Along the lines suggested below, one of the CD40x0 series devices (probably CD4060) has an iscillator and divider in the same IC. You can get extremely long delays from the single IC. The excessively enthused could use a crystal for accuracy. A PIC etc has the advantage of design flexibility. -----Original Message----- From: Hardy e/ou Rafael Pinto To: PICLIST@MITVMA.MIT.EDU Date: Tuesday, 31 March 1998 22:45 Subject: Re: Need help with a 30 min. timer -----Original Message----- Date: Segunda-feira, 30 de Mar¨o de 1998 16:11 > Hello everybody, >I'm new to the world of PIC's.I was wondering if anybody have any suggestions to > help me out. Here's my problem: I need a timer that once activated will run 30 > minutes, after the 30 minutes is up a relay will be triggered. Any code, > schematics, or advice would be greatly appreciated. I have the ability to use > and program these PIC's: 12C509, 12C672, 16F84, 16C63, 14000. Any and all > comments welcomed. Thanks in advance!!!!!!!!!!!!!!!!!!!!!!!!!!! > > Steven Kosmerchock > >EMAIL: steve.kosmerchock@CELWAVE.com > Do you REALLY need a microcontroller for this????? Why not using a 555 astable and a BIG divider... The error would be much less then 5 % when correctly adjusted! Or even better use the 555 as a monostable with large timing! It doesn't even have to be programmed!