-#define EVENT_ONE_SEC_TIMER (1<<2)
-#define EVENT_MS_TIMER (1<<3)
-#define EVENT_USER_BUTTONS (1<<4)
-#define EVENT_ACCEL_UPDATE (1<<5)
-#define EVENT_AMBIENTLIGHT_UPDATE (1<<6)
-#define EVENT_POWER_CHANGE (1<<7)
-#define EVENT_COMMS (1<<8)
+#define EVENT_ONE_SEC_TIMER (1<<2) // one second timer for reguler clock
+#define EVENT_HALF_SEC_TIMER (1<<3) // half second timer for blinking displays
+#define EVENT_CS_TIMER (1<<4) // centisecond timer, e.g. for stop watch
+#define EVENT_USER_BUTTONS (1<<5) // button presses
+#define EVENT_ACCEL_UPDATE (1<<6) // accelerometer updates
+#define EVENT_AMBIENTLIGHT_UPDATE (1<<7) // ambient light sensor updates
+#define EVENT_POWER_CHANGE (1<<8) // power source status change
+#define EVENT_COMMS (1<<9) // communication, like Bluetooth I/O