First we have a stack of coins in a tube. A spring pushes them forward. Then a plastic lever grabs them one by one. The servo moves the lever down. And releases it making it push the coin up. It is controlled by a timer (based on a 555) that fires with each hit to the block. The timer must be configured to make the cursor of the servo turn 360 degrees. Also parallel to the timer button is the play button. So you will hear the sound of the coin every time you press it.