On Wed, Dec 29, 2010 at 12:01 PM, Bob Blick wrote: > > On Wed, 29 Dec 2010 08:18:50 -0500, "Olin Lathrop" said: > >> What I came up with is only for one-off use, but it worked nicely. =A0Us= e >> two >> LEDs and two light-dependent resistors. =A0I had the analog circuit driv= e >> the >> two LEDs in opposition smoothly. =A0When the voltage was at either extre= me, >> one LED would be on brightly. =A0In the middle they were both on somewha= t. >> This has the added advantage of the control and controlled circuits bein= g >> optically isolated. > > I seriously considered this, but it's been a long time since I bought > any cds cells except from places like Radio Shack, and I was concerned > about channel matching. > > Thanks, > > Bob > Aren't CdS cells a RoHS headache? I would try to avoid them for new design= s. Regards, Mark rmarkrages@gmail --=20 Mark Rages, Engineer Midwest Telecine LLC markrages@midwesttelecine.com --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .