I'm trying to build a DIY RFID security system based on a post I saw on the old Arduino forum: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1267227582/24#24
HID ProxPoint RFID Card Reader
Electronic Door Strike (opens on 5v, 2a of current)
5v Power Supply (powers door strike)
I modify lines 8 and 9 of the sketch to match Serial Number and Site Code of my HID Key Fob and upload it to the Arduino. When I scan the fob the strike opens for three seconds and closes as it should. My problem is when I try to repeat the process with the same fob the strike will not open unless I scan it at least three times. When I unplug the power supply for the door strike and just have the relay with nothing live attached to it I am able to scan the fob multiple times and the relay will switch on and off normally. This leads me to believe I need a diode or a resistor somewhere but I'm not sure what i need exactly or where I should put it. Can someone help me out here? I have attached a drawing to get a better idea what I have now.