diff --git a/led_bikewheel.ino b/led_bikewheel.ino
index a81cca6..68c962c 100644
--- a/led_bikewheel.ino
+++ b/led_bikewheel.ino
@@ -1,16 +1,31 @@
 const int HALL_PIN = 2;
+const int ROUND_COUNT = 2;
 
 void setup() {
+  Serial.begin(115200);
   pinMode(LED_BUILTIN, OUTPUT);
   pinMode(HALL_PIN, INPUT);
 }
 
 void loop() {
-  int hall_value = digitalRead(HALL_PIN);
-  if (hall_value == HIGH) {
-    digitalWrite(LED_BUILTIN, LOW);
-  } else {
-    digitalWrite(LED_BUILTIN, HIGH);
+  float start = micros();
+  int count = 0;
+  bool change = false;
+  while (count < ROUND_COUNT) {
+    if (digitalRead(HALL_PIN) == LOW) {
+      if(!change) {
+        change = true;
+        count++;
+      }
+    } else {
+      change = false;
+    }
   }
-  delay(10); //debounce? 
+
+  float end = micros();
+  float passed = (end - start);
+  Serial.print("Diff: ");
+  Serial.print(passed);
+  Serial.println("micro seconds");
+ 
 }