Compass_Rose
This is code to control an RGB LED with an HMC5883L chip.
I used the chip and carrier board sold by Marlin P Jones Inc (part # 31585 MP). The Adafruit Sensor Library ( https://github.com/adafruit/Adafruit_Sensor ) to handle the interface details.
My particular device put the LED on pins 9, 10, and 11, and the compass on A4 (18) and A5 (19). The HMC5883 has a hard-coded I2C address (0x1e), so you're going to have to do some fancy hardware stepping if you want more than one controlled by a single Arduino or if you have another device which also has that address.
The color values for the RGB are in "color.h". Each color in the RGB light has 255 brightness levels. The compass gives about 2 degree accuracy, so theoretically you could have up to 180 different colors indicating directions. I found that more than the basic 6 in the RGB color scheme ( Red, Green, Blue, Yellow, Magenta, and Cyan ) were too many for my eyes to distinguish. Your mileage may vary. Set up a spreadsheet with the various RGB combinations, save it to a CSV, and then use some basic text manipulation to fill the Colors array in color.h if you wish to experiment further with this.
If you are using an RGB LED with a common cathode, 0 is brightest and 255 is off. I suspect that common-anode RGB LEDs work the opposite way (0 is off), but I don't have any of them around to test.
Copyright (c) Charles Shapiro October 2017 This file is part of the Compass Rose project
Compass Rose is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Foobar is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Compass Rose. If not, see <http://www.gnu.org/licenses/>.