fix(vl53l1x): Address review comments on proximity alert example.

Author: Kaan Ozen

lib/vl53l1x/examples/proximity_alert.py

@@ -1,3 +1,9 @@
+"""Proximity alert using VL53L1X distance sensor and buzzer.
+
+Beeps the buzzer when an object is detected within 200 mm. The pitch
+increases as the object gets closer.
+"""
+
 from time import sleep_ms
 
 from machine import I2C, Pin
@@ -6,11 +12,11 @@
 
 DISTANCE_THRESHOLD_MM = 200
 
-# sensor configuration
+# Sensor configuration
 i2c = I2C(1)
 tof = VL53L1X(i2c)
 
-#buzzer initialisation
+# Buzzer initialisation
 buzzer_tim = Timer(1, freq=1000)
 buzzer_ch = buzzer_tim.channel(4, Timer.PWM, pin=Pin("SPEAKER"))
 buzzer_ch.pulse_width_percent(0)
@@ -21,19 +27,19 @@
         print("Distance: {} mm".format(distance))
 
         if distance < DISTANCE_THRESHOLD_MM:
-            #frequency ranging from 1500 (really close) to 500 (at 200mm)
-            freq = (1500- (distance * 5))
-            #security limits
+            # Frequency ranging from 1500 (really close) to 500 (at 200mm)
+            freq = 1500 - (distance * 5)
+            # Security limits
             freq = max(500, min(1500, freq))
 
             buzzer_tim.freq(freq)
             buzzer_ch.pulse_width_percent(50)
         else:
             buzzer_ch.pulse_width_percent(0)
 
-
         sleep_ms(50)
 
-
 except KeyboardInterrupt:
-    buzzer_ch.pulse_width_percent(0) #Properly cut the sound when the user presses CTLR+C
+    pass
+finally:
+    buzzer_ch.pulse_width_percent(0)