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[on:]

I am looking to wire up some relays for the purpose of home automation. I am following this ( http://www.glacialwanderer.com/hobbyrobotics/?p=9) tutorial. I have wired up everything correctly as I can switch the relay on and off with the arduino. When I wire the live (black) wire into the relay, nothing happens. I am not sure what I am doing wrong. I have read the arduino reference materials for relays, but have not really gotten anywhere. The relay that I am using can be found here http://www.allelectronics.com/make-a-store/item/RLY-513/MINI-SPST-3-VDC-RELAY/1.html.  The relay is definitely capable of switching AC voltage.

Any help is greatly appreciated.

Photo of the project can be found here: http://micah.ath.cx/projects/arduino/relay/01.jpg

[Reply #1 on:]

When I wire the live (black) wire into the relay, nothing happens.

What do you mean by 'nothing happens'?  Does the Arduino no longer control the relay?  That would be very strange because the AC contacts should be quite isolated from the coil contacts.  And it they weren't the Arduino would emit a flash, bang, and puff of smoke.

[Reply #2 on:]

The arduino continues to switch the relay throughout the entire process. (everything IS isolated). However, the load (light that is plugged in) is not switched on and or off. the light continues to stay off even though the relay is "switching" it on and off.

[Reply #3 on:]

Sounds like there is a problem with the wiring or the relay contacts.  If you disconnect one of the wires from the relay contacts and touch it to the other wire, does the light light?  If not the problem is somewhere else (bulb, fixture, wires, switch).  If it does light up the problem is the relay contacts not making contact.

[Reply #4 on:]

Are you referring to removing a live wire from the relay and touching it to the other live wire? Or are you referring to the 5V and signal pins coming from the arduino. I tested the cable that goes to the light without the relay, and the light lights up. So, there must be some wiring issue with the relay itself.

[Reply #5 on:]

> Are you referring to removing a live wire from the relay and touching it to the other live wire?

Yes. 

> Or are you referring to the 5V and signal pins coming from the arduino.

No.

> I tested the cable that goes to the light without the relay, and the light lights up. So, there must be some wiring issue with the relay itself.

If you are sure enough about the cable, fixture, and bulb that you want to proceed as if they were proven good then you must conclude that your relay is faulty and replace it.