test PR do not merge {descriptive title of change}

src/rpm_sensor.ino

@@ -0,0 +1,66 @@
+const int SensorPin = 2;
+
+volatile unsigned long LastPulseTime = 0; // Time when last pulse is detected
+volatile bool objectPresent = false; // Track if the object is currently detected
+volatile bool readyForNextPulse = true; // The new pulse is only registered when the object leaves
+volatile bool newValidPulse = false; // A new pulse has been recorded
+unsigned long TimeBetweenPulses = 0;
+float RPM = 0;
+
+void setup() {
+  Serial.begin(9600);
+  pinMode(SensorPin, INPUT_PULLUP);  
+  attachInterrupt(digitalPinToInterrupt(SensorPin), PulseDetected, CHANGE);  // Trigger interrupt on both rising and falling edges of the sensor signal
+}
+
+void loop() {
+  RPMcalculator();
+}
+
+void PulseDetected() {
+  unsigned long CurrentTime = micros();
+  bool sensorState = digitalRead(SensorPin);
+
+  // Debounce: ignore pulses faster than 1ms apart
+  if (CurrentTime - LastPulseTime < 1000) return;
+
+  if (sensorState == HIGH && readyForNextPulse) {
+    // Object just arrived
+    objectPresent = true; // Mark that object is detected
+    readyForNextPulse = false; // Prevent duplicate detection
+    LastPulseTime = CurrentTime;  // Save pulse timestamp
+    newValidPulse = true;
+  }
+
+  if (sensorState == LOW && objectPresent) {
+    // Object has left, ready for next pass
+    objectPresent = false; // Object is no longer detected
+    readyForNextPulse = true; // Ready to detect the next incoming pulse
+  }
+}
+
+void RPMcalculator() {
+  unsigned long currentTime = micros();
+
+  // Timeout: reset RPM if no object has passed in the last 5 seconds
+  if (currentTime - LastPulseTime > 5000000) {
+    RPM = 0;
+  }
+
+  // If a new valid pulse has been registered, compute RPM
+  if (newValidPulse) {
+    static unsigned long PreviousPulseTime = 0;
+
+    if (PreviousPulseTime > 0) {
+      TimeBetweenPulses = LastPulseTime - PreviousPulseTime;  // Time between current and last pulse
+      RPM = 60000000.0 / (float)(TimeBetweenPulses);  // Convert microseconds to RPM
+    }
+
+    PreviousPulseTime = LastPulseTime; // Update last pulse time
+    newValidPulse = false;
+  }
+
+  Serial.print("RPM: ");
+  Serial.println(RPM);
+  delay(1000);  // Display update every second
+}