How can LED trigger NC sensor?

I have a RAID card for my server which doesn't communicate to OS when there is a drive failure.

I would like to detect when the 'health' led is active and have it trigger an NC contact on my Caddx security system.

I thought of 2 ways to do this, one hacky and one not.

Non-hacky way: Design circuit off of led pins which wires straight into alarm zone/common terminals.

Hacky way: Run a photodiode into small project box with the LED at other end of box. When LED lights...sensor is triggered. I guess this is what they call an opto-isolated input?

I'm a software guy and no zip about electronics. Help would be appreciated greatly.

You can just use an optocoupler from your existing led and have that trigger the relay.
The optocoupler is virtualy what you just said but all in one package.

right on

thanks...that sounds like exactly what I want.