I have this idea for a black and white photograph to be scrolled across in front of a sensor which reads the shade of black/white at any point in time and send this data to arduino.
a) what kind of sensor do I need?
b) can this sensor read 'shades' or can it only tell if it's black or white?
Cheers!
If I understand correctly you want to build some sort of greyscale scanner?
Yes. A greyscale scanner is what I'm after. So I would need to build it? There's nothing already on the market?
There's nothing already on the market?
Yes, they're called "scanners" or "fax machines".
A QTI Sensor can tells shades of gray if you hook it up to an analog pin. Of you could overkill it and get a Linescan Imaging Sensor that pretty much takes a picture of your picture and saves it. Or, you could buy a light to frequency IC (TSL230R) and get your math on.
...or you could just scan it. You've got some options here.