hi i work for a company that builds speaker cones. we have a camara system (keyence cv1200) to detect flaws such as holes in cone and thin spots, for advaced qc. but these systems are very exspisive. we only have them on 3 out of 18 of our machines. my quistion is does anyone know of a better and cheaper way of doing this? i know thay have to make a photocell that can see small amouts of light shing through a speaker. any help would be great.