Comments

Added comments
Added key reference link

emacs-keyboard/emacs-keyboard.ino

@@ -17,6 +17,7 @@ Key keys[NUM_OF_KEYS];
 
 void setup() {
   // Initialize key data
+  // https://www.arduino.cc/en/Reference/KeyboardModifiers
   // { buttonPin, keyCode, wasPushed }
   keys[0] = { 2, KEY_LEFT_CTRL , false };
   keys[1] = { 3, KEY_LEFT_ALT, false};
@@ -35,12 +36,14 @@ void setup() {
 
 void loop() {
   for(int i = 0; i < NUM_OF_KEYS; i++) {
-    if((digitalRead(keys[i].pin) == LOW) && (keys[i].wasPushed == false)) { // If the key is pressed...
-      Keyboard.press(keys[i].keyCode); // Send the key
+    // If key is now pushed, but wasn't before...
+    if((digitalRead(keys[i].pin) == LOW) && (keys[i].wasPushed == false)) {
+      Keyboard.press(keys[i].keyCode); // Send key down
       keys[i].wasPushed = true;
     }
+    // If key is now unpushed, but was before...
     else if ((digitalRead(keys[i].pin) == HIGH) && (keys[i].wasPushed == true)) {
-      Keyboard.release(keys[i].keyCode);
+      Keyboard.release(keys[i].keyCode); // Send key up
       keys[i].wasPushed = false;
     }
   }