I've been using something called "Emotion Sense" on my phone. (I'm not sure if it's android only, or iOS as well.) I haven't learned much of anything from it yet, but I haven't been using it that seriously. It's a pretty simple interface, though. I might look into using TagTime.
oooh, that's much closer to what I was originally looking for. Thanks!
This is the public group instrumental rationality diary for September 16-30.
Thanks to cata for starting the Group Rationality Diary posts, and to commenters for participating!
Immediate past diary: September 1-15
Rationality Diaries archive