I have some problems driving a 5V relay from the Arduino.
If I connect the relay to GND and 5V on Arduino, it works just fine. But, if I connect the relay to GND and Pin 2 on Arduino, and set pin 2 high, nothing happens. The current between GND and Pin 2 is 5V when the relay is not connected. As soon as I connect the relay, this drops to almost 0V, even though the pin is set to HIGH.
This is the relay I'm using: http://www.engphys.ubc.ca/phys253/datasheets/OMRONG5LE.pdf. I'm pretty sure I used the exact same setup in an earlier project and that it worked just fine then.
Any suggestions to what might be wrong? I'm a little concerned that the Arduino is not able to cope with the current the relay draw, is that correct?