Thanks, I have it working now. I used a 1k Ohm resistor between the logic drive input and the base of the NPN transistor as suggested and it works. I'm just wondering how you're supposed to choose what resistor to use on the base?(How did you know to use a 1k Ohm instead of the 4.7k Ohm.
On...
I have not tried a relay driver IC but the transistor method looks promising. I just have a couple questions.
I got the relay at radio shack.
http://www.radioshack.com/product/index.jsp?productId=2062478&cp=&sr=1&origkw=relay&kw=relay&parentPage=search
# Maximum switching current of 0.5 A
#...
I have a data acquisition device that outputs 3 volts if the sensor is activated. My relay only activates when a 5 volt source is put across the coil. What is the easiest way to step up the 3 volt control signal.