Added auto brake light code.py

Author: evaherrada

Circuit_Playground_Brake_Light/code.py

@@ -0,0 +1,51 @@
+# 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]
+
+i = 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=50, very smooth
+    l1.append(z)
+    l1.pop(0)
+    avg1 = sum(l1)/50
+
+    if avg - avg1 > 1:
+        if i > 3:
+            if not cp.shake(shake_threshold=10):
+                cp.pixels.fill((0, 0, 255))
+                cp.pixels.brightness = 0.25
+                start = time.monotonic()
+                sleep = True
+        i +=1
+
+    # sleep variable is for short circuiting
+    elif not sleep or time.monotonic() - start > 0.4:
+        cp.pixels.fill((255, 0, 0))
+        cp.pixels.brightness = abs(math.sin(brightness)) * 0.25
+        brightness += 0.05
+        i = 0
+        sleep = False
+        decel = 0 
+
+    time.sleep(0.02)