An indwelling urinary catheter, such as a Foley balloon type, is transformed into an "intelligent catheter system" when a UroCycler(R) pressure-sensitive magnetic valve is attached to its output end to automatically control the pressure buildup of urine in the bladder, then open and release the urine to flow out and empty the bladder, thus restoring a normal, healthy cyclic function to benefit patient health and reduce the risk of infections and seven other catheter-associated problems