I've been thinking on using a photo resistor, a photodiode or a phototransistor, but i don't know which will provide a better result, this is, the better response.
closed as not a real question by Kevin Vermeer Apr 17 '12 at 9:24
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a $15 BC scanner on Ebay would work better.
Photo Diode with transimpedance amplifier has highest gain, bandwidth Photo transistors are for slow apps. YOu might want a PD with Daylight blocking filter too to reduce interference. (cheap from Sharp or others) Very repeatable devices.