You don't care about the lag in cron. You care about the variation of the lag.
Then again. The main cause of lag in a fog horn is the speed of sound You set cron to fire at T minus the average lag time. > On May 2, 2016, at 2:36 PM, Nick Sayer via time-nuts <[email protected]> > wrote: > > >> On May 2, 2016, at 9:51 AM, jimlux <[email protected]> wrote: >> >> >> The real question is whether "cron" is timely enough. No matter, just write >> a script (or python) that reads time in a loop (and you can put a sleep in >> there) and pulses the GPIO when needed. > > A Raspberry Pi with nothing else on its plate will have a cron-to-shell > script latency easily under 100 ms, possibly under 10. > > If it were me and I were triggering a relay for some sort of external > circuit, I’d probably be happy it was on the right side of 500 ms. If I cared > more than that, then step 1 would be to do as others have suggested and come > up with a microcontroller + GPS solution instead of NTP + cron. Ironically, > that’d be around the same price (albeit more engineering work). > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
