Hi everyone,
I'm working on a project that involves an analog video signal that needs to be switched on and off by a microcontroller. The signal will be coming from a camcorder, and going to a TV.
My question is: what the best way to switch the signal? I suspect that a relay would be the simplest, but I haven't got any 5v relays on hand (and don't feel like rewinding one, which I've done for previous projects). Where I live it takes at least a week for any ordered component to get here, so buying relays is not an attractive option.
After reading through a few wikipedia articles (http://en.wikipedia.org/wiki/Composite_video , http://en.wikipedia.org/wiki/Analog_television), it looks to me like a composite video signal is DC -- that is, the voltage on the signal wire never goes below the voltage on the shield. Is this the case? If so, could I switch the video signal using just an N-channel MOSFET? Would the MOSFET's on resistance interfere with the video signal, do you think?
Also, do you think it would work to run the video signal over a pair of wires in an ethernet-type cable, with RCA connectors at either end? Or would this hopelessly mess up the impedance situation?
If I don't hear otherwise, I'll probably try the MOSFET and see if it works.
Thanks for your help,
Adam
I'm working on a project that involves an analog video signal that needs to be switched on and off by a microcontroller. The signal will be coming from a camcorder, and going to a TV.
My question is: what the best way to switch the signal? I suspect that a relay would be the simplest, but I haven't got any 5v relays on hand (and don't feel like rewinding one, which I've done for previous projects). Where I live it takes at least a week for any ordered component to get here, so buying relays is not an attractive option.
After reading through a few wikipedia articles (http://en.wikipedia.org/wiki/Composite_video , http://en.wikipedia.org/wiki/Analog_television), it looks to me like a composite video signal is DC -- that is, the voltage on the signal wire never goes below the voltage on the shield. Is this the case? If so, could I switch the video signal using just an N-channel MOSFET? Would the MOSFET's on resistance interfere with the video signal, do you think?
Also, do you think it would work to run the video signal over a pair of wires in an ethernet-type cable, with RCA connectors at either end? Or would this hopelessly mess up the impedance situation?
If I don't hear otherwise, I'll probably try the MOSFET and see if it works.
Thanks for your help,
Adam