diff --git a/01 - JavaScript Drum Kit/index-START.html b/01 - JavaScript Drum Kit/index-START.html
index 4070d32767..3070cc7ef4 100644
--- a/01 - JavaScript Drum Kit/index-START.html	
+++ b/01 - JavaScript Drum Kit/index-START.html	
@@ -58,7 +58,25 @@
   <audio data-key="76" src="sounds/tink.wav"></audio>
 
 <script>
+function playSound (e) {
+    const audio = document.querySelector(`audio[data-key="${e.keyCode}"]`);
+    const key = document.querySelector(`.key[data-key="${e.keyCode}"]`);
+    if (!audio) return; // this will stop the function from running all together
+    audio.currentTime = 0; // rebobina al principio y me permite reproducir cada vez que pulso la tecla
+    audio.play();
 
+    key.classList.add('playing');
+  }
+
+  window.addEventListener('keydown', playSound);
+
+  function removeTransition(e) {
+    if (e.propertyName !== 'transform') return; // lo debe saltar si la propiedad no es transform
+    this.classList.remove('playing');
+  }
+
+  const keys = document.querySelectorAll('.key');
+  keys.forEach(key => key.addEventListener('transitionend', removeTransition));
 </script>