Thankz 4 the tips everybody! Hmmm ... good ideas all round, both 555, 74HC14 or use the PIC. pity 'bout the ol'F84 being obsolete - my fav processor. i'll have a fiddle with programming a PWM o/p & see how i go. thankz again - Debbie :) http://personals.yahoo.com.au - Yahoo! Personals New people, new possibilities. FREE for a limited time. -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body