Hello wise Arduino people!
First I must mention that I have an incredibly feeble understanding of electronics, so far it's just from a few days of research. I'm more confident with the software side of this problem so hopefully you can point me in the right direction in understanding the circuitry.
This is quite a unique idea (I'm presuming) but hopefully has a very simple answer.
The goal: Measure, reporting in real-time, the individual RGB colour channel values generated by a Philips AMBX side-light (they project colour in response to PC monitor activity/games/movies) . An Arduino would pass these values to the PC via serialprint. After that it should be easy, the PC-side can control separate RGB LED light strips on the walls via DMX RGB controller around the room. I already have experience with DMX software and compatible LED drivers.
Example of AMBX in action here: http://www.youtube.com/watch?v=rvjkhkHkBes (You can see sidelights... on either side. This would be copying that light effect across the whole wall either side of screen)
Now you may ask why hack it in such a brutal way if you could just intercept the calls from the PC software controlling the lights? Well, that would be ideal however as a closed protocol it seems impossible - I have found nothing on Google whatsoever anyway and it's far beyond my skill level to get into.
There are some very detailed schematics of the sidelight unit here: http://www.microlp.co.uk/amBX/circuit.html They are a bit overwhelming to me at the moment, I'm annoyed that I can't understand them!
So far, with a multimeter I have measured the forward voltage of each LED (separate red, green and blue SMD LEDs) and get perfectly usable values (around 2.5-3v max, under the 5v Arduino limit for analoginput).
However I am finding it hard to understand how to connect a circuit up to get that value into an Arduino Uno via the analog input, surely the Ardino's 5V and ground will be a problem connected to the AMBX 18V circuit? Do I just connect a wire from the LED cathode to the analog pin? Do I need resistors? Diodes?!
I'm waiting for delivery of my Arduino, luckily I haven't been able to kill it or the AMBX unit plugging in the wrong wires! As the AMBX units are discontinued and hard to find I don't want to get it wrong.
In the meantime I'd be really grateful to get some understanding of what I need to do to get the forward voltage figures into the Arduino safely, I imagine the schematics make this very clear, if only I could understand them! Then I guess the rest is straightforward (i.e. standard AnalogRead code x3 for each colour of LED).