i have given the the vsyn signal to 555 timer. the output of 555 timer is being given to arduino board pin3 as an interrupt. the remaing circuit is attached. the problem i am facing is that leds would not turn off completely rather thay just dims.
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I can’t help with the vsync frequency – perhaps the people who sold you the camera will know. But as it is ‘v’ sync I would have expected it to be 60Hz.
I don’t see why you are using a 555 timer – why not feed the sync pulse directly to the Arduino? But assuming the LEDs are driven alternately at 60Hz then due to the persistence of vision, then I would expect them to appear to be on all the time but at half brilliance. But the LEDs are IR, so what are you using to view them?
Incidentally, you say 2 sets of LEDs, but your circuit shows only 3 LEDs.
You have 2 LEDs in parallel – a bad practice because one may take more current than the other.
The supply jack socket is wired unconventionally – the ‘ring’ (body) is normally wired to ground.