Jinx wrote: > Think it might be. I tested some PIR circuits a few years ago and > found that cold outside air blowing through the open door into a > warm room was quite apparent on the 'scope and would have > triggered the following logic/micro. Are you sure you were really measuring the air and not hard objects that it cooled down? ******************************************************************** Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products (978) 742-9014. Gold level PIC consultants since 2000. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist