You know how in the movies and on TV, the perfect sound clip is playing for each moment?.. ....With this, you are the movie star, and the perfect song would always play, just for you.
Here's the skinny:
1) A bluetooth equiped hard drive mp3 player on which you load a substancial collection of
music you enjoy... For the device to work properly you would need a fairly large collection that has audio representation of all your various moods. i.e. Songs you'd listen to when you're sad, happy, excited, etc.
2) Either onboard the mp3 player (or seperated out) a small computer that will receive sensor data and make appropriate music selections. The programming should also be designed to recieve feedback data on its choices and write this information back to the hard drive player in a database. On subsequent plays, the choices would be affected by your previous analysis of the player's choices. Output could either be to headphones, or speakers.
3) A network of sensors which monitor clues to your given mood. For example.. A heartrate monitor. The player could use this data to determine your level of excitement or exertion. The player could then search it's database for a song with an appropriate BPM. A few sensors placed on the back and/or shoulders could record posture and give a lot of clues to your mood. The list could go on and on here.. The more sensors the user would decide to don, the more acturate the player could be using its data in conjunction.
Using this data, the player would pick songs based on an downloaded database of music styles, sounds, moods, BPMs, etc. (already existing.. try allmusic.com for example). Through connected, or bluetooth remote, you could then rate the players picks, and optionally take a mood snapshot... tell the player your mood so that it learns both what kind of songs you like to listen to in what moods, and how your body reacts to your various moods.
In it's secondary mode--learning off--the player could be used sans-sensors where it would function as any other mp3 player save for the fact that it would allow you to rate songs and monitor data such as how many times you've manually picked a song to play, or generally listened to a song. This would allow it to pick not only an appropriate song for your mood but the song specifically that YOU like.
The player would also include some basic setting sliders for music selection such as how much you're interested in hearing music you dont normally listen to, basic mappings of moods to song styles (so the player knos if you like happy or sad music when you're sad), etc. Optionally the player could also be set to alter your mood through music.. For example, if you're sad... the player could play the sad songs you like to hear, then gradually play increasingly upbeat and favored songs.
WIth an ever-increasing databse of moods and syles and the mappings between the two, the player would quickly become very adept at choosing for you, and you would have the perfect ambient music at all times.