Using 4x water flow sensors (yf s401) with arduino mega

[Nick_Pyner]

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Arduino Mega interrupts

The Arduino reference for attachInterrupt command gives this chart for interrupts and pins on the Mega board: BOARD INT.0 INT.1 INT.2 INT.3 INT.4 INT.5 Mega2560 2 3 21 20 19 18 However may pinout diagrams show: INT.0 on Pin 21 INT.1 on pin 20 INT.2 on pin 19 INT.3 on Pin 18 INT.4 on Pin 2 INT.5 on Pin 3 Which is correct?