> I am somewhat new to pics and would appreciate some help with using a > photocell on a pic A-D port. The range of light on the photocell will > not cover the full resistance range of the photocell (whichever one I > use), Photocells convert light to electrical energy, and don't operate on varying resistance. Your best bet for measuring light intensity is to measure the photocell's short circuit current. This can be done with an opamp and feedback resistor. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu