adding a gravitational constant and made the conversions a bit clearer

Author: Sigafoos

adafruit_lis3dh.py

@@ -61,6 +61,9 @@
 DATARATE_POWERDOWN       = const(0)
 DATARATE_LOWPOWER_1K6HZ  = const(0b1000)
 DATARATE_LOWPOWER_5KHZ   = const(0b1001)
+
+# Other constants
+STANDARD_GRAVITY = 9.806
 # pylint: enable=bad-whitespace
 
 
@@ -138,7 +141,12 @@ def acceleration(self):
 
         x, y, z = struct.unpack('<hhh', self._read_register(REG_OUT_X_L | 0x80, 6))
 
-        return x / divider * 9.806, y / divider * 9.806, z / divider * 9.806
+        # convert from Gs to m / s ^ 2 and adjust for the range
+        x = (x / divider) * STANDARD_GRAVITY
+        y = (y / divider) * STANDARD_GRAVITY
+        z = (z / divider) * STANDARD_GRAVITY
+
+        return x, y, z
 
     def shake(self, shake_threshold=30, avg_count=10, total_delay=0.1):
         """Detect when the accelerometer is shaken. Optional parameters:

examples/accel.py

@@ -37,8 +37,8 @@
 # Loop forever printing accelerometer values
 while True:
     # Read accelerometer values (in m / s ^ 2).  Returns a 3-tuple of x, y,
-    # z axis values.
-    x, y, z = lis3dh.acceleration
-    print('x = {}G, y = {}G, z = {}G'.format(x / 9.806, y / 9.806, z / 9.806))
+    # z axis values.  Divide them by 9.806 to convert to Gs.
+    x, y, z = [value / adafruit_lis3dh.STANDARD_GRAVITY for value in lis3dh.acceleration]
+    print('x = {}G, y = {}G, z = {}G'.format(x, y, z))
     # Small delay to keep things responsive but give time for interrupt processing.
     time.sleep(0.1)