added state machine

tutorials/coding-challenge/step-4-code.md

@@ -5,6 +5,7 @@ parent: "Coding Challenge"
 nav_exclude: true
 ---
 
+## Without Statemachine
 ````python
 import time
 import board
@@ -67,4 +68,96 @@ while True:
         leds.fill(color_off)
         leds.show()
 
+````
+
+## With statemachine
+````python
+import time
+import board
+import analogio
+import digitalio
+import neopixel
+
+# States
+state_on_loud = 0
+state_on_quiete = 1
+state_off = 2
+state_memory = 3
+current_state = 0
+
+
+# Register sensors
+button = digitalio.DigitalInOut(board.D4)
+button.direction = digitalio.Direction.INPUT
+
+sound_sensor = analogio.AnalogIn(board.A0)
+
+# Register LED
+leds = neopixel.NeoPixel(board.D13, 1, auto_write=False, pixel_order=neopixel.GRBW)
+
+# colors
+color_off = (0,0,0,0)
+color_on = (0,0,0,10)
+
+leds.fill(color_off)
+leds.show()
+
+
+timer_mark = 0
+timer_duration = 1
+
+color = None
+triggered = False
+
+color_memory = []
+
+while True:
+
+    if current_state == state_off:
+        # make sure the LED is off
+        leds.fill(color_off)
+        leds.show()
+        # check if we should turn on
+        if sound_sensor.value > 30000:
+            # Start the timer!
+            color = (random.randint(0,70),random.randint(0,70),random.randint(0,70),0)
+            color_memory.append(color)
+            timer_mark = time.monotinic()
+            current_state = state_on_loud
+        elif button.value is True:
+            current_state = state_memory
+
+    elif current_state == state_on_loud:
+        leds.fill(color)
+        leds.show()
+        if time.monotinic() - timer_mark >= timer_duration:
+            current_state = state_off
+        elif button.value is True:
+            current_state = state_memory
+        elif sound_sensor.value < 25000:
+            current_state = state_on_quiete
+
+
+    elif current_state == state_on_quiete:
+        leds.fill(color)
+        leds.show()
+        if time.monotinic() - timer_mark >= timer_duration:
+            current_state = state_off
+        elif button.value is True:
+            current_state = state_memory
+        elif sound_sensor.value > 30000:
+            # Her start the timer!
+            color = (random.randint(0,70),random.randint(0,70),random.randint(0,70),0)
+            color_memory.append(color)
+            timer_mark = time.monotinic()
+            current_state = state_on_loud
+    elif current_state == state_memory:
+        for color in color_memory:
+            leds.fill(color)
+            leds.show()
+            time.sleep(1)
+        leds.fill(color_off)
+        leds.show()
+        color_memory = []
+        current_state = state_off
 ````