Smackflad:
thank you for replying.
I'm pretty sure you haven't understood what I'm trying to do.
Iam not an electrician but I know some things.
What I am trying to do need the cables that are in the wall switch. I CAN NOT finish the project with out them.
If I call an electrician first of all he is not going to do what I need him to do. Also I'm gonna miss the magic of creating something by my own. I like electronics and I'm currently studying it.
IMHO, you are missing the point.
mains wiring, mains power, is NOT electronics.
if you want to study to be an electrician, great.
if you want to study electronics, then early on, you need to understand the difference.
in your study of electronics, you use sensors. detect gas, detect moinsture, temperature, movement.... those are your tools.
your question as far as electronics goes, is
'how to best detect a thing'
we, as a group will often try to make you look and make sure that you are trying to sense the correct 'thing'
in your case, it is either that there is a light that is working, or there is power.
they are both separate and also dependant on each other.
you can sense electricity by measuring voltage, or current, and even by the flux field generated by electricity in the wire. there are many devices that are able to sense the present of electricity without touching the wires.
THAT is the electronics, that is what we do.
you can use a CT, or current transformer to detect the current flowing in a wire. with the circuit at the switch completed, but the lamp broken, there is no current flow. if the lamp is present and working, there would be current. a CT circuit does not touch the wires.
you can connect a phone charger so that regardless if the lamp is present, if there is power, you know there is power (but not that there is light)
simply put, we deal with electronics and touching mains voltage to electronics will destroy the electronics.
you MUST, you are REQUIRED, it HAS TO BE, that there is some device, sensing the mains power, that is NOT mains power, but outputs a signal so something results in a low voltage signal that the electronics can sense.
if you want to sense that there is mains power, you need some device. the plug in phone charger is the simplest to detect voltage .
if you want to detect light, the LDR is the simplest
your study of electronics will improve when you think of the sensor and what it really sees, and how limited it is to the one thing it senses.