Approach

Initially, we started with just a single device, which would retrieve two pieces of information: 

1) Currently playing song from Spotify

2) Currently playing song's genre

Based on the genre of the currently playing song, the frame would display a specific color (we had created a genre-color mapping in the code).

We realized that there were shortcomings to just using one device, so we decided to create another device that would communicate with the first device. This second device would show what genre of music the first device's owner was listening to. In this way, it could 'communicate' the mood of one person to the other. Obviously, there are limitations to using genre as a way to communicate mood, as different genres can have very different feelings associated with them. We decided to use genre, though, because it can generally communicate overarching mood (think classical music = relaxed, pop = high energy, rock = high energy, cool jazz = relaxed, etc.)

An alternative would have been to use other pieces of meta data associated with a song that is captured by Spotify, such as danceability (which would indicate how fast-paced and rhythmic a song is).

Next, we wanted to leverage the goodnight lamp to communicate songs that make you think of the other person. To do this, we added a button to the frame that, when pushed, would pull the currently playing track and add it to a shared playlist so that the other person with the other frame could receive notification that a song had been added to their shared playlist.