• 12v to microUSB power supply - Dongar Tech makes many adapters that give you a plug-and-play USB port from your exisitng mirror wiring harness.

Some soldering & coding may be required!

• Connect GPS to +5v, GND, Digital pins 7 & 8
• Connect display to +5V, GND, SCL, & SCA (A4 & A5 on the Metro Mini)
• Upload the sketch included in this repository to the Arduino using the Arduino IDE & a USB cable!