Quote Originally Posted by Squibcakes View Post
Allegro make some really good current sensors which look like a TO-220 style case with built in shunt. Cant think of the part number at the mo but I've used in the past and work well up to 60amps.
Those are hall effect current sensors and cost around $10.00. The advantage is that it fully isolates the PIC from the current source and in the case of a motor that will be important due to back EMF. The other advantage is that there is very little power loss as opposed to using a series shunt resistor.