distances are between 12 and 18" and not sure if the sensitivty in the analog domain would detect it well enough. Right now looking at hard on...hard off of the detectors with the PIC port. Neil Baylis wrote: Have you thought about putting the receivers on the same side as the transmitters, looking in the same direction? They would need to be looking at a surface that doesn't reflect much IR. When the object falls through, if any receiver sees an increase in light, you've detected it. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist --------------------------------- Need a vacation? Get great deals to amazing places on Yahoo! Travel. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist