Update 'main.c'

main.c

@@ -6,34 +6,24 @@
 #define RELAY_SHUTOFF_DELAY 5000
 
 
+// Relay is active low, so HIGH disables the output.
 bool RELAY_STATE = HIGH;
-int INDEX = 0;
-int SAMPLES[SENSOR_SAMPLE_COUNT] = {0};
-
-
-int getMaxIntFromArray(int *arr, int len)
-{
-  int maxValue = 0;
-  for (int i = 0; i < len; i++)
-  {
-    if (arr[i] > maxValue)
-    {
-      maxValue = arr[i];
-    }
-  }
-  return maxValue;
-}
 
 
+// Get the maximum sensor value over 50 readings.
 int getSensorValue()
 {
+  int maxValue = 0;
   for (int i = 0; i < SENSOR_SAMPLE_COUNT; i++)
   {
-    INDEX = (INDEX + 1) % SENSOR_SAMPLE_COUNT;
+    int currentValue = abs(analogRead(SENSOR_PIN) - 512);
-    SAMPLES[INDEX] = abs(analogRead(SENSOR_PIN) - 512);
+    if (currentValue > maxValue)
+    {
+      maxValue = currentValue;
+    }
     delay(10);
   }
-  return getMaxIntFromArray(SAMPLES, SENSOR_SAMPLE_COUNT);
+  return maxValue;
 }
 
 
@@ -49,12 +39,14 @@ void loop()
   int sensorValue = getSensorValue();
   if (sensorValue < SENSOR_THRESHOLD)
   {
+    // If the relay is turned on sleep then remeasure sensor value.
     if (RELAY_STATE == LOW)
     {
       delay(RELAY_SHUTOFF_DELAY);
       sensorValue = getSensorValue();
     }
     
+    // If the sensor value has definitely dropped since the first measurement, then turn the relay off.
     if (sensorValue < SENSOR_THRESHOLD)
     {
       // Vacuum off.
@@ -66,5 +58,6 @@ void loop()
     // Vacuum on.
     RELAY_STATE = LOW;
   }
+  
   digitalWrite(RELAY_PIN, RELAY_STATE);
 }