diff --git a/main.cpp b/main.cpp
index 6163131..5fefa31 100644
--- a/main.cpp
+++ b/main.cpp
@@ -6,8 +6,7 @@
 #include "digital_out.h"
 
 class RotaryEncoderDriver {
-    int count{0};
-    bool last_lo{false};
+    volatile int count{0};
 
     Digital_out led{5};
 
@@ -19,32 +18,32 @@ public:
         led.init();
         eA.init();
         eB.init();
-        last_lo = eA.is_lo();
+
+        EICRA |= (1<<ISC01) | (1<<ISC00);
+        EIMSK |= (1<<INT0);
+    }
+
+    void update() {
+        count += eB.is_hi() ? 1 : -1;
+        led.set_hi();
     }
 
     int position() {
-        bool curr_hi = eA.is_hi();
-
-        if (last_lo && curr_hi) {
-            count += eB.is_hi() ? 1 : -1;
-            led.set_hi();
-        } else {
-            led.set_lo();
-        }
-
-        last_lo = !curr_hi;
+        led.set_lo();
         return count;
     } 
 
 };
 
+RotaryEncoderDriver encoder{2,5};
+
 int main() {
     uint8_t cycle{0};
 
-    RotaryEncoderDriver encoder;
     Serial.begin(9600);
 
     int prev_pos = encoder.position();
+    sei();
     while (true) {
         _delay_us(100);
         int curr_pos = encoder.position();
@@ -63,3 +62,7 @@ int main() {
     }
     return 0;
 }
+
+ISR(INT0_vect) {
+    encoder.update();
+}