Hi, I need to detect the presence of 3 colors at a maximum distance of 7-10cm. (fixed distance, position, orientation etc). The colors are very specific and cannot be altered - the light conditions are also fixed - bright indoor lighting (think casino). The colors fly by very fast, and they are BRIGHT RED, DULL GREEN and BLACK. Thats right - reading results from a roulette wheel. I baught a "BALLUFF BKT" LASER sensor. (www.quack.cc/36970.pdf) This detects the RED/Black perfectly but i cant make it distinguish the green from the black . (it has a teach function, but it doesnt see enough of a difference in contrast i guess). I liked this sensor because it used a visible laser diode (aiming is important) and it has fast reaction time and a long sensing range. the documentation says upto 15cm - but in reality i had it upto 25. So i am looking for a "green color" sensor - more specific than just a 'contrast' sensor. It needs a range of about 7-10 cm, and if possible, a visible aiming mark. I read somewhere that a red led/laser will not pickup greens well because green absorbs most red light - and i have seen "green led" contrast scanners around - but only for short-range . does anyone knows of a green-led/laser contrast scanner with a better than 2cm maximum range ? Thanks Alex.