LED's

if you want to isolate it and allow for as many LEDs as you want use a transistor and some resistors the whole setup (if you bought the stuff at radioshack) would run about $2 or less...

A relay is a horrible idea, it would draw way too much current (even without changing state) plus if it did work the thing would not last too long until the contact broke off lol

man that picture is larger than i expected it to be..  ohh well at least it is easy to read

ohh man I dont know what i was thinking that is completly wrong, I ment to use an NPN transistor, sorry its been a long day.. here is the correct diagram:

Correct me if I'm wrong, but some LED's have built in diodes and

can't have the polarity reversed. Just switch the wires on the LED that doesn't

work. I believe most LEDs are around 3 volts, I seriously doubt 4 volts is going to

damage the alarm brain...

All leds function as diodes as well, although they can not handle the same amounts of current and reverse bias voltages because they are not made to.

LEDs do not really operate on voltage, they operate on current. the only reason they have such a high voltage drop is because they are based on gallium arsenide, not silicon. A resistor is used to limit current because the PN junction will not.

Not sure what you mean about 4 volts damaging the brain?