Cleaned up, documented

Author: evaherrada

Circuit_Playground_Brake_Light/code.py

@@ -1,51 +1,53 @@
-# pylint:disable=invalid-name,import-error,missing-module-docstring
-
-# Great pdf on moving average filters:
-# https://www.analog.com/media/en/technical-documentation/dsp-book/dsp_book_Ch15.pdf
 import time
 import math
 from adafruit_circuitplayground import cp
 
 brightness = 0
-l = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
-l1 = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-      0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-      0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-      0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-      0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+l10 = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+l50 = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+       0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+       0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+       0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+       0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
 
 i = 0
+cp.pixels.fill((255, 0, 0))
+
 sleep = False
-decel = 0
+
 while True:
     x, y, z = cp.acceleration
 
-    # moving average n=10, not super smooth, but not terrible either
-    l.append(z)
-    l.pop(0)
-    avg = sum(l)/10
+    # moving average n=10, not super smooth, but it substantially lowers the amount of noise
+    l10.append(z)
+    l10.pop(0)
+    avg10 = sum(l10)/10
 
     # moving average n=50, very smooth
-    l1.append(z)
-    l1.pop(0)
-    avg1 = sum(l1)/50
+    l50.append(z)
+    l50.pop(0)
+    avg50 = sum(l50)/50
 
-    if avg - avg1 > 1:
+    # If the difference between the moving average of the last 10 points and the moving average of
+    # the last 50 points is greater than 1 m/s^2, this is true
+    if avg10 - avg50 > 1:
         if i > 3:
+            # Detects shake. Due to the very low shake threshold, this alone would have very low
+            # specificity. This was mitigated by having it only run when the acceleration
+            # difference is greater than 1 m/s^2 at least 3 times in a row.
             if not cp.shake(shake_threshold=10):
-                cp.pixels.fill((0, 0, 255))
-                cp.pixels.brightness = 0.25
+                cp.pixels.brightness = 1
                 start = time.monotonic()
                 sleep = True
         i += 1
 
-    # sleep variable is for short circuiting
+    # sleep variable is for short circuiting. Not really necessary, but it makes things run faster
     elif not sleep or time.monotonic() - start > 0.4:
-        cp.pixels.fill((255, 0, 0))
-        cp.pixels.brightness = abs(math.sin(brightness)) * 0.25
+        # Sine wave used for the color breathing effect.
+        # Max brightness can be adjusted with the coefficient.
+        cp.pixels.brightness = abs(math.sin(brightness)) * 0.5
         brightness += 0.05
         i = 0
         sleep = False
-        decel = 0 
 
     time.sleep(0.02)