Reading Sensing and Controlling current flow is a requirements in a wide variety of application including, over-current protection circuits, switching mode, battery chargers, power supplies, digital watt meter and programmable current source, etc.. The ACS721 current reading module is based on ACS712 Sensor which can detect AC, DC current signal accurately. The maximum AC / DC can be detected using ACS712 will reach 30 amp and present current signal can read via analog IO port of Arduino, Product available for this module are 30A, 20A, 5A. for this demonstration we will used the ACS712 30A.