I have a project in mind. I will use some photoresistors attached to a tv in order to detect changes in the light output. These changes can happen as fast as 10 times per second, something like: dimlight, brightlight, dimlight, brightlight, dimlight..... 10 times.

I was wondering if the photoresistor would be able to change it's resistance that fast or if it has a slow reacion time.

What Picbasic command would be best for this situation? the Pot command perhaps?

Is there a simpler way to monitor the screens activity with external components? ( I'm only interested in a tiny area of the tv)

would some kind of photodiode work?

thanks!