Merge pull request #5 from FoamyGuy/master

adding compass example

Author: makermelissa

docs/examples.rst

@@ -6,3 +6,12 @@ Ensure your device works with this simple test.
 .. literalinclude:: ../examples/lis3mdl_simpletest.py
     :caption: examples/lis3mdl_simpletest.py
     :linenos:
+
+Compass Example
+---------------
+
+Use the magnetometer to calculate compass headings.
+
+.. literalinclude:: ../examples/lis3mdl_compass.py
+    :caption: examples/lis3mdl_compass.py
+    :linenos:

examples/lis3mdl_compass.py

@@ -0,0 +1,26 @@
+""" Display compass heading data five times per second """
+import time
+from math import atan2, degrees
+import board
+import busio
+import adafruit_lis3mdl
+
+i2c = busio.I2C(board.SCL, board.SDA)
+sensor = adafruit_lis3mdl.LIS3MDL(i2c)
+
+
+def vector_2_degrees(x, y):
+    angle = degrees(atan2(y, x))
+    if angle < 0:
+        angle += 360
+    return angle
+
+
+def get_heading(_sensor):
+    magnet_x, magnet_y, _ = _sensor.magnetic
+    return vector_2_degrees(magnet_x, magnet_y)
+
+
+while True:
+    print("heading: {:.2f} degrees".format(get_heading(sensor)))
+    time.sleep(0.2)