I finally finished my piggy bank project that I made for my daughter (she's 3).
4 Coin Acceptor
Adafruit Wave Shield
16x2 RGB LCD
Various buttons, etc.
The way it works is that you deposit coins and after a pre-defined time out it will "tally" the deposit. A receipt can be printed after the deposit is made by pressing the button. A switch activates the electrochromic film to "see into" the piggy bank where the money is. Of course there are various buttons to play kid-friendly songs (and I added a key-switch to disable the music if it gets over used :))
Thanks for help from the forum members!