Yesterday I was ask to extend my Arduino AudioTools library to support RTTTL. To be honest, I had no clue what this is, so I had to look it up: RTTTL stands for Ring Tone Text Transfer Language and was developed by Nokia to transfer ringtones to cellphones.
It basically descibes the notes and durations in simple text form. My library supports different sound generators and also provides the frequencies of all notes: so all I needed was to provide a parser for RTTTL and link it up with the existing functionality.
The new class is called RTTTOutput and you just provide the generator and output device in the constructor and then you can play the audio by printing the RTTTS string