Here is a simple Arduino project witch can be made with this DIY LED display and some other cheap parts.
Step 1: Parts and Tools
Step 2: Building the Circuit and Coding
Build the circuit as in the photograph above(if you are using the the DIY LED display this may be a bit tricky).
Step 3: Using It!
The left button counts up(to nine) and the right button counts down.
Zero = no tone
One = low tone
Two = higher tone