Rotary encoders would allow a full 360°with the added bonus of a digital output. Although exactly type depends on how much you are willing to spend. There rotary encoders specifically designed for use with motors but expect to pay between $30 to over $100 (at least for low volume orders) a piece. There are others intended for much lighter duty, like input knobs those can be less than a $1.00. Here's some of the selection avaialble at from one major supplier.