I need to measure pistons from 11.00 mm to 14.00 mm each piston increment on a five units like 11.00-11.05 I'm thinking about shining a led read the return light with ADC and have my pic calculate the size of the piston but there's a draw back with this method keeping the ambient light out. any idea on how to measure this piston thanks -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu