If your car still has a cassette deck (and you're not using it), Instructables user alanreid shows off how to build a smartphone holder right into that deck to make better use of that wasted space.

Q-I am the victim of an audio cassette. The tape wasn`t connected to the hub at the end of side A. Instead of auto-reversing, it simply ran out, the way tape used to in the old reel-to-reel days. I ...