On 2011-10-17 17.34, mailing list wrote: > I have a machine running OBSD 4.4 which as an APC Back-UPS ES 550. > Anyway to have OpenBSD detect when power is coming from Battery? > (Plan on sending the system sending me an sms if so)
Apart from the suggestions elsewhere in the thread, in the good old days I used to detect power outages by simply using a 12V power adapter and soldering together a special cable connecting the +12V to the DCD pin of an RS 232 serial connector. Then I plug the adapter into a wall socket and connect the cable to a serial port on the computer, then simply open() the serial device and issue a blocking read(). If/when the read() later on returns EOF, I know that the carrier has been dropped, thus I have no power from the wall. (And since the program is obviously still running, what power I have must come from the UPS.) Then give it a grace period of a few minutes (as long as you dare with whatever UPS and load combination you have), then check again. If DCD is still out, shut down the machine in a controlled fashion. Otherwise lather, rinse, repeat. Can't be any simpler, really. :-) Best regards, /Benny > I found the following: http://www.apcupsd.com/ > My understanding is you need a usb connection to the ups. (one I have has no > USB) > > Anyone know of a package using detection over voltage changes (or > something)? > > Thanks
