Rotation sensor printing not working

so I’m trying to setup the rotation sensor to make a PID loop but some why when i try to print it it just says 0 even if it’s in a while loop and even if I’m spinning the motor it’s connected to.

the code (yes it’s in a while loop):

    Brain.Screen.clearScreen();
    Brain.Screen.print("test: %d", Rotation20.velocity(rpm));

so i’ve found out why the sensor wasn’t connected :skull: