I just ordered my Arduino Mega 2560 (I haven't recieved it yet) I am looking to create a circuit to sense when a composite, s-video, or component is active.
I am using this chip to switch video lines http://www.fairchildsemi.com/ds/FM/FMS6501.pdf
I have read up a bit on video signals and it seems (and I may be wrong) that they output about 1 volt max normally, but I am unsure of how to check the line without degrading the signal.
the chip I am using (FMS6501) has a gain which you can set to 6dB, 7dB, 8dB and 9dB. It also has bias and clamp, but to be honest I am not 100% of what those are for.
so currently I am simply splitting the input on both the FMS6501 and the arduino, but I am afraid of degradation should I use some sort of IC or component to split the signal? or since there is a variable gain, can I simply split it and check if it is high, if so, I will use I2C to set the correct register to switch the video... does the split to test the line need a diode or resistor?
My goal is to keep the video at best quality possible, and check if video is coming through. Anyone with video input experience could chime in, that would be awesome. Thanks.
edit: also, here is my simple diagram idea:
I know it says picaxe, but that is just a place holder for some programmable ic, I am attempting it with arduino first.