View difference between Paste ID: U2NWQacd and sVWKjEYP

-#define MainPeriod 100
+#define NUM_SAMPLES 10
-long previousMillis = 0;
+
 volatile unsigned long duration = 0;
 volatile unsigned int pulseCount = 0;
 volatile unsigned long previousMicros = 0;
 
 
 void setup() {
   Serial.begin(19200);
   attachInterrupt(digitalPinToInterrupt(2), myIntHandler, RISING);
 }
 
 
 void loop() {
-  unsigned long currentMillis = millis();
+  unsigned long _duration;
   unsigned long _pulseCount;
-  if (currentMillis - previousMillis >= MainPeriod) {
+  float Freq_Hz;
-    // bufferize to avoid glitches
+  float Freq_RPM;
-    unsigned long _duration = duration;
+
-    unsigned long _pulseCount = pulseCount;
+  // bufferize to avoid glitches
   _duration = duration;
   _pulseCount = pulseCount;
 
   if (_pulseCount == NUM_SAMPLES) {
 
-    float Freq = 1e6 / float(_duration);
+
-    Freq *= 60;
+
-    Freq *= _pulseCount;
+
 
-    if (!(isnan(Freq))) {
+    Freq_Hz = _pulseCount * 1e6 / float(_duration); // frequency in Hz
-      Serial.print("freq: ");
+    Freq_RPM = Freq_Hz * 60; // frequency in RPM
-      Serial.println(Freq);
+
-    }
+    Serial.print("freq: ");
     Serial.println(Freq_RPM);
   }
 }
 
 
 void myIntHandler() {
   unsigned long currentMicros = micros();
 
   duration += currentMicros - previousMicros;
   previousMicros = currentMicros;
   pulseCount++;
 }