DuncanWilliam77:
Can i use pinMode and digitalWrite functions to toggle on and off the 5v pin?
No. The 5V pin is not a digital output pin. It is part of the power supply.
IF the device draws less than 20mA you can power it from a digital output pin. For any higher current you will need to use a transistor.
Some chips have a reset input. Does the RFID board have a reset input?