if you truly want to burn diatonic harmony into your mind and you love technology here is what you can do.Most phones have mp3 playback.All you have to do is record different mp3's with one chord each i.e Cmaj7,Dm7,Em7,Fmaj7,G7,Am7,Bm7b5.Now put these fellows in a playlist and click shuffle.Put on your earphones and call out the chord if you recognize it.Soon you will be superb at this. Change the inversions and do the same. You will master this too.If you have a better randomizing tool even better,the shuffle is predictable :P.
Then pick another key and work with it the same way. Then scramble keys and work. Work on your ear it's really great fun and in this age of technology we can use everyday appliances to create some really helpful tools.
Learning how this harmony works is a real blessing.Sing a random song as the shuffle plays and you will see how random chords will kick your mind around.Do enjoy :)