Vasile Surducan wrote: >On 3/30/06, Bob Axtell wrote: > > >>I'd do it with a PIC10F20X. It would be 1/10 size, cost 1/5 as much, and >>would be more reliable than a 555. Take about 5 minutes to write this code. >> >> > >Bob, >Anyway or anyhow you're looking , 555 is cheapest than any microcontroller. >Usually 10x555 = 1cheap microcontroller, as price. >Output curent capability of a 555 is greatest than any IO. >Not talking you have to write the code, or if you want ONE monostable >this is waste of time. >However there is one problem with 555 monostable: the first false >trigger at power up. > > > I don't agree. The 555 itself costs about 0.25 USD, but the capacitors and resistors and extra transistor to create a reliable retriggerable circuit easily pushes it over $1.50 USD. I can buy the PIC10F200 for $0.50 USD in 100 qty. He didn't say he wanted ONE. He said he wanted to correct a problem on a already-laid-out production PCB. PLUS, It has no power-up glitches. and will run with an accuracy of 3% WORST-CASE, 1% typical. The code is about 20 code words. I will write it myself if he wants. --Bob -- Note: To protect our network, attachments must be sent to attach@engineer.cotse.net . 1-520-850-1673 USA/Canada http://beam.to/azengineer -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist